Cover comprising solidified seal material

Abstract

The present disclosure regards a cover (20) for use during sealing a through hole (10, 10a) of an evacuated gap (6) of a vacuum insulated glass unit (1)The cover comprises a covering body (21), a major cover surface (21a) at a solder side of the cover (20), and a seal material comprising a solidified glass solder material (22). The glass transition temperature of the solidified glass solder material is lower than the glass transition temperature of the covering body (21). The cover (20) may comprise one or more predefined evacuation channels (23) having a channel width (Wc), which channel width (Wc) extends between opposing walls (24a, 24b) of the solidified solder material (22). In some embodiments, the solidified glass solder material (22) may cover at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface. Also, the disclosure relates to a Method of manufacturing a vacuum insulated glass unit, a vacuum insulated glass unit (100) and a method of manufacturing one or more covers (20) comprising solidified solder material.

Description

[0001] Cover comprising solidified seal material

[0002] The present disclosure relates to a method of manufacturing a cover for sealing an evacuated gap, and to a method of manufacturing a vacuum insulated glass unit. Moreover the present disclosure relates to a cover, to a workpiece and to use of a cover.

[0003] Background

[0004] Vacuum Insulated Glass (VIG) units provides advantages such as improved heat insulation when compared to material use, advantages related to reduced weight, space saving and other advantages.

[0005] The improved methods for manufacturing VIG units and components for VIG units are under development. The method of manufacturing a VIG unit among others comprises evacuating a gap between two glass sheets through a through hole in a glass sheet, and the evacuated gap is then sealed by a sealing solution. The evacuation of the gap is provided by means of a pump, e.g. by means of an evacuation cup or by means of placing the entire VIG unit assembly in a vacuum chamber. Various sealing solutions for sealing the through hole and hence the evacuated gap have been suggested.

[0006] Some sealing solutions suggest using a glass tube or ceramic tube that is then heated to melt and thereby seal the evacuated gap. This heating and melting of the tube may e.g. be provided by means of a heating element arranged in an evacuation cup.

[0007] Patent document EP3865464 A1 discloses a solution where a cover is used for covering a through hole in glass sheet of a VIG unit so as to seal an evacuated gap. An adhesive fixes the cover to the glass sheet, and the cover may be placed in a stepped through hole. One or more gas flow tunnels is / are formed by providing discontinuations in the adhesive to enable evacuation of the gap. Patent document KR20230086925A illustrates a solution for sealing an evacuation hole of a VIG unit. Here, a surface of a cap made from tempered glass is covered by sintered glass frit, a spring is in contact with the sintered glass frit and is fixed in a compressed state in the VIG. Patent document CN219824008U discloses sealing a VIG unit gap by means of a cover arranged in a stepped / countersunk through hole. A laser is used for sealing the gap by melting the a glass body and / or the cover. Patent document WO20217779 discloses use of a pressing mechanism arranged in an evacuation cup so as to exert a force onto a cover / lid used for sealing an evacuated gap of a VIG unit. Patent document KR20130022535 discloses a further sealing cap solution used for sealing an evacuated gap of a VIG unit. Here, the sealing cap is maintained below the plane of the VIG unit glass sheet surface so as to not protrude to the outer surface of the glass sheet surface. Patent document LIS2021388667 discloses providing a an exhaust channel passage through which gas is exhausted.

[0008] The present disclosure may provide a solution which enables providing an improved seal of an evacuated gap of a VIG unit. The present disclosure may additionally or alternatively provide a solution which enables a simple and a reliable manufacturing of a VIG unit. The present disclosure may additionally or alternatively provide a cost efficient solution, may enable fast and efficient VIG unit manufacturing, and / or may help to provide an improved VIG unit.

[0009] Summary

[0010] The present disclosure relates, in a first aspect, to a cover for use during sealing a through hole of an evacuated gap of a vacuum insulated glass unit. The cover comprises a covering body and a major cover surface at a solder side of the cover. The cover moreover comprises a seal material comprising a solidified glass solder material. The glass transition temperature of the solidified glass solder material may be lower than the glass transition temperature of the covering body. The cover comprises one or more predefined evacuation channels having a channel width. The channel width extends between opposing walls of the solidified solder material. Each of the one or more predefined evacuation channels extends in an evacuation direction towards the outer periphery of the cover.

[0011] The predefined evacuation channel(s) may help to facilitate an advantageous, such as fast and / or efficient evacuation of a gap of a VIG unit. This may e.g. become relevant when evacuating larger gaps of a VIG unit assembly for subsequent use at e.g. a building window, a refrigerator door / lid or the like. The solidified solder material may comprise a low amount of binder material and / or the like, and has been pre-heat treated so that outgassing of the solder material, when it is softened to seal the evacuated gap of the VIG unit by sealing a through hole, is reduced or substantially prevented. Optionally, in one or more embodiments of the present disclosure, the solidified glass solder material may cover at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface.

[0012] The inventors have found by test that providing a cover where a large portion of the major cover surface, such as e.g. at least 40 %, at a solder side of the cover is covered by the solidified solder material may provide a cover with improved characteristics, such as e.g. providing a consistent and strong sealing of the evacuated gap. This may e.g. be relevant when providing one or more predefined evacuation channels at the cover between walls of solidified solder material. Suh evacuation channels may help to provide enhanced, such as more efficient and / or faster, evacuation of the gap, but need to be closed after use in order to seal the evacuated gap of the final VIG unit. It has been found that a combination of providing a solidified solder material that covers a larger part of the cover surface may provide an advantageous cover when the cover comprises predefined channels extending between opposing walls of the solidified solder material.

[0013] It may also provide a cover of a type that may perform consistently, so that a plurality of covers, such as at least 100 covers or at least 500 covers each performs consistently during gap evacuation and subsequent sealing of the evacuated gap.

[0014] It may also enable providing a well performing, space saving cover where the final height of the cover after use and including the seal material thickness at the final VIG unit may be reduced.

[0015] In one or more embodiments of the present disclosure, each of the one or more evacuation channels has a channel width and a channel length, wherein the channel length is larger than the channel width. This may e.g. provide a cover where the closing of the evacuation channel after use may be more easy and / or consistent while still enabling improved gap evacuation through the evacuation channel.

[0016] In one or more embodiments of the present disclosure, the channel length (Lc) is at least 1.3 times larger, such as at least 2 times larger, such as at least 2.8 times larger than the minimum channel width. This may e.g. provide a cover where the closing of the evacuation channel after use may be more easy and / or consistent.

[0017] In one or more embodiments of the present disclosure, the width of the evacuation channel is below 1.8 times, such as below 1.5 times, such as below 1.3 times the minimum channel width along said channel length.

[0018] This may e.g. provide a cover where the closing of the evacuation channel after use may be more easy and / or consistent.

[0019] In some embodiments, said channel extend over at least a channel length where the width of the evacuation channel is below 1.8 times, such as below 1.5 times, such as below 1.3 times the minimum channel width. The channel width may be determined at the same distance from the major cover surface, e.g. at the major cover surface or at a location between 30-60% of the average height of the solidified solder material from the cover surface.

[0020] In one or more embodiments of the present disclosure, the width of the evacuation channel increases, such as by at least 1.1 times, such as at least 1.2 times, such as at least 1.3 times the minimum channel width along said channel length.

[0021] It has been observed that heat treatment of the solder to obtain the solidified solder material may provide a width increase at some areas of the evacuation channel. This may e.g. help to increase the evacuation performance of the channel while the minimum channel width still enables advantageous closing of the channel when the gap is sealed.

[0022] In one or more embodiments of the present disclosure, the channel width of the respective evacuation channel, at least along a sub-part of said channel length, varies less than 1.7 times, such as less than 1.5 times, such as less than 1.3 times the magnitude of the minimum width of the evacuation channel, wherein said sub-part has a length that is larger, such as at least 1.3 times larger, such as at least 1.5 times larger or at least 1.7 times larger than the magnitude of the minimum channel width, wherein the sub-part overlaps the area of the evacuation channel where the minimum channel width is located. This may provide an advantageous evacuation channel enabling efficient gap evacuation and subsequent sealing of the channel when the gap of the VIG is to be sealed.

[0023] In one or more embodiments of the present disclosure, said solidified glass solder material of the seal material that is configured to be softened to seal the through hole during sealing of the VIG unit gap is omitted at a center area of the major cover surface, or wherein the amount of glass solder seal material at the center area of the major cover surface is reduced, wherein the solidified solder material comprises opposing walls facing a space located opposite to the center area. The center area may be configured to cover the through hole part that provides fluid communication to the gap of the VIG unit assembly to be evacuated. The center area of the cover where the solidified glass solder material is omitted (or reduced) may be configured to cover the through hole. Thus, it may be prevented that solder material from the cover flows into the through hole and / or the gap during sealing of the gap. This may provide a stronger VIG unit and / or a VIG unit providing improved thermal performance. If solder material from the cover enters all the way to the glass sheet at the other side of the gap, the solder material may provide a cold bridge and / or or potential undesired stress conditions in the VIG. This may be prevented by providing a center area as mentioned above.

[0024] Said solidified glass solder material may comprise, such as provide, an inner boundary facing a space opposite a center area of the major cover surface where the surface of the solidified seal material is omitted.

[0025] In one or more embodiments of the present disclosure, said one or more predefined evacuation channels is configured to be in fluid communication with said space between the walls facing the center area when the cover is arranged on a surface so that the surface of the solidified solder material supports on a surface part of a glass sheet of a vacuum insulated glass unit assembly, and so that the covering body, such as said center area, covers at least a part, such as covers a smaller diameter portion, such as covers the entirety of the area of a smaller diameter portion, of a through hole in the glass sheet. This may provide an advantageous cover with advantageous evacuation features. In one or more embodiments of the present disclosure, said center area is larger than the area of the major cover surface at each of the one or more evacuation channels.

[0026] This may enable narrow channels and enable avoiding flow of softened solder material (originating from the solidified solder material) which flows from the from the cover and into the evacuated gap during sealing.

[0027] In one or more embodiments of the present disclosure, the maximum distance between said walls facing the space located opposite to the center area is at least 1.5 times larger, such as at least 2.5 times larger, such as at least 3.5 times larger, than the minimum channel width of each of the one or more predefined evacuation channels.

[0028] This may enable narrow channels and enable avoiding flow of softened solder material (originating from the solidified solder material) which flows from the from the cover and into the evacuated gap during sealing.

[0029] In some embodiments of the present disclosure, the width of the predefined evacuation channel is the width seen when looking towards the surface of the solidified solder material in a direction perpendicular to the major cover surface.

[0030] In some embodiments of the present disclosure, the width of the predefined evacuation channel is at least located between the opposing walls of the solidified solder material facing the evacuation channel, at a location of the opposing walls at a level located between 30-60% of the height, such as average height, above the major cover surface of the solidified seal material and extending in a direction parallel to the major covering surface.

[0031] In one or more embodiments of the present disclosure, the solidified seal material has a height, such as a maximum height, of at least 0.4 mm, such as at least 0.5 mm, such as at least 0.6 mm. This may e.g. enable improved closure of the one or more predefined channels when the gap of the VIG unit assembly is to be sealed. In one or more embodiments of the present disclosure, the solidified seal material has a height, such as a maximum height, of at least 0.7 mm, such as at least 0.8 mm, such as at least 1 mm.

[0032] In one or more embodiments of the present disclosure, the height of the solidified seal material varies by at least 0.1 mm, such as by at least 0.2 mm, such as by at least 0.3 mm over the surface of the solidified solder material facing away from the covering body, for example over the majority of the surface of the solidified solder material facing away from the covering body, thereby causing a surface roughness of the surface of the solidified seal material to form gas passages in the surface of the solder material. Additionally or alternatively, In one or more embodiments of the present disclosure, the height of the solidified seal material varies by at least 10%, such as at least 20% or at least 30% over a width direction of the solidified solder material, thereby causing a surface roughness of the surface of the solidified seal material to form gas passages in the surface of the solder material.

[0033] This may help to enable improved gap evacuation as the gas passages in the surface of the solder material may add on to the evacuation through the one or more predefined channels. Thus e.g. smaller and / or fewer predefined channels may be provided. It may also enable providing a well performing, space saving cover where the final height of the cover after use and including the solder material may be reduced.

[0034] In one or more embodiments of the present disclosure, the surface roughness of the surface of the solidified seal material is obtained as a result of a heating a pre-form of glass solder material arranged at the covering body so as to burn out binder material and soften the solder material, followed by a subsequent cooling of the softened seal material so as to obtain said solidified seal material.

[0035] In one or more embodiments of the present disclosure, said solidified seal material is a solidified seal material that has been obtained from heating a solder material pre-form together with the covering body so as to burn out binder material and soften the solder material, followed by a subsequent cooling of the softened seal material so as to obtain said solidified seal material. In one or more embodiments of the present disclosure, the cover comprises a peripheral seal material residue, the peripheral seal material residue being located at the major cover surface adjacent to a foot region of the solidified solder material, wherein the seal material residue originates from heating of a seal.

[0036] The solder material preform may flow inward, such as shrink, during the heat treatment to obtain the solidified solder material. However, it has been observed that the heat treatment may cause some residue from the solder to remain at the location between the outer boundary of the solidified solder material adjacent to the foot of the solidified seal material, for example when the solder material shrinks when it is heat treated. This residue may be accepted and may even help to provide a subsequent improved wetting between the solder material and the covering body when the solder material of the cover is heated to be softened so as to seal the through hole, and e.g. re-enters the prior position of the solder material pre-form. For example, the residue may be arranged at the major cover surface at the predefined channel.

[0037] In some embodiments, the residue covers at least a major part, such as at least 50%, such as at least 80%, of the area of the major cover surface where the pre-form of the solder material was located initially before the heat treatment, but from where the solder material has retracted due to the heat treatment to obtain the solidified solder material.

[0038] In one or more embodiments of the present disclosure, the cover comprises at least two, such as at least three or at least four of said predefined evacuation channels, each of which predefined channel has a channel width extending between the opposing walls of the solder material.

[0039] This may enable obtaining a cover facilitating improved gap evacuation. Also, more evacuation channels, such as at least two or three predefined evacuation channels, may enable providing more narrow individual predefined channels, helping to collectively enhance gas evacuation, such as helping to reduce flow resistance, while enabling improved and / or more consistent closing of the channel space when the (solidified) solder material is heated to soften it with the purpose of sealing a through hole to seal the evacuated gap of a VIG unit. It is generally understood that the predefined evacuation channel(s) may be intentionally pre-shaped in the solder material preform before obtaining the solidified solder material or after solidifying the solder material by means of e.g. a shaping tool.

[0040] In one or more embodiments of the present disclosure, said predefined evacuation channels, such as at least the inlet thereof (facing the previously mentioned center area), are evenly distributed at the surface of the covering body, such as with substantially similar mutual angle, such as a mutual angle of 180°, 120° or 90°, which angle is measured in the plane of the surface of the covering body.

[0041] In one or more embodiments of the present disclosure, the distance between the opposing walls of the solidified solder material that faces the evacuation channel gradually decreases towards the major cover surface. This may in some further embodiments e.g. provide a funnel shape when seen in a cross sectional view that is transverse to the longitudinal direction of the evacuation channel.

[0042] This may e.g. be provided already at the solder material pre-form or alternatively be provided during heat treating the solder material as e.g. mentioned above in order to obtain the solidified solder material.

[0043] This may e.g. provide a cover where improved and / or more easy closing of the predefined channel(s) may be obtained. It may also provide a solution where less solder material may be needed at the cover.

[0044] In one or more embodiments of the present disclosure, the height of the evacuation channel is at least 30%, such as at least 80%, such as at least 90%, for example substantially 100% of the height of the solidified solder material. In some embodiments said height of the evacuation channel is the evacuation channel height provided when the cover is arranged so that the surface of the solidified solder material supports on a surface part, such as a surface part of a glass sheet surrounding a through hole, such as wherein said height extends perpendicular to said surface part and / or the major cover surface.

[0045] In one or more embodiments of the present disclosure, one or more of the one or more predefined evacuation channels is / are channel(s) that has / have been shaped, such as cut, such as laser cut, mechanically cut or etched, into the surface of the solidified seal. In some further embodiments hereof, the evacuation channel extends, e.g. radially, between an inner side boundary of the solidified solder material and to an exterior side boundary of the solidified solder material.

[0046] Post processing the solder material after it has been solidified may provide several advantages. For example, it may enable making one or more precise, such as small, such as narrow evacuation channels. It may also enable providing a shape of the solder material that ensures a strong connection between the cover and the first glass sheet at the final VIG unit.

[0047] It is generally understood that instead of the channel(s) extending radially, it / they may extend in an at least partly curved shape, such as a spiral shape, or a substantially straight shape which has an inclining angle, such as acute angle to a radial direction from the center of the major cover surface.

[0048] In one or more embodiments of the present disclosure, the surface area of the major cover surface is at least 25 mm2, such as at least 35 mm2, such as at least 40 mm2.

[0049] In one or more embodiments of the present disclosure, the surface area of the major cover surface may be less than 85 mm2, such as less than at least 65 mm2, such as less than 50 mm2. For example, in one or more embodiments of the present disclosure, the surface area of the major cover surface may be in the range of 25 mm2- 85 mm2, such as in the range of 35 mm2- 65 mm2, such as in the range of 40 mm2- 50 mm2.

[0050] This has shown to provide a cover that is small and less visible which provides e.g. an aesthetic advantage. It has also shown to provide a cover that is suitable for use in a through hole of e.g. a thermally tempered glass sheet having a lager and a smaller diameter portion.

[0051] In certain embodiments, the surface area of the major cover surface is between 40 mm2- 45 mm2.

[0052] In one or more embodiments of the present disclosure, the thickness of the covering body, such as a glass covering body, such as a glass disc, is less than 2.4 mm, such as less than 2 mm, such as less than 1 .8 mm. This may e.g. enable a space saving solution. Additionally or alternatively, it may be suitable for use in a stepped through hole comprising a larger and a smaller diameter portion.

[0053] In one or more embodiments of the present disclosure, the thickness of the covering body, such as a glass covering body, such as a glass disc, is larger than 1 mm, such as larger than 1.3 mm, such as larger than 1.4 mm.

[0054] This may e.g. provide a strong cover.

[0055] In one or more embodiments of the present disclosure, the thickness of the covering body is between 1 mm and 2.4 mm, such as between 1.3 mm and 2.3 mm, such as between 1.7 mm and 2.2 mm (endpoints included). In certain embodiments, the thickness of the covering body may be between 1.5 mm and 1.7 mm, such as substantially 1.6 mm.

[0056] In one or more embodiments of the present disclosure, the thickness of the covering body is between 1.5 mm and 2.4 mm, such as between 1.7 mm and 2.2 mm, such as between 1.9 mm and 2.2 mm (endpoints included). This may e.g. provide a cover which is sufficiently strong and also is space saving.

[0057] In certain embodiments, the thickness of the covering body may be between 1.9 mm and 2.1 mm, such as substantially 2 mm.

[0058] In one or more embodiments of the present disclosure, the covering body is substantially circular and has a diameter of at least 4 mm, such as at least 5 mm, such as at least 6.5 mm.

[0059] In one or more embodiments of the present disclosure, the covering body is substantially circular and has a diameter of less than 12 mm, such as less than 10 mm, such as less than 9 mm. In one or more embodiments of the present disclosure, the covering body is substantially circular and has a diameter in the range of 4 mm - 12 mm, such as in the range of 5 mm - 10 mm, such as in the range of 6.5 mm - 9 mm (endpoints included).

[0060] This may e.g. provide a cover that is suitable for use in a larger diameter portion of a stepped through hole. In some embodiments of the present disclosure, the covering body has a diameter in the range of 7 mm - 9 mm, such as in the range of 7.2-7.8 mm.

[0061] In one or more embodiments of the present disclosure, the covering body comprise or consist of a glass body, such as a structural glass body, such as an annealed glass body or an hardened glass body. A cover with a glass body may e.g. be beneficial e.g. due to that is has a coefficient of thermal expansion that is close to that of the glass sheet of the VIG unit assembly. Also it may enable reducing the size, such as diameter of a larger diameter portion of the through hole when compared to the maximum covering body width, such as covering body diameter.

[0062] In one or more embodiments of the present disclosure, the total volume of said solidified solder material at the major cover surface is at least 6 mm3, such as at least 8 mm3, such as at least 10 mm3. It has by tests been seen that such an amount of solidified glass solder material may be advantageous for closing one or more predefined channels of an evacuated gap, and enable sealing around a through hole (e.g. smaller diameter portion) having a diameter

[0063] In one or more embodiments of the present disclosure, the total volume of said solidified solder material at the major cover surface is less than 30 mm3, such as less than 20 mm3, such as less than 15 mm3. This may e.g. enable a more controlled sealing of the through hole.

[0064] In one or more embodiments of the present disclosure, the total volume of said solidified solder material at the major cover surface is in the range of 6 - 30 mm3, such as in the range of 6 - 18 mm3, such as in the range of 8 - 15 mm3.

[0065] It is understood that said total volume of the solidified solder material excludes a primer, if a primer is present at the cover.

[0066] In one or more embodiments of the present disclosure, the height of the evacuation channel is at least 0.5 mm, such as at least 0.7 mm, such as at least 0.9 mm.

[0067] In one or more embodiments of the present disclosure, the minimum cross sectional area of each of the one or more channels, such as at the narrowest part of the channel, is less than 3 mm2, such as less than 2.5 mm2, such as less than 1.5 mm2. The cross sectional area may extend substantially perpendicular to the longitudinal direction of the evacuation channel. This may e.g. in some further embodiments be determined when the cover is arranged so that the surface of the solidified solder material supports on a surface of a glass sheet.

[0068] In one or more embodiments of the present disclosure, the minimum cross sectional area of each of the one or more channels, such as at the narrowest part of the channel, is at least 0.08 mm2, such as at least 0.1 mm2, such as at least 0.2 mm2. The cross sectional area may extend substantially perpendicular to the longitudinal direction of the evacuation channel. This may e.g. in some further embodiments be determined when the cover is arranged so that the surface of the solidified solder material supports on a surface of a glass sheet.

[0069] In one or more embodiments of the present disclosure, the minimum cross sectional area of each of the one or more channels, such as at the narrowest part of the channel, is in the range of 0.08 - 3 mm2, such as in the range of 0.1 - 2.5 mm2, such as in the range of 0.2 -1.5 mm2. The cross sectional area may extend substantially perpendicular to the longitudinal direction of the evacuation channel. This may e.g. in some further embodiments be determined when the cover is arranged so that the surface of the solidified solder material supports on a surface of a glass sheet.

[0070] This may provide a cover solution that may help to provide a consistent and / or space saving sealing of the evacuated gap by sealing the through hole.

[0071] In one or more embodiments of the present disclosure, the minimum cross sectional area of each of the one or more channels, such as at the narrowest part of the channel, is in the range of 0.4 - 0.9 mm2, The cross sectional area may extend substantially perpendicular to the longitudinal direction of the evacuation channel. This may e.g. in some further embodiments be determined when the cover is arranged so that the surface of the solidified solder material supports on a surface of a glass sheet.

[0072] This may e.g. help to provide an efficient gap evacuation In one or more embodiments of the present disclosure, the evacuation channel height, such as the minimum height, is larger than the width, such as the minimum width, of the evacuation channel.

[0073] This may e.g. help to provide a narrow channel that is more easy to close while, e.g. with a reduced amount of solder material. Reducing the amount of solder material may e.g. help to provide a space saving solution and / or a solution where the flow of the solder material when sealing the gap is more controlled.

[0074] In one or more embodiments of the present disclosure, the evacuation channel height, such as minimum evacuation channel height, may be within ±70%, such as within ±50%, such as within ±30% of the evacuation channel width, such as the minimum evacuation channel width.

[0075] In one or more embodiments of the present disclosure, the solidified solder material comprises at least one portion of solder material, such as at least two portions of solder material separated by predefined evacuation channels, such as wherein the minimum width of the solidified solder material portion(s), excluding the area of the one or more evacuation channels 23, is at least 1.4 mm, such as at least 1.6 mm, such as at least 1.8 mm.

[0076] This may provide a solution where the cover enables efficient and controlled closing of the through hole when the gap has been evacuated.

[0077] In one or more embodiments of the present disclosure, one or more gas passages in the surface of the solidified glass solder material of the cover may be provided as a consequence of a surface roughness of the surface of the solidified solder material, wherein said one or more gas passages are separate to the one or more predefined evacuation channels. In some further embodiments hereof, said surface roughness of the solidified seal material surface may be provided by means of protrusions at / in the surface of the seal material of the cover, wherein said protrusions are arranged staggered and / or substantially randomly, across the surface of the glass solder material. This may provide a cover that may be placed and where improved gas flow may be obtained, e.g. due to that the combination of the one or more predefined channels and the gas passages reduces the flow resistance during evacuation. Hence, prior to heating the solidified seal material of the cover to soften it in order to provide an hermetically sealed, evacuated gap of a VIG unit, the surface roughness of the seal material may help to provide gas channels between a glass surface and the seal material. These channels may be used for evacuating gas from the gap of the VIG unit assembly.

[0078] In one or more embodiments of the present disclosure, the surface roughness of the surface of the solidified seal material which faces said surface part of the first glass sheet is above 10 pm, such as above 25 pm, such as above 35 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0079] The surface roughness may be defined along a sampling length corresponding to the full length, such as defined by the circumference, of the solidified seal material at the top of the solidified seal material. This may in practice be defined along an envisaged circle which is concentric with the solidified solder material, if the solder material provides the shape or contour of a ring, and which has a diameter providing that the circle is arranged substantially midways between the outer and inner periphery of the solidified solder material. The surface roughness may e.g. be determined by means of a profilometer or a laser scanner.

[0080] The Ra surface roughness parameter may define, within the sampling length, the average roughness of the solidified seal material surface, e.g. including the deviations from the mean line. The Rz surface roughness parameter may define the difference between the highest peak and lowest valley within the sampling length. It may define the maximum height of the profile.

[0081] Surface roughness may be defined according to ISO 21920, such as ISO 21920-2.

[0082] In one or more embodiments of the present disclosure, said surface roughness of the surface of the solidified seal material may be obtained as a result of a pre-heating of the seal material of the cover, and a subsequent cooling, such as pre-cooling of the softened seal material so as to solidify the seal material.

[0083] It has been observed that the heat treatment of the solder material to obtain the solidified solder material may provide a solidified glass solder material that is both advantageous for use during sealing of the gap when it has been evacuated, e.g. due to reduced risk of contamination during sealing of the gap, and moreover the surface roughness may provide advantageous gas passages.

[0084] The pre-cooling and pre-heating are understood as steps provided before the final heating and cooling of the solder material in order to seal the evacuated gap.

[0085] In one or more embodiments of the present disclosure, said surface roughness of the solidified seal material surface of the cover is the surface roughness over at least 80%, such as at least 90%, such as at least 95%, or at least 98%, of the surface area of the solidified seal material surface which is unbonded to the surface of the covering body.

[0086] In one or more embodiments of the present disclosure, one or more of the one or more predefined evacuation channels is a channel that has been shaped, such as by means of a shaping tool, after the solder material has solidified, such as after the solder material has been heated to be softened and then cooled so as to solidify the softened solder material.

[0087] A separate step of shaping the solidified seal material may provide a more precise and / or an optimized shape of the solidified seal material before the step of evacuating and sealing the gap of the VIG unit.

[0088] In one or more embodiments of the present disclosure, one or more of the one or more predefined evacuation channels is a channel that originates from a pre-shaped channel provided in the solder material pre-form prior to solidifying said solder material. In further embodiments hereof, said solidifying of the solder material comprises the steps of heating the solder material to e.g. obtain binder burnout and to soften the solder material, and then cooling the solder material so as to solidify the softened solder material. In one or more embodiments of the present disclosure, the covering body comprises or is a glass disc, such as a circular glass disc.

[0089] This has shown to e.g. provide a cost efficient and space saving cover. The disk may or may not comprise one or more manufactured protrusions and / or gaps, for example for use for positioning the cover as desired and / or for improved gas flow, at the covering body side surface.

[0090] In one or more embodiments of the present disclosure, the covering body comprises or consist of a glass body such as a structural glass body, such as an annealed glass body.

[0091] A glass body may provide desired advantages, such as temperature resistance and / or improved matching of coefficient of thermal expansion CTE with the CTE of the seal material of the cover comprising glass solder material.

[0092] In one or more embodiments of the present disclosure, the amount of binder material in the solidified seal material is below 2 wt%, such as below 1 wt% or below 0.1 wt%.

[0093] This seal material may reduce subsequent outgassing and / or provide a strong seal when using the solidified seal material of the cover for sealing the evacuated gap of the VIG unit by sealing the through hole.

[0094] In one or more embodiments of the present disclosure, the amount of solvent in the solidified seal material is below 2 wt%, such as below 1 wt% or below 0.2 wt%.

[0095] This seal material may reduce subsequent outgassing and / or provide a strong seal when using the solidified seal material of the cover for sealing the evacuated gap of the VIG unit by sealing the through hole.

[0096] In one or more embodiments of the present disclosure, the cover is configured so that when the cover is arranged so that when the surface of the solidified solder material supports by means of gravity on an upwardly facing surface part (such as a plane substantially smooth surface) the average flow resistance in the area from the center area (such as the above mentioned center area) of the cover, and past the solidified solder material to the outer periphery of the cover, determined in seconds per liter (s / L), is less than 10 (s / L), such as less than 8 s / L, such as less than 4 s / L.

[0097] This may help to obtain a cover that is suitable for use during evacuating the gap of a larger VIG unit, such as a VIG unit for a building window, a refrigerator door / lid and / or the like.

[0098] In one or more embodiments of the present disclosure, the cover is configured so that when the cover is arranged so that when the surface of the solidified solder material supports by means of gravity on an upwardly facing surface part (such as a plane substantially smooth surface) surrounding a through hole of a glass sheet of a VIG unit assembly, the average flow resistance in the area from the through hole, and past the solidified solder material to the outer periphery of the cover, determined in seconds per liter (s / L), is less than 10 (s / L), such as less than 8 s / L, such as less than 4 s / L.

[0099] This may help to obtain a cover that is suitable for use during evacuating the gap of a larger VIG unit, such as a VIG unit for a building window, a refrigerator door / lid and / or the like.

[0100] It is generally understood that even though the surface roughness of the glass sheet surface on which the solder material of the cover may support in some embodiments may be shaped to have a surface roughness improving gap evacuation, the surface of the glass sheet surface on which the solder material of the cover may support may in other embodiments be smoothened, such as polished or the like to obtain a more smooth surface, e.g. for improved bonding.

[0101] In one or more embodiments of the present disclosure, the solidified glass solder material covers at least 55%, such as at least 59%, of the area of the major cover surface. In one or more embodiments of the present disclosure, the solidified glass solder material covers at least 65%, such as at least 71 %, of the area of the major cover surface. In one or more embodiments of the present disclosure, the solidified glass solder material covers less than 100%, such as less than 95%, such as less than 85% of the area of the major cover surface.

[0102] In one or more embodiments of the present disclosure, the solidified glass solder material covers between 40% and 100%, such as between 50% and 90%, such as between 50% and 73%, of the area of the major cover surface.

[0103] In one or more embodiments of the present disclosure, the thickness of the covering body, such as a glass body, is between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm, such as between 1.8 mm and 2.1 mm, endpoints included.

[0104] In one or more embodiments of the present disclosure, one or more of said one or more evacuation channels constitutes a discontinuation. This discontinuation may e.g. be provided in the pre-form of solder frit material, or it may be obtained later on by e.g. a shaping tool after solidification of the solder material.

[0105] A discontinuation may e.g. enable obtaining a larger cross sectional area of the channel while keeping the channel more narrow.

[0106] In one or more embodiments of the present disclosure, the distance between the opposing walls of the solidified solder material facing the predefined channel gradually increase along the length of the evacuation channel from a minimum channel width.

[0107] This may e.g. provide a solder material shape that both enables efficient gap evacuation and which may be advantageous when the channel is to be sealed to seal the evacuated gap.

[0108] In one or more embodiments of the present disclosure, the opposing walls of the solidified solder material that faces the predefined channel may be convexly shaped so that the width of the evacuation channel(s) gradually increase from the minimum channel width along the length of the evacuation channel. In one or more embodiments of the present disclosure, the seal material moreover comprises a primer layer, such as a single primer layer or a multilayer primer layer, arranged between the solder material and the covering body.

[0109] This may e.g. provide an improved cover. The primer layer may e.g. act as absorbers during the local heating of the solder material. Additionally or alternatively, the primer layer(s) may provide a better match between properties, such as glass transition temperature and / or thermal expansion coefficient of the covering body and the solder material. Additionally or alternatively, the primer layer may allow the construction of a more inexpensive VIG unit as glass frit used for primer may be less expensive than the solder material. Additionally or alternatively, the amount of undesired materials, such as toxic material(s) at the covering body may be reduced, and / or a wider range of solder material types may be used for primer. It is generally understood that the one or more primer layers may comprise a single layer primer layer or a multi layer primer layer comprising at least two, such as at least three primer layers, e.g. made from glass solder material having different desired properties, e.g. relating to thermal expansion coefficient and / or glass transition temperature. In some embodiments, however, just one primer layer may be provided.

[0110] It is however understood that in other embodiments, the seal at the cover may not comprise (a) primer(s).

[0111] In one or more embodiments, the primer layer is arranged so as to cover substantially the whole major surface of the covering body.

[0112] According to one or more embodiments, the primer layer(s) may have a glass transition temperature between the glass transition temperature Tg of the covering body and the glass transition temperature of the solder material. According to one or more embodiments, the primer layer(s) may have a softening temperature, such as Littleton temperature, between the softening temperature, such as Littleton temperature, of the covering body and the softening temperature, such as Littleton temperature, of the solder material.

[0113] The primer layer at the cover may be arranged on the major surface of the covering body so as to cover at least the same area as the solder material covers. For example, this may result in a cover where the primer layer is or is not visible when the cover is viewed from the side of the solder material. Alternatively, the primer layer may be arranged so as to cover a larger area than the solder material.

[0114] The primer layer may be efficiently heated during the step of softening, such as locally heating, the solder material so as to seal the through hole after evacuating the gap. The heater may also heat the primer layer material at the channel (if present). Having a primer layer across the channels may help to provide a heated and thus more susceptible base for the softened solder material to flow across when sealing the evacuated gap and thus removing the channel(s) after the channel(s). This may provide an improved design where the predefined channels are more easily closed during the softening and heating step.

[0115] In one or more embodiments, the primer layer is arranged so as to cover at least the same area of the major surface of the covering body as is covered by the seal material.

[0116] In one or more further embodiments, the primer layer is arranged so as to cover the whole major surface of the covering body, e.g. except a center area, such as wherein the primer layer forms a ring around the center area.

[0117] For example, the primer layer may in some embodiments be arranged across substantially the entire major surface of the covering body at the solder side of the cover. In yet another embodiment, the primer layer may be omitted at desired areas of the covering body surface. For example, in some embodiments, a center area of the covering body surface may be designed so as to be free from primer layer as well as solder material. This may e.g. help to provide an improved barrier that may reduce the risk of the softened solder material flowing into the through hole during the sealing of the through hole.

[0118] The primer layer at the cover may in some embodiments cover the major part of the surface of the covering body except the center area, for example providing a continuous stretch, such as ring, of material across any predefined evacuation channels provided in the seal material. It is generally understood that in one or more embodiments, the primer layer may have a height in the range of 10 - 100 pm, such as in the range of 20 - 80 pm, such as in the range of 30 - 50 pm, and / or wherein the primer layer has a height of at least 10 pm, such as at least 20 pm, such as at least 30 pm, and / or wherein the primer layer has a height of no more than 100 pm, such as no more than 80 pm, such as no more than 50 pm.

[0119] In one or more embodiments, the primer layer comprises a material with a glass transition temperature Tg that is lower than the glass transition temperature of the covering body and higher than the glass transition temperature of the seal material.

[0120] In one or more embodiments, the primer layer covers between 50% and 100%, such as between 70% and 100%, such as between 70% and 93% of the major surface of the covering body.

[0121] In one or more embodiments, the primer layer covers an area that is larger, such as at least 5% larger, such as at least 15% larger or at least 20% larger than the area covered by the solidified solder material.

[0122] It is generally understood that in one or more embodiments of the present disclosure, the first glass sheet may additionally or alternatively comprise a primer layer at the first glass sheet so that this primer is placed between the first glass sheet and the solidified seal material of the cover, so as to bond with the solidified seal material of the cover when this is heated and softened so as to seal the evacuated gap by sealing the evacuation hole. This may e.g. help to enable providing an improved sealing of the evacuated gap and / or help to obtain an improved manufacturing process for sealing the gap.

[0123] In one or more embodiments of the present disclosure, the solidified glass solder material comprises one or more inorganic oxides selected from the group of oxides of Li, B, Na, Mg, Al, Si, P, K, V, Mn, Zn, Rb, Ag, Sn, Te, Ba and / or Bi. In some embodiments, the glass seal material comprises one or more oxides of Te and / or V, such as comprising one or more of V2O5, VO2, and / or V2O3 in combination with TeC>2, TeCL, TeCh, and / or TesCL. These oxides may be known in various combinations as low-temperature solder glass materials. Tellurium / Vanadium (Te / V) low-temperature glass solder materials may have a glass transition temperature and melting temperature substantially lower than the corresponding values for soda-lime glass. For example, Te / V solder glass materials may have glass transition temperature and melting temperature below the range of temperatures, where thermally tempered soda-lime glass is known to quickly detemper. For example, the Te / V-based solder glass material disclosed in US 2024 / 0167328 A1 has a glass transition temperature of 290 °C and a melting point temperature of 390 - 395 °C.

[0124] In one or more embodiments of the present disclosure, the solidified glass solder material (22) comprises more tellurium oxide than vanadium oxide by weight.

[0125] In one or more embodiments of the present disclosure, the solidified glass solder material (22) additionally comprises one or more of AI2O3, SiC>2, MgO, P2O5, Bi20s, ZnO, Nb2C>5, Ag2O, and / or MnO.

[0126] Additives, such as additional oxides, may help to adjust the properties of the solder glass material to better suit the requirements of a given application, such as for sealing the through hole of a vacuum-insulated glass unit.

[0127] In one or more embodiments of the present disclosure, the solidified glass solder material (22) comprises Bi2C>3,such as in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0128] Bismuth (Bi)-based solder glass materials are considered less toxic or non-toxic alternatives to e.g. lead (Pb)-containing compositions or Te / V glass solder materials. Known Bi-based solder glass materials have a higher glass transition temperature and melting temperature than e.g. Te / V materials.

[0129] In one or more embodiments of the present disclosure, the solder material comprises B2O3 in combination with one or more of the following metal oxides: SiC>2, Bi20s, ZnO, and / or AI2O3. In a further embodiment, the solder material is characterized by a B:Bi ratio of at least 2, such as at least 2.5. Boron (B)-based solder glass materials have been described in prior art as non-toxic alternatives to e.g. lead (Pb)-containing compositions or Te / V glass solder materials. Known B-based solder glass materials have a higher glass transition temperature and melting temperature than e.g. Te / V materials.

[0130] In one or more embodiments of the present disclosure, the solder material comprises SnO and P2O5. In a further embodiment, the solder material comprises at least 50 wt-% SnO. In one or more embodiments of the present disclosure, the solder material comprises SnO and P2O5 in combination with ZnO.

[0131] In one or more embodiments of the present disclosure, the solder material comprises less than 1 wt-%, such as less than 0.5 wt-%, such as less than 0.1 wt-% of Pb and V.

[0132] Toxic metals may pose a potential undesired hazard throughout the lifetime of the vacuum-insulated glass unit from the human beings involved in the production, to the environment surrounding the VIG unit once it is installed in its designated location, and until it is disassembled and its constituent materials recycled and / or scrapped and during scrapping of the VIG unit. Thus, in order to protect both workers and / or the environment, it may be desirable to avoid or reduce the use of toxic materials.

[0133] Soda-lime glass has a glass transition temperature in the range of 520 - 600 °C. Thus, in order to reduce or avoid de-tempering and / or deforming the two glass sheets, it is advantageous to use a solder glass material that is characterized by a glass transition temperature below that of soda-lime glass. This helps to allow the temperature during the sealing process to remain below the glass transition temperature of the soda-lime glass. Some tests suggest that the higher the glass sheet temperature gets above 360 °C, the faster the de-tempering process occurs.

[0134] In one or more embodiments of the present disclosure, the solder material has a glass transition temperature Tg, such as a rated glass transition temperature, higher than 300 °C, such as higher than 320 °C. In one or more embodiments of the present disclosure, the solder material has a glass transition temperature Tg, such as a rated glass transition temperature, higher than 340 °C, such as higher than 350 °C.

[0135] The glass transition temperature may be found by means of differential scanning calorimetry (DSC) and / or thermal expansion measurements, in both cases where a more or less sharp kink occurs when heating or cooling the material above or below the glass transition temperature. Additionally or alternatively, the glass transition temperature may be provided by the manufacturer as a rated glass transition temperature.

[0136] In one or more embodiments of the present disclosure, the solder material has a glass transition temperature Tg lower than 400 °C, such as lower than 390 °C, such as lower than 380 °C.

[0137] In one or more embodiments of the present disclosure, the solder material has a glass transition temperature Tg in the range of 280 - 400 °C, such as in the range of 290 - 390 °C, such as in the range of 330-380 °C.

[0138] In one or more embodiments of the present disclosure, the solder material has a glass transition temperature Tg in the range of 340- 400 °C, such as in the range of 350 - 390 °C, such as in the range of 359-380 °C.

[0139] In one or more embodiments of the present disclosure, the solder material has a melting temperature Tm higher than 400 °C, such as higher than 420 °C, such as higher than 450 °C.

[0140] In one or more embodiments of the present disclosure, the Littleton softening point Ts of the solder material may be within 380-470 °C, such as within 390-450 °C, such as within 410-440 °C.

[0141] In order to ensure a lower degree of de-tempering of the glass sheets at the through hole, it may be relevant to limit the time which the solder material is heated to elevated temperatures, such as temperatures in the vicinity of the glass transition temperature Tg of soda-lime glass, which marks the point where the de-tempering rate becomes high. For example, it may be advantageous to limit the time during which the solder material 22 is warmer than 360°C, and especially warmer than 400°C or 430 °C.

[0142] In one or more embodiments of the present disclosure, the solder material comprises a solder base material, such as a solder base material according to the previously disclosed aspects or embodiments of the present disclosure, and an amount of filler particles, such as particles with a glass transition temperature Tg higher than the glass transition temperature Tg of the solder base material.

[0143] Filler particles may be added to the solder material in order to provide structural integrity to the solder layer during and after the manufacturing process. Additionally or alternatively, filler particles may be added to adjust the thermal expansion coefficient of the solder layer, for example to better match the thermal expansion of soda-lime glass.

[0144] In one or more embodiments of the present disclosure, the filler particles consist of or comprise an inorganic oxide, such as a ceramic material. In a further embodiment, at least 90% of the filler particles have a diameter in the range of 0.1 - 100 pm, such as in the range of 5 - 50 pm, such as in the range of 10 - 40 pm.

[0145] As mentioned above and / or below, according to various embodiments and / or aspects of the present disclosure, the cover may comprise a covering body and a major cover surface at a solder side of the cover. The cover comprises a seal material comprising a glass solder material at the solder side. The glass transition temperature of the glass solder material is lower than the glass transition temperature of the covering body. The seal material may moreover comprise a primer layer, such as a single primer layer or a multilayer primer layer, arranged between the solder material and the covering body.

[0146] The primer layer may e.g. act as absorbers during the local heating of the solder material. Additionally or alternatively, the primer layer(s) may provide a better match between properties, such as glass transition temperature and / or thermal expansion coefficient of the covering body and the solder material. Additionally or alternatively, the primer layer may allow the construction of a more inexpensive VIG unit as glass frit used for primer may be less expensive than the solder material. Additionally or alternatively, the amount of undesired materials, such as toxic material(s) at the covering body may be reduced, and / or a wider range of solder material types may be used for primer. It is generally understood that the one or more primer layers may comprise a single layer primer layer or a multi layer primer layer comprising at least two, such as at least three primer layers, e.g. made from glass solder material having different desired properties, e.g. relating to thermal expansion coefficient and / or glass transition temperature. In some embodiments, however, just one primer layer may be provided.

[0147] It is understood that in other embodiments, the seal at the cover may not comprise (a) primer(s).

[0148] In one or more embodiments, the primer layer is arranged so as to cover substantially the whole major surface of the covering body.

[0149] According to one or more embodiments, the primer layer(s) may have a glass transition temperature between the glass transition temperature Tg of the covering body and the glass transition temperature of the solder material.

[0150] According to one or more embodiments, the primer layer(s) may have a softening temperature, such as Littleton temperature, between the softening temperature, such as Littleton temperature, of the covering body and the softening temperature, such as Littleton temperature, of the solder material.

[0151] The primer layer at the cover may be arranged on the major surface of the covering body so as to cover at least the same area as the solder material covers. For example, this may result in a cover where the primer layer is or is not visible when the cover is viewed from the side of the solder material. Alternatively, the primer layer may be arranged so as to cover a larger area than the solder material.

[0152] The primer layer may be efficiently heated during the step of softening, such as locally heating, the solder material so as to seal the through hole after evacuating the gap.

[0153] The heater may also heat the primer layer material at the channel (if present). Having a primer layer across the channels may help to provide a heated and thus more susceptible base for the softened solder material to flow across when sealing the evacuated gap and thus removing the channel(s) after the channel(s). This may provide an improved design where the predefined channels are more easily closed during the softening and heating step.

[0154] In one or more embodiments, the primer layer is arranged so as to cover at least the same area of the major surface of the covering body as is covered by the seal material.

[0155] In one or more further embodiments, the primer layer is arranged so as to cover the whole major surface of the covering body, e.g. except a center area, such as wherein the primer layer forms a ring around the center area.

[0156] For example, the primer layer may in some embodiments be arranged across substantially the entire major surface of the covering body at the solder side of the cover. In yet another embodiment, the primer layer may be omitted at desired areas of the covering body surface. For example, in some embodiments, a center area of the covering body surface may be designed so as to be free from primer layer as well as solder material. This may e.g. help to provide an improved barrier that may reduce the risk of the softened solder material flowing into the through hole during the sealing of the through hole.

[0157] The primer layer at the cover may in some embodiments cover the major part of the surface of the covering body except the center area, for example providing a continuous stretch, such as ring, of material across any predefined evacuation channels provided in the seal material.

[0158] In one or more embodiments, the primer layer has a height in the range of 10 - 100 pm, such as in the range of 20 - 80 pm, such as in the range of 30 - 50 pm, and / or wherein the primer layer has a height of at least 10 pm, such as at least 20 pm, such as at least 30 pm, and / or wherein the primer layer has a height of no more than 100 pm, such as no more than 80 pm, such as no more than 50 pm.

[0159] In one or more embodiments, the primer layer comprises a material with a glass transition temperature Tg that is lower than the glass transition temperature of the covering body and higher than the glass transition temperature of the seal material. In one or more embodiments, the primer layer covers between 50% and 100%, such as between 70% and 100%, such as between 70% and 93% of the major surface of the covering body.

[0160] In one or more embodiments, the primer layer covers an area that is larger, such as at least 5% larger, such as at least 15% larger or at least 20% larger than the area covered by the solidified solder material.

[0161] In some further or additional aspects of the prese4nt disclosure, the first glass sheet may additionally or alternatively comprise a primer layer at the first glass sheet so that this primer is placed between the first glass sheet and the solidified seal material of the cover, so as to bond with the solidified seal material of the cover when this is heated and softened so as to seal the evacuated gap by sealing the evacuation hole.

[0162] In one or more embodiments of the present disclosure, one or both of the above mentioned primers may comprise one or more inorganic oxides, such as at least 50 wt- % of one or more inorganic oxides.

[0163] In one or more embodiments of the present disclosure, each of the one or two primers comprises a mixture of oxides, such as oxides chosen from Li, B, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Zn, Zr, Mo, Sn, Pb, and / or Bi oxides.

[0164] In one or more embodiments of the present disclosure, each of the one or two primers, comprises Bi, such as Bi20a. In a further embodiment, one or both of the one or two primer layers comprise at least 40 wt-%, such as at least 50 wt-% Bi20a.

[0165] In one or more embodiments of the present disclosure, one or both of the one or two primer layers comprise Bi20a in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0166] In one or more embodiments of the present disclosure, one or both of the one or two primer layers comprise Bi, such as Bi20s in combination with Na2O and SiC>2.

[0167] In one or more embodiments of the present disclosure, one or both of the one or two primer layers (if present) additionally comprise at least one pigment, such as a compound, such as an oxide, containing one or more of C, Fe, Cr, Mn, Co, Ni, and / or Cu, such as a Cu / Cr spinel. According to a further embodiment, the concentration of pigment is in the range of 0.1-15 wt-%, such as in the range of 1-10 wt-%, such as in the range of 2-5 wt-%.

[0168] Common absorptive pigments include carbon black and various transition metal compounds, such as copper chromite (Cu2Cr2O4), which adopts the spinel crystal structure. These pigments may absorb substantially across the entire visible spectrum (appearing black) or they may have discrete or localized absorption bands (appearing coloured). Additionally, the pigments may reflect parts or all of the visible spectrum (appearing white or mirror-like). Similarly, the pigments may absorb or reflect substantially all the near infrared spectrum, or they may have discrete or localized absorption bands in the near infrared range.

[0169] The pigment concentration may be selected to be high enough to supply the primer material with suitable optical absorption and / or reflection properties. Such properties may e.g. be used during heating and softening of the solder material by means of one or more heating beams as e.g. previously described. The desired pigment concentration may depend on the primer thickness in the glass sheet assembly during the step of heating the seal. If, for example, the primer layer is very thick, the pigment concentration may be decreased while still obtaining a high absorption of the one or more heating beams. Meanwhile, a thin primer layer may require a high concentration of pigment to achieve a suitable heating energy absorption.

[0170] In one or more embodiments of the present disclosure, the one or two primer layers comprise less than 1 wt-%, such as less than 0.5 wt-%, such as less than 0.1 wt-%, of Pb and V.

[0171] In one or more embodiments of the present disclosure, the one or two primer layers comprise a primer base material according to the previously disclosed aspects and an amount of filler particles, such as particles with a glass transition temperature higher than the glass transition temperature of the primer base material.

[0172] Filler particles may be added to the primer solder material in order to provide structural integrity to the primer layer during and after the manufacturing process. Additionally or alternatively, filler particles may be added to adjust the thermal expansion coefficient of the primer layer, for example to better match the thermal expansion of soda-lime glass and / or the solder material used in the seal.

[0173] In one or more embodiments of the present disclosure, the filler particles consist of or comprise an inorganic oxide, such as a ceramic material. In a further embodiment, at least 90% of the filler particles have a diameter in the range of 0.1 - 30 pm, such as in the range of 1 - 20 pm, such as in the range of 5 - 10 pm.

[0174] According to one or more embodiments of the present disclosure, one or both primer layers (on cover and / or glass sheet of VIG unit assembly) as e.g. previously disclosed may have a glass transition temperature between the glass transition temperature Tg of the glass sheet I covering body and the glass transition temperature of the solder material. Above the glass transition temperature, the molecular mobility of the material increases, which makes it more soft and more easily deformable. This may provide a means for building a seal with strong connections between each of the abutting layers, such that each primer layer is bonded strongly to the glass sheet or the covering body as well as to the solder material. For example, the one or two primer layers may be bonded to a glass sheet at a temperature above the glass transition temperature of both the primer layer material and the glass of the glass sheet at which it is applied. This may e.g. be done during a thermal tempering process for thermally tempering the glass sheets prior to assembling the glass sheet assembly, and / or a process to provide an advantageous primer on a covering body workpiece. At this temperature, the molecular mobility of both the primer layer material and the glass is increased such that the two materials may conform to the interface surface topography and / or flow into each other in an interface area so as to provide a strong bond.

[0175] Similarly, during the process of sealing the through hole of the VIG unit assembly / glass sheet assembly, the primer layer or layers (if present) and solder material may by means of one or more laser light beams or the like (e.g. in combination with a preheating) be heated to a temperature above the glass transition temperature of both of them so that a similarly strong bond may be formed between the solder material and each of the one or two primer layers. The temperature may here be maintained below the glass transition temperature of the glass sheet. Additionally or alternatively, each of the primer layer material(s) (if present) may in some embodiments have a (e.g. rated) thermal expansion coefficient between that of the glass of the glass sheets, such as soda-lime glass (8.5-9.3 ppm / K), and the thermal expansion coefficient of the solder material. In this case, the respective single layer or multi-layer primer layer(s) may provide an intermediate connection between the solder material and the glass sheet and / or covering body and solder material that bridges the thermal expansion coefficient so as to e.g. alleviate and distribute stresses connected with temperature changes in the final VIG unit. This may be relevant, since the process of sealing the through hole of the VIG unit comprises heating the solidified seal so as to soften it. Thus, during the cooling back down to room temperature, such as 20 °C, the seal may contracts due to the gradual alleviation of the effect of the thermal expansion. If there were to be a larger difference between the thermal expansion coefficient of the solder material and the glass sheet and / or covering body, the interface between them may be more prone to shear stresses and may break due to the varying thermal contraction during this cooling process.

[0176] Additionally or alternatively, both the primer layer(s) and the solder material may have a thermal expansion coefficient close to that of the glass in the glass sheet I covering body, such as deviating less than 15%, such as less than 10%, such as less than 5% from the thermal expansion coefficient of the glass of the glass sheet I covering body. In for example that case, it may be less relevant to select the primer material to have thermal expansion coefficient between that of the solder material and the glass of the glass sheet I covering body.

[0177] In one or more embodiments of the present disclosure, one or both of the one or two primer layers has a glass transition temperature higher than 300 °C, such as higher than 320 °C, such as higher than 350 °C.

[0178] In one or more embodiments of the present disclosure, one or both of the one or two primer layers has a glass transition temperature higher than 400 °C, such as higher than 430 °C, such as higher than 480 °C.

[0179] In one or more embodiments of the present disclosure, one or both of the one or two primer layers have a glass transition temperature lower than 480 °C, such as lower than 450 °C. In one or more embodiments of the present disclosure, one or both of the one or two primer layers has a glass transition temperature in the range of 300 - 480 °C, such as in the range of 310 - 450 °C, such as in the range of 340 - 400 °C.

[0180] In one or more embodiments of the present disclosure, one or both of the one or two primer layers may have a melting temperature (Tm) higher than 450 °C, such as higher than 480 °C, such as higher than 500 °C.

[0181] It is generally understood that the primer(s) of the seal remains harder than the solder material, such as substantially un-softened, during substantially the entire heating of the solder material by means of the one or more heating beams such as laser light beams to seal the evacuated gap.

[0182] It is generally understood that in some embodiments of the present disclosure, the step of heating and softening the solder material by means of the one or more heating beams may be preceded by a step of affixing the one or more primer layers onto a glass sheet I covering body, such as during thermal tempering of said glass sheet.

[0183] In order to obtain a strong through hole sealing, the primer layers may be bonded to the glass sheet at a temperature higher than that necessary to soften the solder material of the seal. In one or more embodiments of the present disclosure, the step of bonding the one or more primer layers to the glass sheets may coincide with the step of thermally tempering the glass sheets. Here, the glass sheets are heated to a temperature above their glass transition temperature, whereafter they are quench- cooled thus trapping compressive stresses in the surfaces of the glass sheets. By utilizing the heating in this step for simultaneously affixing the one or more primer layers, production is simplified and made more cost-efficient.

[0184] It is generally understood that the glass solder material types mentioned above may be used for the seal material of the cover and / or for the peripheral edge seal material that encloses the evacuated gap.

[0185] It is generally understood that the solder material used for the peripheral edge seal of the VIG unit may or may not comprise one or more single layer or multi-layer primer layers. A first edge seal material of the edge seal may be arranged between a primer layer of the edge seal and the first and / or second glass sheet. The first edge seal material may e.g. be a solder glass edge seal material as described above, e.g. comprising

[0186] • one or more of AI2O3, SiC>2, MgO, P2O5, Bi2Os, ZnO, Nb20s, Ag2O, and / or MnO, such as a solder comprising Bi2O3, TeC>2, and V2O5 or such as a solder comprising Ag2O, TeC>2, and V2O5 and / or

[0187] • comprise Bi20s, e.g. in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0188] The primer layer(s) of the edge seal may e.g. be a solder glass edge seal primer material as described above. In one or more embodiments of the present disclosure, one or both of the one or two primer layers of the peripheral edge seal may comprise one or more inorganic oxides, such as at least 50 wt% of one or more inorganic oxides. In one or more embodiments of the present disclosure, each of the one or two primers of the edge seal may comprise a mixture of oxides, such as oxides chosen from Li, B, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Zn, Zr, Mo, Sn, Pb, and / or Bi oxides. In one or more embodiments of the present disclosure, each of the one or two primers of the edge seal, comprises Bi, such as Bi20s. In a further embodiment, one or both of the one or two primer layers comprise at least 40 wt-%, such as at least 50 wt-% Bi20s.

[0189] It is understood that the temperatures such as glass transition temperature, Littleton temperature and / or the like mentioned above may also, may alternatively, or may not apply for the edge serai material, such as the above mentioned edge seal material, of the edge seal.

[0190] It is however understood that in other embodiments, the peripheral edge seal may comprise edge seal solder material without the use of one or more primers.

[0191] The predefined evacuation channel(s) of the cover may be channel(s) that have / has been shaped intentionally, such as by means of a template, mold or a shaping tool. The predefined evacuation channel(s) of the cover may be deeper and / or wider than paths in the surface of the solidified solder material caused by surface roughness. The predefined evacuation channel(s) of the cover may be shaped to extend along a predefined evacuation path at a predetermined location. The present disclosure moreover relates, in a second aspect, to a method of manufacturing a vacuum insulated glass (VIG) unit. The method comprises providing a vacuum insulated glass unit assembly. The provided vacuum insulated glass unit assembly comprises:

[0192] - a first glass sheet and a second glass sheet,

[0193] - a plurality of support structures distributed in a gap between a first major surface of the first glass sheet and first major surface of the second glass sheet,

[0194] - a peripheral edge seal which is configured to seal the gap,

[0195] - wherein the first glass sheet comprises a through hole, wherein the through hole extends between the first major surface and a second, oppositely directed, major surface of the first glass sheet.

[0196] The method according to the second aspect moreover comprises providing a cover comprising:

[0197] - a covering body

[0198] - a major cover surface at a solder side of the cover, and

[0199] - a solidified glass solder material, wherein the glass transition temperature of the solidified glass solder material is lower than the glass transition temperature of the covering body.

[0200] The provided cover may in some embodiments of the present disclosure comprise one or more predefined evacuation channels having a channel width, which channel width extends between opposing walls, such as elongated walls, of the solidified solder material. Each of the one or more predefined evacuation channels extends in an evacuation direction towards the outer periphery of the cover. Additionally or alternatively, in some optional embodiments of the present disclosure, the solidified glass solder material of the provided cover covers at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface.

[0201] The method according to the second aspect further comprises the steps of

[0202] - arranging the provided cover so that the solidified seal material is placed between a surface part of the first glass sheet and the covering body, and so that the covering body covers at least a part of the through hole,

[0203] - evacuating the gap of the vacuum insulated glass unit assembly by means of a pump, so that gas, such as air, in the gap is evacuated through the through hole, - heating the solidified seal material by means of a heater so as to soften the solidified seal material, thereby providing that the softened seal material adhere to the surface part of the first glass sheet around the through hole,

[0204] - cooling the softened seal material so as to harden the softened seal material, thereby sealing the evacuated gap.

[0205] The VIG unit manufacturing solution according to embodiments of the present disclosure may provide several advantages. For example, faster and / or more reliable VIG unit manufacturing may be obtained. A more simple VIG unit manufacturing solution, and / or more freedom in VIG unit manufacturing, may additionally or alternatively be obtained by a solution according to embodiments of the present disclosure.

[0206] For example, in some embodiments, advantageous evacuation of the gap of the VIG unit assembly may be obtained.

[0207] For example, in some embodiments, "vacuum clamping" of the peripheral edge seal by means of evacuating the gap of the VIG unit assembly while the edge seal material is heated and softened may be enabled in a more simple way.

[0208] The solidified seal material of the provided cover may be a structurally hard seal material that is at a temperature where it is not liquified / fluent. For example at a temperature below the glass transition temperature of the seal material. The solidified seal material of the cover that is arranged so as to cover the through hole may be the result of an initial, first heating / firing of the glass solder material so as to soften the solder material on the covering body during manufacturing of the cover, where the first heating is provided prior to arranging the cover so as to cover the through hole. Hence, the heating of the solidified seal material by means of said heater so as to soften it to provide that the softened seal material adhere to the surface part of the first glass sheet around the through hole, may be considered a second heating / firing of the seal material. Various embodiments hereof are described in more details further below.

[0209] In one or more embodiments, the vacuum insulated glass (VIG) unit assembly with the cover may be heated in a furnace, such as prior to said softening of the solidified seal material of the cover. The cover comprising the solidified seal material may easily be placed before the VIG unit assembly is heated in the furnace and before the gap of the VIG unit assembly is evacuated.

[0210] In one or more embodiments of the second aspect, said provided cover is a cover according to any of the previously described embodiments.

[0211] In one or more embodiments of the second aspect, one or more gas passages in the solidified glass solder material of the cover is / are provided / obtained as a consequence of a surface roughness of said surface part of the first glass sheet. In some further embodiments hereof, the surface roughness of the solidified seal material surface is provided by means of protrusions at / in the surface of the seal material of the cover wherein said protrusions are arranged staggered and / or substantially randomly, across the surface of the glass solder material.

[0212] This may provide a simple and / or efficient gas evacuation when the cover is used during VIG unit manufacturing. It may also help to provide a simple and / or efficient gap sealing solution. It may additionally help to enable a space saving solution and / or a more cost efficient solution.

[0213] In one or more embodiments of the second aspect, the surface roughness of the surface of the solidified seal material which faces said surface part of the first glass sheet is above 10 pm, such as above 25 pm, such as above 35 pm. In some embodiments hereof, said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0214] In one or more embodiments of the second aspect, said surface roughness of the surface of the solidified solder material is obtained as a result of a pre-heating of the solder material of the cover, and a subsequent pre-cooling of the softened solder material so as to solidify the solder material. In some embodiments hereof, the surface roughness at least partly is caused by outgassing of the glass solder material during manufacturing of the cover.

[0215] In one or more embodiments of the second aspect, the surface roughness of the solidified solder material surface of the cover is the surface roughness over at least 90%, such as at least 95%, such as at least 98% of the surface area of the solidified solder material surface which is unbonded to the surface of the covering body.

[0216] In one or more embodiments of the second aspect, the method comprises providing said through hole, such as the full through hole, in the first glass sheet, wherein said providing of the through hole comprises laser cutting at least a part of the through hole in the first glass sheet, wherein said laser cutting is conducted prior to or during assembling of the vacuum insulated glass (VIG) unit assembly.

[0217] Laser cutting of the through hole may e.g. provide a solution that may be easy to control and / or adapt. The laser cutting of the through hole may also enable a cost efficient and / or fast solution. The laser cutting may additionally enable provide a certain, such as predefined, surface roughness at the glass sheet surface which may help to improve or provide one or more gas passages between the seal material of the cover and the glass sheet.

[0218] In one or more embodiments of the second aspect, the first glass sheet is a tempered glass sheet, such as a thermally tempered glass sheet, such as wherein said laser cutting is provided prior to tempering of the first glass sheet.

[0219] In one or more embodiments of the second aspect, a clamping force is provided by means of a clamping part so as to force the covering body towards said surface part of the first glass sheet, such as during and / or after said heating of the solidified solder material so as to soften the solidified solder material.

[0220] The clamping force may e.g. provide an improved manufacturing of a VIG unit. For example, it may help to provide a consistent yield of VIG units and / or an improved seal of the evacuated gap.

[0221] In one or more embodiments of the second aspect, said clamping force is configured to keep the cover at a desired cover space over the through hole , such as during said evacuation of the gap and / or during moving of the Vacuum Insulated Glass unit assembly. This may provide an improved manufacturing of a VIG unit. For example, it may help to provide a consistent yield of VIG units and / or a more simple VIG unit manufacturing.

[0222] In one or more embodiments of the second aspect, the clamping force directly or indirectly pushes the covering body, for example so as to deform the softened seal material. This may provide an improved seal of the evacuated gap and / or help to provide a less space consuming cover.

[0223] In one or more embodiments of the second aspect, the clamping force pushes the covering body so as to provide that a part of the softened seal material moves in between a side surface of the covering body and a side surface of the first glass sheet which faces the side surface of the covering body.

[0224] This may e.g. enable improved control of the position of the covering body surface that faces away from the gap. Additionally or alternatively, it may provide improved strength as the seal material hereby may adhere to a larger surface area.

[0225] In other embodiments, the solder material may be maintained at a location where it does not move in between a side surface of the covering body and a side surface of the first glass sheet which faces the side surface of the covering body.

[0226] In one or more embodiments of the second aspect, the clamping part comprises a spring configured to provide said clamping force.

[0227] The spring may be advantageous as it may be reused and / or provide a consistent, desired force onto the cover. In some embodiments, an evacuation cup for evacuating the gap through the through hole may comprise the spring, such as a spring attached to the evacuation cup. The spring may in some embodiments be arranged in the evacuation cup's interior cavity.

[0228] In one or more embodiments of the second aspect, the method comprises arranging an evacuation cup, such as on the second surface of the first glass sheet, so as to cover the through hole, wherein said evacuation of the gap comprises evacuating the gap by means of a pump which is in fluid communication with an interior cavity of the evacuation cup. This may e.g. help to provide a reliable gap evacuation. It may also enable providing a space saving, simple and / or cost efficient VIG unit manufacturing. A plurality of VIG unit assemblies with covers may be arranged in the same furnace and be individually evacuated by means of different cups connected to a pump, such as a common pump.

[0229] In one or more embodiments of the present disclosure, the clamping part is arranged inside the evacuation cup, such as is attached to a housing of the evacuation cup. This may e.g. provide manufacturing advantages and / or reduce the amount of process steps.

[0230] In one or more embodiments of the second aspect, the heating of the solidified solder material of the cover so as to soften the solidified solder material to provide that the solder material adhere / bonds to the surface part of the first glass sheet around the through hole comprises heating by radiation heating provided by means of a radiation heater which emits a heating beam. This may e.g. be advantageous from a manufacturing point of view.

[0231] In one or more embodiments of the second aspect, the radiation heater comprises a laser, and wherein said heating beam is a laser beam. Laser heating may enable an advantageous local heating of the seal material of the cover. It may also enable a fast heating and / or a more controlled heating of the seal material, e.g. based on a predefined heating profile.

[0232] In one or more embodiments of the second aspect, the second glass sheet is placed between the radiation heater and the seal material of the cover so that the seal material of the cover is heated by means of a heating beam which is radiated through the second glass sheet.

[0233] This may e.g. enable a more simple manufacturing and / or provide more freedom in selecting solutions for the manufacturing of the VIG unit when sealing the gap. For example, it enables using a spring that may be placed directly above the covering body, it may enable using a cover of a material that may absorb the energy from the heating beam, it may enable a more space saving solution and / or the like. In one or more embodiments of the present disclosure, said heating of the solidified solder material of the cover so as to soften the solidified solder material comprises heating to a temperature above the glass transition temperature and to a temperature so as to soften the solder material in order to obtain a bonding between the solder material and the first glass sheet.

[0234] In one or more embodiments of the second aspect, the through hole is a stepped through hole comprising a smaller diameter portion and a larger diameter portion, wherein the larger diameter portion is arranged proximate the second surface of the first glass sheet and wherein the smaller diameter portion is arranged proximate the gap, wherein a step surface extends between the larger diameter portion and the smaller diameter portion, wherein said arranging of the cover comprises arranging the solidified solder material opposite to, such as so as to support on, the step surface so that the covering body is arranged in the larger diameter portion and covers the smaller diameter portion.

[0235] The stepped through hole may be a countersunk hole.

[0236] A stepped through hole may provide several advantages. For example, it may provide a more space saving solution. It may also enable obtaining a more mechanically resistant solution. The stepped through hole may also enable a more aesthetically pleasing solution.

[0237] The larger diameter portion and the smaller diameter portion may in embodiments of the precent disclosure be circular holes. The larger diameter portion and the smaller diameter portion may in embodiments of the precent disclosure be substantially concentric holes.

[0238] The step surface (also called the floor surface in the present document) may be shaped so as to extend in a direction that is substantially parallel with / to a plane defined by a major surface of the first glass sheet, or it may be shaped to incline with an angle, such as an acute angle, relative to this pane. In one or more embodiments of the present disclosure, the diameter of the larger diameter portion is at least 2 mm, such as at least 3 mm, larger than the diameter of the smaller diameter portion.

[0239] In one or more embodiments of the present disclosure, the diameter of the larger diameter portion is between 5 mm and 12 mm, such as between 6 mm and 9 mm.

[0240] This may e.g. provide a space saving solution and / or a more visually pleasing solution.

[0241] In one or more embodiments of the present disclosure, the width, such as diameter, of the covering body is smaller than the width, such as diameter, of the larger diameter portion, wherein the difference in diameter between the diameter of the covering body and the diameter of the larger diameter portion is less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

[0242] This may e.g. provide a more resistant solution. Experiments have indicated that if the covering body diameter is too small relative to the smaller diameter portion and / or if the smaller diameter portion gets too large, the covering body may be more likely to break.

[0243] In one or more embodiments of the present disclosure, the thickness of the covering body is 2.5 mm or less, such as 2.1 mm or less, such as 1.5 mm or less.

[0244] In one or more embodiments of the present disclosure, the thickness of the covering body is between 0.7 mm and 2.9 mm, such as between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm (endpoints included).

[0245] In one or more embodiments of the present disclosure, the depth of the larger diameter portion extends over less than 70%, such as over less than 60%, such as over less than 50%, of the thickness of the first glass sheet,

[0246] In one or more embodiments of the present disclosure, the depth of the larger diameter portion is between 20% and 70%, such as between 30% and 60%, such as between 40% and 50% of the thickness of the first glass sheet. In one or more embodiments of the present disclosure, the depth of the larger diameter portion is between 1 mm and 4 mm, such s between 1.5 mm and 3 mm, such as between 1.9 mm and 2.5 mm, such as between 1.9 mm and 1.2 mm,

[0247] In one or more embodiments of the present disclosure, the depth of the larger diameter portion is between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm, such as between 1.6 mm and 2 mm.

[0248] This may e.g. provide a robust VIG unit and / or a VIG unit where the cover may be arranged within ± 1 mm, such as within ± 0.5 mm, such as flush with or below the plane defined by the major surface of the glass sheet in which the through hole is provided.

[0249] In one or more embodiments of the present disclosure, the maximum thickness of the seal material between the covering body and said surface part of the first glass sheet, after said sealing of the gap, is between 0.050 mm and 0.4 mm, such as between 0.075 mm and 0.3 mm, such as between 0.125 mm and 0.250 mm.

[0250] In one or more embodiments of the present disclosure, the maximum thickness of the seal material, such as said solder material, between the covering body and said surface part of the first glass sheet, after said sealing of the gap (6), is less than 0.4 mm, such as less than 0.3 mm, such as less than 0.250 mm.

[0251] This may e.g. provide a more space-saving solution and / or a solution that is resistant / strong.

[0252] In one or more embodiments of the present disclosure, the first glass sheet and / or the second glass sheet, such as tempered, such as thermally tempered, glass sheets, has a thickness (TH1) between 2 mm and 5 mm, such as between 3 mm and 4 mm, such as between 3.7 mm and 4 mm (both endpoints included).

[0253] This may e.g. provide a VIG unit that is strong but still has a low weight when compared to the heat insulation performance. Additionally, it may provide a VIG unit with a reduced CO2 foot print and / or a cost efficient VIG unit. In one or more embodiments of the present disclosure, the thickness of the covering body is at least 30% lower, such as at least 50% lower, or at least 60% lower, than the thickness of the first glass sheet.

[0254] In one or more embodiments of the present disclosure, the thickness of the covering body is at least 30% lower, such as at least 50% lower, or at least 60% lower, than the thickness of the first glass sheet.

[0255] In one or more embodiments of the present disclosure, the thickness of the covering body is between 30% and 85% lower, such as between 40% and 60% lower, such as between 45% and 55% lower, than the thickness of the first glass sheet.

[0256] In one or more embodiments of the present disclosure, the thickness of the covering body is between 30% and 55% lower, such as between 36% and 46% lower, such as between 39% and 44% lower, than the thickness of the first glass sheet.

[0257] In one or more embodiments of the present disclosure, the thickness of the covering body is lower than the depth of the larger diameter portion.

[0258] In one or more embodiments of the present disclosure, the thickness of the covering body is at least 5% lower or at least 10% lower, than the depth (DE1) of the larger diameter portion.

[0259] In one or more embodiments of the present disclosure, the thickness of the covering body is at least 0.05, such as at least 0.1, such as at least 0.15 mm lower than the depth of the larger diameter portion.

[0260] In one or more embodiments of the present disclosure, the thickness of the covering body is between 0.05 - 0.5 mm, such as between 0.15 - 0.4 mm, such as at between 0.18 - 0.25 mm lower than the depth of the larger diameter portion.

[0261] In one or more embodiments of the present disclosure, the thickness of the covering body is between 3% and 30% lower, such as between 5% and 20% lower , such as between 8% and 15% lower, than the depth of the larger diameter portion. A thickness of the covering body according to various embodiments mentioned above may e.g. provide a robust VIG unit and / or a space saving solution.

[0262] In one or more embodiments of the second aspect, the method comprises laminating the vacuum insulated glass (VIG) unit, wherein said lamination of the vacuum insulated glass (VIG) unit comprises attaching a lamination glass sheet to the second major surface of the first glass sheet by means of a lamination interlayer, optionally so that the lamination glass sheet extends over and covers the cover and the through hole. In some further embodiments hereof, the lamination interlayer adheres to the covering body.

[0263] A laminated VIG unit may provide a more safe VIG unit. For example if the VIG unit is used in a roof window. A laminated VIG unit may also provide a more mechanically resistant solution. IT may also provide mechanical protection of the cover and the sealed through hole.

[0264] In one or more embodiments of the present disclosure, the covering body, after said cooling the softened seal material so as to harden the softened seal material to seal the evacuated gap, extends through a plane comprising the major surface of the first glass sheet that faces the lamination glass sheet.

[0265] In one or more embodiments of the present disclosure, the covering body may extend into the lamination interlayer. This may provide that the covering body extends into the lamination interlayer, but not into the lamination glass sheet. This may e.g. be advantageous in relation to manufacturing of the VIG unit.

[0266] In one or more embodiments of the third aspect, the lamination interlayer has a thickness of at least 0.4 mm, such as at least 0.6 mm, such as at least 0.7 mm

[0267] The lamination interlayer may in some embodiments have an average thickness between 0.4 mm and 2 mm, such as between 0.5 mm and 1.2 mm, such as between 0.7 mm and 1 mm.

[0268] In one or more embodiments of the third aspect, the surface of the covering body which faces away from the seal material is at a level below the second surface of the first glass sheet after said cooling of the softened seal material so as to seal the evacuated gap, and wherein the lamination interlayer extends into the through hole, such as into a larger diameter portion of the through hole.

[0269] In one or more embodiments of the present disclosure, the first glass sheet and / or the second glass sheet is a tempered glass sheet such as a thermally tempered glass sheet.

[0270] Tempered glass sheets, such as chemically tempered glass sheet or thermally tempered glass sheet enables providing a strong VIG unit. For example, the glass mass of the VIG unit may be reduced while still obtaining a strong VIG unit when using hardened glass sheets. Additionally or alternatively, the distance between the support structures, such as pillars, in the gap may be increased, thus providing a more visually appealing VIG unit. Each support structure may also act as a small cold bridge, and by increasing the mutual distance between the support structures, the amount of support structures in the gap may be decreased, leading to a VIG unit with better insulation performance such as thermal insulation performance.

[0271] If the VIG unit is for use as a building window or a refrigerator door / lid, the VIG unit may be subjected to temperature differences causing that the first and second glass sheets have different temperatures. Due to the edge seal being e.g. a solder glass edge seal, the VIG unit has a stiff edge seal. This may cause edge deflection, such as an edge deflection curve between corners of the VIG unit, or at least cause stress in the VIG unit. It may be advantageous to e.g. use thermally tempered glass sheets in order to provide a VIG unit which is cost efficient, less heavy, has a good thermal insulation performance and which is still able to cope stress in the edge seal and glass caused by different glass sheet temperatures, for example where thr temperature difference between the glass sheets is at least 30 °C, such as at least 40 °C, such as at least 50°C.

[0272] In one or more embodiments of the present disclosure, the covering body comprises or consist of a glass body such as a structural glass body, such as an annealed glass body. A glass body may provide desired advantages, such as temperature resistance and / or improved matching of coefficient of thermal expansion CTE with the CTE of the seal material of the cover comprises glass solder material. In one or more embodiments of the present disclosure, at the final vacuum insulated glass unit, the surface of the covering body which faces away from the gap is configured to be arranged less than 1 mm, such as less than 0.6 mm, for example less than 0.4 mm, from a plane defined by the second major surface of the first glass sheet.

[0273] In one or more embodiments of the present disclosure, the surface of the covering body which faces away from the gap and the sealing material is arranged substantially flush with or below the second major surface of the first glass sheet.

[0274] The evacuation of the gap should be understood as proceeding through a collective system of channels I passages comprising the smaller diameter portion of the through hole, channels and / or passages, such as defined between the covering body and e.g. a floor of a larger diameter portion of the through hole, such as between solidified solder material and the floor, and the space between the side surface of the covering body and the side surface of the larger diameter portion. Therefore, an improved evacuation may be obtained by balancing these various sections of the air flow so as to achieve a suitable air resistance. For example, a large smaller diameter portion of the through hole may be unnecessary if the distance between the covering body side surface and the side surface of the larger diameter portion of the through hole is too small. Then the small inter-side surface distance will dictate a large air resistance, which will be the limiting factor / bottleneck in determining the evacuation rate.

[0275] In one or more embodiments of the second aspect, the average flow resistance from the gap to the ambient environment, such as to the interior of an evacuation cup, when determined in seconds per liter (s / L) evacuated gas, is less than 30 s / L, such as less than 20 s / L, such as less than 18 s / L.

[0276] This may provide an efficient flow for evacuating a gap of larger VIG units

[0277] In one or more embodiments of the second aspect, the average flow resistance determined in seconds per liter (s / L) in the area of the through hole, such as a lower diameter portion of the through hole, is less than 15 (s / L), such as less than 10 s / L, such as less than 8 s / L

[0278] This may provide an efficient flow for evacuating a gap of larger VIG units In one or more embodiments of the second aspect, the average flow resistance in the area from the through hole, such as an outlet (during gap evacuation) of a lower diameter portion, and past the solidified solder material, determined in seconds per liter, is less than 10 (s / L), such as less than 8 s / L, such as less than 4 s / L.

[0279] This may provide an efficient flow for evacuating a gap of larger VIG units. Tests have showed that optimized solder material layout of the solidified solder material with evacuation channels and / or evacuation paths may help to provide a more efficient and optimized gap evacuation.

[0280] In one or more embodiments of the second aspect, the average flow resistance in an area from the solidified solder material and in between the side surface of the covering body and a side surface part of the first glass sheet enclosing a larger diameter portion of the through hole, determined in seconds per liter (s / L), is less than 15 (s / L), such as less than 9 s / L, such as less than 7 s / L.

[0281] This may provide an efficient flow for evacuating a gap of larger VIG units.

[0282] In one or more embodiments of the present disclosure, the first glass sheet comprises a plurality of discrete support standoffs spaced, for example circumferentially, around the through-hole, wherein the spacing between the support standoffs forms gas-flow passages extending between the standoffs, the surface of the solidified glass solder material, and the surface of the first glass sheet extending between adjacent standoffs.

[0283] This may e.g. help to provide an improved evacuation of gas from the gap. Additionally or alternatively, it may allow more freedom / difference in the shape of solidified seal different covers used for different VIG units, and hence provide an advantage in order to obtain an efficient evacuation, faster manufacturing and / or improved yield of VIG units when manufacturing larger quantities of VIG units.

[0284] In one or more embodiments of the present disclosure, a floor surface of the larger- diameter portion comprises the plurality of discrete support standoffs.

[0285] In one or more embodiments of the present disclosure, the plurality of discrete support standoffs are integral with the first glass sheet, for example by being shaped into the first glass sheet by means of laser cutting, such as during providing the through hole.

[0286] This may e.g. ease VIG unit manufacturing and / or provide a solution enabling a string bond between the first glass sheet and the seal material of the cover. In one or more embodiments of the present disclosure, each of the plurality of discrete support standoffs is oblong, such as wherein the length direction of the standoff extends in a direction radial to the through-hole.

[0287] This may assure good support of the cover and / or help to obtain a more over-all smoothness of the surface that the solder material of the cover is intended to bond with.

[0288] In other embodiments, the standoffs may comprise a plurality of intended, designed protrusions in the surface, such as a step surface, for example comprising a convex, such as semi-spherical or box shaped protrusions arranged in a grid in line or staggered in a radial direction from a smaller diameter portion to a wall enclosing a larger diameter portion of the through hole.

[0289] In one or more embodiments of the present disclosure, at least one of the plurality of discrete support standoffs terminates at a predetermined distance from an edge of the through-hole.

[0290] This may help to ensure a strong bonding between the solder material and the glass sheet around the through hole, such as smaller diameter portion.

[0291] In one or more embodiments of the present disclosure, one or more predefined gasflow passages, such as one or more channels, arranged said between standoffs is / are arranged, such as shaped, in the surface of the first glass sheet that faces the surface of the solidified glass solder material, which one or more predefined evacuation channels provides a fluid communication in between the solidified glass solder material and the first glass sheet during evacuation of the gap.

[0292] In one or more embodiments of the present disclosure, the one or more standoffs each has a height of at least 0.05 mm, such as at least 0,08 mm, such as at least 0.1 mm.

[0293] This may assist in obtaining a reduced flow resistance and / or an improved evacuation process.

[0294] In one or more embodiments of the present disclosure, the one or more standoffs each has a height of less than 0.5 mm, such as less than 0.2 mm.

[0295] This may e.g. help to obtain a space saving solution and / or enable improved bonding between solder material and glass surface. In one or more embodiments of the present disclosure, the one or more standoffs each has a height between 0.05-0.5 mm, such as between 0.05 - 0.2 mm (endpoints included).

[0296] In one or more embodiments of the present disclosure, the one or more standoffs each has a width of at least 0.2 mm, such as at least 0.3 mm, such as at least 0.4 mm

[0297] In one or more embodiments of the present disclosure, the one or more standoffs each has a width of less than 1.5 mm, such as less than 0.11 mm, such as less than 0.7 mm.

[0298] In one or more embodiments of the present disclosure, the one or more standoffs each has a width (B97) between 0.2-1.5 mm, such as between 0.3 - 0.11 mm, such as between 0.4-0.7 mm (endpoints included).

[0299] The various embodiments of standoff dimensions mentioned above may e.g. provide an advantageous tradeoff between enabling improved gap evacuation and good bonding between the first glass sheet and the solder material of the cover during sealing of the through hole to seal the evacuated gap.

[0300] In one or more embodiments of the present disclosure, the diameter of the through hole, such as a smaller diameter portion of the through hole, is between 1.5 mm and 3.5 mm, such as between 1.7 mm and 2.4 mm , such as between 1.8 mm and 2.2 mm, In one or more embodiments of the present disclosure, the diameter of the through hole, such as a smaller diameter portion of the through hole, is between 1.9 mm and 3.8 mm, such as between 2.5 mm and 3.5 mm , such as between 2.8 mm and 3.2 mm. This may provide an advantageous trade-off between reducing the through hole foot print and enabling efficient, such as fast and / or thorough gap evacuation.

[0301] In one or more embodiments of the second aspect, the method comprises the step of placing and storing each of the one or more covers in a controlled, such as reduced, such as sealed, atmosphere environment in a container until they are to be used, such as used for sealing the gap of a VIG unit.

[0302] This may e.g. provide that pollution that may affect the sealing quality when sealing the evacuated gap may be reduced or prevented.

[0303] The covers may also be removed from the container and placed at the VIG unit assembly in a cleaner environment to reduce pollution. In one or more embodiments of the present disclosure, the controlled atmosphere is controlled by means of a desiccator and / or a getter.

[0304] In one or more embodiments of the present disclosure, the controlled atmosphere environment is a reduced atmosphere having a pressure of no more than 0.5 atm, such as no more than 0.2 atm, such as no more than 0.1 atm.

[0305] In one or more embodiments of the present disclosure, the method comprises the step of placing each of the one or more covers in a controlled atmosphere environment, such as a reduced atmosphere environment in a container, until they are to be used, such as used for sealing the gap of a VIG unit.

[0306] This may for example reduce contamination from the ambient surroundings of the surfaces of the covers before they are to be used for sealing the gap. For instance, it may reduce the presence of adsorbed gasses, such as moisture, and / or residues from organic matter that may otherwise cover the surfaces of the cover if it was subjected to ambient air during a prolonged period before being used in the final manufacture of a VIG unit. This may help to obtain a VIG unit of improved quality since contamination of the VIG unit, such as during sealing of the evacuated gap may be reduced.

[0307] Alternatively, the cover(s) may be arranged in an atmosphere comprising or containing a gas that reduces contamination of the cover.

[0308] In one or more embodiments of the present disclosure, the controlled, such as reduced atmosphere environment is controlled by means of a desiccator and / or a getter.

[0309] The desiccator and / or getter for storing the covers may comprise an active medium that may adsorb any gasses that leak into and / or outgas from the contents of the desiccator. Additionally or alternatively, the container for storing the covers may comprise a pump to remove air during the storage period.

[0310] In one or more embodiments of the present disclosure, the reduced atmosphere environment in the container has a pressure of no more than 0.5 atm, such as no more than 0.2 atm, such as no more than 0.1 atm. In one or more embodiments of the second aspect, the step of heating the solidified solder material comprises raster scanning a laser beam across the surface of the solidified solder material that faces away from the covering body.

[0311] In order to homogeneously heat the solder material to seal the gap, the inventors have found that a laser may favorably be scanned in a raster pattern across the surface to heat and soften the solidified solder material when the evacuated gap is to be sealed. Rather than following the circular shape of the covering body, a linear raster pattern is sufficient and / or favorable for obtaining an efficient heating of the seal material. The heating may be understood as being provided by a laser beam shone either from the top of the covering body or from the bottom. In the first instance, the laser beam passes through the covering body glass sheet and hits the surface of the seal material that abuts the glass of the covering body. In the latter case, the laser beam passes through the second glass sheet of the VIG unit and hits a primer or a solidified solder material of the cover that is opposite, such as proximate, the glass sheet of the covering body.

[0312] In one or more embodiments of the present disclosure, said raster scanning comprises scanning the laser beam in a pattern comprising straight lines separated by a distance in the range of 0.5 - 3 mm, such as in the range of 1 - 2.5 mm, such as in the range of 1.4 - 2.0 mm.

[0313] By scanning the laser in parallel lines that are closely separated, the seal material is heated substantially homogeneously. The laser scanning speed may be selected so as to cover the entire surface of the covering body many times during the heating step. For example, the laser scanning speed may be at least 1 cm / s, such as at least 5 cm / s, such as at least 10 cm / s. A high laser scanning speed may aid in providing a homogeneous heating of the seal material.

[0314] As an alternative pattern to the straight-line raster pattern, the laser may be scanned in a circular manner. For instance, the laser may be scanned in a circle with a diameter similar to a diameter of the seal material. In one or more embodiments that circular scanning is modified by a wobble effect such that the laser beam is periodically moved out of the circular path. This may provide a more homogeneous heating of the entire surface area of the seal material. Additionally or alternatively, the laser may be scanned in a series of concentric circles so as to cover the entire surface area of the seal material. In a different embodiment, the laser may be scanned in a spiral pattern.

[0315] In one or more embodiments of the present disclosure, said raster scanning proceeds for a period in the range of 1 - 6 minutes, such as in the range of 2 - 4 minutes, such as 3 minutes.

[0316] The heating step may be short enough so as to avoid prolonging the manufacturing process. On the other hand, the heating step should be long enough that the heating of the seal material is sufficient without being too quick, as this could induce stresses and / or inhomogeneities in the seal material and / or covering body. Also, the heating step must be long enough to allow the softened seal material to flow into so as to close any evacuation channels in the seal material.

[0317] In one or more embodiments of the present disclosure, the width of the laser beam is larger, such as at least 2 times larger, such as at least 3 times larger, than the distance between the straight lines of the raster pattern.

[0318] By selecting a laser beam width that is larger than the distance between lines in the raster pattern, the heating of the seal material is ensured to be more homogeneous. This is because the shoulders of the laser beam will heat even the areas between the lines efficiently, as the center of the beam passes along the lines. Additionally, a large beam width may help to provide that that each area is irradiated with a substantial laser power multiple times during the time it takes to scan each pattern. This may for example provide a better, such as a more homogeneous, heating.

[0319] The present disclosure moreover, in a third aspect, relates to a vacuum insulated glass unit comprising:

[0320] - a first glass sheet and a second glass sheet,

[0321] - a plurality of support structures distributed in an evacuated gap between a first major surface of the first glass sheet and first major surface of the second glass sheet,

[0322] - a peripheral edge seal which is configured to seal the evacuated gap, - wherein the first glass sheet comprises a through hole, wherein the through hole extends between the first major surface and a second, oppositely directed, major surface of the first glass sheet,

[0323] - a cover comprising a covering body, wherein glass solder material is placed between a surface part of the first glass sheet and the covering body, and wherein the covering body covers the through hole, wherein said glass solder material has a the glass transition temperature that is lower than the glass transition temperature of the covering body, preferably wherein the solidified glass solder material of the cover covers at least 40%, such as at least 60%, such as at least 70% of the area of a major cover surface of the cover.

[0324] Experiments have shown that this may provide a mechanically strong VIG unit which is resistant to both stresses in the VIG unit caused by a temperature difference and resistant to outer forces such as impacts.

[0325] In one or more embodiments of the present disclosure, said vacuum insulated glass unit according to the third aspect may be obtained by means of a a method according to any of the preceding embodiments, such as one or ore embodiments according to the second aspect.

[0326] In one or more embodiments of the third aspect, wherein the through hole is a stepped through hole comprising a smaller diameter portion and a larger diameter portion, wherein the larger diameter portion is arranged proximate the second surface of the first glass sheet and wherein the smaller diameter portion is arranged proximate the evacuated gap, wherein a step surface is arranged between the larger diameter portion and the smaller diameter portion, wherein said glass solder material is placed between the step surface and the covering body so that the covering body is arranged in the larger diameter portion and covers the smaller diameter portion.

[0327] In one or more embodiments of the third aspect, the diameter of the larger diameter portion is at least 2 mm, such as at least 3 mm, larger than the diameter of the smaller diameter portion. In one or more embodiments of the present disclosure, the diameter of the larger diameter portion is between 5 mm and 12 mm, such as between 6 mm and 9 mm.

[0328] In one or more embodiments of the third aspect, the diameter of the covering body is smaller than the diameter of the larger diameter portion, wherein the difference in diameter between the diameter of the covering body and the diameter of the larger diameter portion is less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

[0329] In one or more embodiments of the third aspect, the thickness of the covering body is

[0330] 2.5 mm or less, such as 2.1 mm or less, such as 1.5 mm or less.

[0331] In one or more embodiments of the third aspect, the thickness of the covering body is between 0.7 mm and 2.9 mm, such as between 0.9 mm and 2.4 mm, such as between

[0332] 1.6 mm and 2.2 mm (endpoints included).

[0333] In one or more embodiments of the third aspect, the depth of the larger diameter portion extends over less than 70%, such as over less than 60%, such as over less than 50%, of the thickness of the first glass sheet.

[0334] In one or more embodiments of the third aspect, the depth of the larger diameter portion is between 20% and 70%, such as between 30% and 60%, such as between 40% and 50% of the thickness of the first glass sheet.

[0335] In one or more embodiments of the third aspect, the depth of the larger diameter portion is between 1 mm and 4 mm, such as between 1.5 mm and 3 mm, such as between 1.9 mm and 2.5 mm, such as between 1.9 mm and 1.2 mm. In other embodiments, the depth of the larger diameter portion may be between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm, such as between 1.6 mm and 2 mm.

[0336] In one or more embodiments of the third aspect, the maximum thickness of the glass solder material between the covering body and said surface part of the first glass sheet is between 0.050 mm and 0.4 mm, such as between 0.075 mm and 0.3 mm, such as between 0.125 mm and 0.250 mm. In one or more embodiments of the third aspect, the maximum thickness of the glass solder material between the covering body and said surface part of the first glass sheet (2) is less than 0.4 mm, such as less than 0.3 mm, such as less than 0.250 mm.

[0337] In one or more embodiments of the third aspect, the first glass sheet and / or the second glass sheet has / have a thickness (TH1) between 2 mm and 5 mm, such as between 3 mm and 4 mm, such as between 3.7 mm and 4 mm (both endpoints included).

[0338] In one or more embodiments of the third aspect, the thickness of the covering body is at least 30% lower, such as at least 50% lower, such as at least 55% lower or at least 60% lower, than the thickness of the first glass sheet.

[0339] In one or more embodiments of the third aspect, the thickness of the covering body is between 30% and 85% lower, such as between 40% and 60% lower, such as between 45% and 55% lower, than the thickness of the first glass sheet.

[0340] In one or more embodiments of the third aspect, the thickness of the covering body is between 30% and 55% lower, such as between 36% and 46% lower, such as between 39% and 44% lower, than the thickness of the first glass sheet.

[0341] In one or more embodiments of the third aspect, the thickness of the covering body is lower than the depth of the larger diameter portion. This may provide a space saving solution and / or a VIG unit that is also resistant to impacts. It may also enable providing an aesthetically pleasing solution.

[0342] In one or more embodiments of the third aspect, the thickness of the covering body is at least 5% lower or at least 10% lower, than the depth of the larger diameter portion.

[0343] In one or more embodiments of the third aspect, the thickness of the covering body is at least 0.05, such as at least 0.1 , such as at least 0.15 mm lower than the depth of the larger diameter portion.

[0344] In one or more embodiments of the third aspect, the thickness of the covering body is between 0.05 - 0.5 mm, such as between 0.15 - 0.4 mm, such as at between 0.18 - 0.25 mm lower than the depth of the larger diameter portion. In one or more embodiments of the third aspect, the thickness of the covering body is between 3% and 30% lower, such as between 5% and 20% lower , such as between 8% and 15% lower, than the depth of the larger diameter portion.

[0345] In one or more embodiments of the third aspect, the vacuum insulated glass unit is a laminated vacuum insulated glass (VIG) unit, for example wherein the lamination glass sheet extends over and covers the cover and the through hole and / or wherein the lamination interlayer adheres to the covering body.

[0346] In one or more embodiments of the third aspect, the covering body, after said cooling the softened seal material so as to harden the softened seal material to seal the evacuated gap, extends through a plane comprising the major surface of the first glass sheet that faces the lamination glass sheet, such as wherein the covering body extend into the lamination interlayer.

[0347] In one or more embodiments of the third aspect, the first glass sheet and / or the second glass sheet is a tempered glass sheet such as a thermally tempered glass sheet.

[0348] In one or more embodiments of the third aspect, the covering body comprises or consist of a glass body such as a structural glass body, such as an annealed glass body.

[0349] In one or more embodiments of the third aspect, the surface of the covering body which faces away from the gap is configured to be arranged less than 1 mm, such as less than 0.6 mm, for example less than 0.4 mm, from a plane defined by the second major surface of the first glass sheet. This may e.g. provide a space saving and / or aesthetically appealing solution. It may also reduce the risk of unintended engagement with the cover and / or enable advantageous lamination of the VIG unit.

[0350] In some embodiments, the surface of the covering body which faces away from the gap and the sealing material is arranged substantially flush with or below the second major surface of the first glass sheet. This may e.g. provide an even more space saving and / or aesthetically appealing solution. It may also further reduce the risk of unintended engagement with the cover. In one or more embodiments of the third aspect, the first glass sheet and the second glass sheet are tempered glass sheets such as a thermally tempered glass sheets, wherein the covering body (21) comprises a glass body, wherein the through hole is a stepped through hole comprising a smaller diameter portion and a larger diameter portion, wherein the larger diameter portion is arranged proximate the second surface of the first glass sheet and wherein the smaller diameter portion is arranged proximate the evacuated gap, wherein a step surface is arranged between the larger diameter portion and the smaller diameter portion, wherein said glass solder material is placed between the step surface and the covering body so that the covering body is arranged in the larger diameter portion and covers the smaller diameter portion, optionally wherein the depth of the larger diameter portion extends over less than 60% of the thickness of the first glass sheet, wherein the depth of the larger diameter portion is between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm.

[0351] In one or more embodiments of the third aspect, the maximum thickness of the glass solder material between the covering body and said surface part of the first glass sheet is less than 0.4 mm, such as less than 0.3 mm, wherein the thickness of the covering body is at least 30% lower, such as at least 50% lower than the thickness of the first glass sheet and wherein the thickness of the covering body is lower than the depth of the larger diameter portion, optionally wherein the difference in diameter between the diameter of the covering body and the diameter of the larger diameter portion is less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

[0352] In one or more embodiments of the third aspect, the width, such as diameter, of the through hole, such as a smaller diameter portion of the through hole, is between 1 mm and 4 mm, such as between 1.4 mm and 3 mm, such as between 1.8 mm and 2.2 mm.

[0353] In one or more embodiments of the third aspect, the first glass sheet comprises a plurality of discrete support standoffs spaced, for example circumferentially, around the through-hole, wherein the spacing between the support standoffs forms gas-flow passages extending between the standoffs, the surface of the solidified glass solder material, and the surface of the first glass sheet extending between adjacent standoffs. In one or more embodiments of the third aspect, a floor surface of the larger-diameter portion comprises the plurality of discrete support standoffs.

[0354] In one or more embodiments of the third aspect, the plurality of discrete support standoffs are integral with the first glass sheet, for example by being shaped into the first glass sheet by means of laser cutting.

[0355] In one or more embodiments of the third aspect, each of the plurality of discrete support standoffs is oblong, such as wherein the length direction of the standoff extends in a direction radial to the through-hole.

[0356] In one or more embodiments of the third aspect, at least one, and preferably all, of the plurality of discrete support standoffs terminates at a predetermined distance from an edge of the through-hole.

[0357] In one or more embodiments of the third aspect, one or more predefined gas-flow passages, such as one or more channels, arranged between the standoffs is / are arranged, such as shaped, in the surface of the first glass sheet that faces the surface of the solidified glass solder material, which one or more predefined evacuation channels provides a fluid communication between the solidified glass solder material and the first glass sheet during evacuation of the gap.

[0358] In one or more embodiments of the third aspect, the one or more standoffs each has a height of at least 0.05 mm, such as at least 0,08 mm, such as at least 0.1 mm.

[0359] In one or more embodiments of the third aspect, the one or more standoffs each has a height (H97) of less than 0.5 mm, such as less than 0.2 mm.

[0360] In one or more embodiments of the third aspect, the one or more standoffs each has a height between 0.05-0.5 mm, such as between 0.05 - 0.2 mm.

[0361] In one or more embodiments of the third aspect, the one or more standoffs each has a width of at least 0.2 mm, such as at least 0.3 mm, such as at least 0.4 mm,

[0362] In one or more embodiments of the third aspect, the one or more standoffs each has a width of less than 1.5 mm, such as less than 0.11 mm, such as less than 0.7 mm. For example, in some embodiments, the one or more standoffs each has a width between 0.2-1.5 mm, such as between 0.3 - 0.11 mm, such as between 0.4-0.7 mm (endpoints included). The present disclosure moreover, in a fourth aspect, relates to a Vacuum insulated glass (VIG) unit comprising

[0363] - a first glass sheet and a second glass sheet,

[0364] - a plurality of support structures distributed in an evacuated gap between a first major surface of the first glass sheet and first major surface of the second glass sheet,

[0365] - a peripheral edge seal which is configured to seal the evacuated gap,

[0366] - wherein the first glass sheet comprises a through hole, wherein the through hole extends between the first major surface and a second, oppositely directed, major surface of the first glass sheet, a cover comprising a covering body, wherein glass solder material is placed between a surface part of the first glass sheet and the covering body, and wherein the covering body covers the through hole, wherein said glass solder material has a the glass transition temperature that is lower than the glass transition temperature of the covering body. The solidified glass solder material of the provided cover may optionally cover at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface. The first glass sheet and the second glass sheet are tempered glass sheets such as a thermally tempered glass sheets, and the covering body comprises a glass body. The through hole is a stepped through hole comprising a smaller diameter portion and a larger diameter portion. The larger diameter portion is arranged proximate the second surface of the first glass sheet and the smaller diameter portion is arranged proximate the evacuated gap. A step surface is arranged between the larger diameter portion and the smaller diameter portion. The glass solder material is placed between the step surface and the covering body so that the covering body is arranged in the larger diameter portion and covers the smaller diameter portion. The depth, such as maximum depth, of the larger diameter portion extends over less than 60% of the thickness of the first glass sheet. The depth of the larger diameter portion may be between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm. Moreover, the maximum thickness of the glass solder material between the covering body and said surface part of the first glass sheet may be less than 0.4 mm, such as less than 0.3 mm. The thickness of the covering body may be is at least 30% lower, such as at least 50% lower than the thickness of the first glass sheet and the thickness of the covering body is lower than the depth of the larger diameter portion. In some further embodiments of the fourth aspect, the difference in diameter between the diameter of the covering body and the diameter of the larger diameter portion may be less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

[0367] In one or more embodiments of the fourth aspect, the vacuum insulated glass unit is a laminated vacuum insulated glass (VIG) unit.

[0368] In one or more embodiments of the fourth aspect, said vacuum insulated glass unit is obtained by means of a method as described above, such as according to one or more embodiments of the second aspect.

[0369] In one or more embodiments of the fourth aspect, said cover is a cover according to one or more embodiments as described further above, such as one or more embodiments of the first aspect.

[0370] In one or more embodiments of the fourth aspect, wherein said vacuum insulated glass unit is a vacuum insulated glass unit according to one or more embodiments of the third aspect.

[0371] The present disclosure, in a fifth aspect, relates to a method of manufacturing one or more covers for use, such as subsequent use, during sealing of an evacuated gap of a vacuum insulated glass unit, such as a cover according to one or more embodiments described above. The method comprises:

[0372] - providing one or more covering body workpieces, wherein said one or more covering body workpieces comprises a seal material, which seal material comprises a glass solder material, wherein the seal material is arranged at a surface of the one or more covering body workpieces,

[0373] - arranging the one or more covering body workpieces in a working space,

[0374] - heating the seal material in the working space to a target temperature by means of a heater, such as wherein said heating is provided so as to provide an outgassing of the glass solder material,

[0375] - cooling the one or more heated covering body workpieces and seal material so as to solidify the seal material,

[0376] - obtaining one or more covers from the one or more cooled covering body workpieces. The heating of the seal material in the working space to the target temperature by means of the heater may in embodiments of the present disclosure provide an outgassing of the glass solder material of the seal material, also referred to as a preoutgassing in the present document.

[0377] Providing a pre-outgassing of a seal material comprising glass solder material during cover manufacturing before the cover is used at a VIG unit assembly may provide a cover that enables an improved seal of an evacuated gap of a VIG unit. The pressure in the gap of a VIG unit may be reduced to below 10A(-2) mbar, such as 10A(-3) mbar or below, and then the gap is sealed in order to provide a VIG unit with e.g. good heat insulation performance. A substantial outgassing of the seal material of the cover during the sealing of the evacuated gap may be undesired as it may possibly provide the risk of a pressure increase in the gap during gap sealing. The outgassing may be caused by e.g. burnout of binder material and / or solvent material in the seal material. Providing a pre-outgassing of the seal material of the cover may help to reduce or prevent such issues.

[0378] The heating of the seal material during cover manufacturing may additionally or alternatively help to provide a more dense seal material comprising the glass solder material. This may be the case for substantially the entire seal material mass at the respective cover, for example the entire mass of the glass solder material of the seal material.

[0379] The manufacturing of the cover(s) according to embodiments of the present disclosure may also reduce the risk of so called foaming when using the cover at a VIG unit assembly for sealing an evacuated gap.

[0380] The cover may also provide advantages in relation to placing of the cover at the VIG unit assembly, as the seal material adhere / attaches to the covering body surface.

[0381] In one or more embodiments of the fifth aspect, said heating of the seal material comprises heating to a temperature above 200°C, such as above 300°C, such as above 350°C.

[0382] The target temperature and / or heating time may be set in order to assure sufficient outgassing and / or softening of the seal material. The softening of the seal material at the working piece may comprise a softening of material in the seal material such as the glass solder material. The softening may comprise a partly or full melting of components of the seal material. The target temperature may be selected based on e.g. the seal material type and properties of the seal material. For example, the glass transition temperature and melting temperature of the seal material may differ between different seal material types, and the heating temperature may be adapted to these.

[0383] In one or more embodiments of the fifth aspect, said heating of the seal material comprises heating to a temperature between 200°C and 450°C, such as between 300°C and 400°C, such as between 320°C and 370°C.

[0384] In one or more embodiments of the fifth aspect, said working space comprises or is a vacuum chamber, and wherein the pressure is reduced in the vacuum chamber, such as by means of a pump.

[0385] In some further embodiments of the present disclosure, the pressure is reduced in the vacuum chamber at least while said glass solder material is heated in the vacuum chamber.

[0386] The inventors have found that manufacturing of a cover where the seal material is heated and softened provides an improved outgassing from the material and a more dense seal material. This may provide an improved cover that may provide an improved VIG unit gap sealing. Additionally or alternatively, it may allow for faster closure and seal of the pump out port in a VIG. The inventors have found that evacuation of the working space may help to provide an improved cover with an advantageous, solidified seal material.

[0387] In one or more embodiments of the fifth aspect, said reducing of the pressure in the vacuum chamber comprises reducing the pressure in the vacuum chamber to a pressure below 500 mbar, such as below 100 mbar, such as below 10 mbar.

[0388] In one or more embodiments of the fifth aspect, said reducing of the pressure in the vacuum chamber comprises reducing the pressure in the vacuum chamber to a pressure below 500 millibar such as below 100 millibar. In one or more embodiments of the fifth aspect, the method comprises equalizing said pressure in the vacuum chamber, such as during or after said cooling in the vacuum chamber.

[0389] If the vacuum chamber is evacuated during the cover manufacturing, the method may comprise equalizing said pressure in the vacuum chamber, such as during or after said cooling in the vacuum chamber and the covers. In certain embodiments, the equalizing of the pressure may be provided during the heating of the seal material.

[0390] In one or more embodiments of the fifth aspect, the method comprises equalizing said pressure in the vacuum chamber, such as during or after heating of the solder material.

[0391] In one or more embodiments of the fifth aspect, said heating comprises heating the glass solder material to a temperature above the rated glass transition temperature of the glass solder material.

[0392] In one or more embodiments of the present disclosure said heating of the seal material in the working space to a target temperature by means of the heater may involve convection heating and / or conduction heating. In one or more embodiments of the present disclosure, the heater may comprise a conduction heater and / or a convection heater. This may e.g. enable providing a controlled and / or efficient heating of the seal material in the working space. Additionally or alternatively, it may provide a more simple and / or cost efficient solution.

[0393] In one or more embodiments of the fifth aspect, the heater comprises a radiation heater, such as a laser.

[0394] Radiation heating may e.g. enable providing a controlled and / or adapted heating of the seal material.

[0395] In one or more embodiments of the fifth aspect, the heater heats a conduction heating part, such as a base, configured to heat the one or more covering body workpieces, so that the one or more covering body workpieces, heats the seal material.

[0396] This may provide advantageous and / or cost efficient, controlled heating of the seal material. It may also be advantageous to use conduction heating in a vacuum chamber. In some embodiments, the conduction heating part may heat the covers to the target temperature so as to provide said softening of the seal material.

[0397] In some embodiments of the present disclosure, a combined heating by means of two or more of radiation heating, convection hating and conduction heating may be provided in order to heat the seal material at the work pieces.

[0398] In one or more embodiments of the present disclosure, the temperature of the seal material may be increased, such as with a predefined heat increase rate, during the heating time until a predefined target temperature is reached.

[0399] In one or more embodiments of the fifth aspect, the temperature of the seal material is increased in the working chamber with a heat increase rate of less than 2 °C / minute, such as less than 1 °C / minute or less than 0.7 °C / minute during the heating time, such as until the target temperature is reached.

[0400] The inventors have seen indications that a slow heating of the solder material, such as from the pre-form state such as a glass solder frit material, may be advantageous in order to obtain covers with solidified solder material having advantageous properties. This may advantageously, in further embodiments, be combined with evacuation in a vacuum chamber as described according to various embodiments of the present disclosure.

[0401] In one or more embodiments of the fifth aspect, the temperature of the seal material is increased in the working chamber with a heat increase rate of between 0.1 °C / minute and 5 °C / minute, such as between 0.1 °C / minute and 2 °C / minute, such as between 0.3 °C / minute and 0.7 °C / minute, such as until the target temperature is reached.

[0402] A low heat increase rate of the seal material during the heating in the working space may accommodate extraction / release of solvent and binder from the seal material arranged at the covering body surface. It may additionally maintain a - so to say - open structure in the seal material to enable improved material outgassing during the heating of the seal material.

[0403] In one or more embodiments of the fifth aspect, said heat increase rate is provided over at least 50%, such as over at least 70% or over at least 95% of said heating time. In one or more embodiments of the fifth aspect, the heating time before the seal material reaches the target temperature is at least 3 hours, such as at least 5 hours, such as at least 8 hours.

[0404] In one or more embodiments of the fifth aspect, the amount of binder material in the solidified solder material is below 5 wt%, such as below 2 wt%, such as below 1 wt%. In one or more embodiments of the fifth aspect, the amount of solvent in the solidified solder material is below 4 wt%, such as below 2 wt%, such as below 1 wt% or below 0.2 wt%.

[0405] A low amount of binder in the solidified seal material may e.g. help to reduce outgassing during subsequent cover use when the cover is used for sealing a gap.

[0406] In one or more embodiments of the fifth aspect, said heating by means of said heater reduces the amount of binder material in the seal material, such as by at least 10 %, such as by at least 50 %, such as by at least 85 % when compared to the amount (wt%) of binder material in the seal material before said heating by means of the heater.

[0407] In one or more embodiments of the fifth aspect, the amount of binder material in the seal material after it has been heated by the heater and solidified by cooling it, is above 0.1 wt%, such as above 0.4 wt%, such as above 1 wt%,

[0408] In one or more embodiments of the fifth aspect, the amount of binder material in the solder material after it has been heated by the heater and solidified by cooling it, is between 0.1 wt% and 5 wt%, such as between 0.4 wt% and 2 wt%.

[0409] In one or more embodiments of the fifth aspect, the amount of binder material in the solder material after it has been heated by the heater and solidified by cooling it, is between 0.01 wt% and 2 wt%, such as between 0.01 wt% and 1 wt%.

[0410] In one or more embodiments of the fifth aspect, said heating by means of said heater reduces the amount of solvent material in the seal material by at least 40 %, such as by at least 80 %, such as by at least 95 % when compared to the amount of solvent material in the seal material before said heating by means of the heater. In one or more embodiments of the fifth aspect, a surface roughness of the surface of the solidified solder material which faces away from the surface of the work piece is above 10 pm, such as above 25 pm, such as above 35 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0411] In one or more embodiments of the fifth aspect, the surface roughness of the surface of the solidified solder material which faces away from the surface of the work piece is between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 75 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0412] This may e.g. enable evacuation options where the surface roughness provides that gas can be evacuated from a gap of a VIG unit assembly between a glass sheet and the surface of the seal material of the cover during VIG unit manufacturing. It may also enable improved sealing of a VIG unit gap.

[0413] Hence, prior to heating the solidified solder material of the cover to soften it in order to provide an hermetically sealed, evacuated gap of a VIG unit, the surface roughness of the seal material may help to provide gas channels between a glass surface and the seal material. These channels may be used for evacuating gas from the gap of the VIG unit assembly.

[0414] The surface roughness may be defined along a sampling length corresponding to the full length, such as defined by the circumference, of the solidified solder material at the top of the solidified seal material. This may in practice be defined along an envisaged circle which is concentric with the solidified solder material, if the solder material provides the shape of a continuous ring, and which has a diameter providing that the circle is arranged substantially midways between the outer and inner periphery of the solidified solder material. The surface roughness may e.g. be determined by means of a profilometer or a laser scanner.

[0415] The Ra surface roughness parameter may define, within the sampling length, the average roughness of the solidified solder material surface, e.g. including the deviations from the mean line. The Rz surface roughness parameter may define the difference between the highest peak and lowest valley within the sampling length. It may define the maximum height of the profile.

[0416] Surface roughness may be defined according to ISO 21920, such as ISO 21920-2.

[0417] In one or more embodiments of the fifth aspect, said providing of the one or more covering body workpieces comprises applying the glass solder material, such as a glass solder frit material, such as a glass solder material paste, to a surface of the one or more covering body workpieces.

[0418] The applied seal material may e.g. have been mixed with a solvent material so as to provide a paste-like texture of the applied solder material. This may enable providing a more controlled applying of the seal material. An outlet, such as a nozzle, may be used for applying the seal material.

[0419] In some embodiments, the seal material may e.g. be printed, such as 3D printed, onto the covering body surface. Solvent may or may not be present in the material during this process. It is generally understood that a softening temperature of the one or more covering body workpieces in some embodiments may be higher than a softening temperature of the seal material.

[0420] In some embodiments of the present disclosure, the seal material on the workpiece may be hard, such as dried out seal material. The seal material may thereafter be heated to soften the solder glass material in the working space. In other embodiments of the present disclosure, the seal material on the workpiece may be a paste like substance. The seal material may thereafter be heated first to dry out the seal material and thereafter to soften the solder glass material in the working space.

[0421] In one or more embodiments of the fifth aspect, the softening temperature of the one or more covering body workpieces is higher than a softening temperature of the solder seal material. In one or more embodiments of the fifth aspect, a softening temperature of the one or more covering body workpieces is higher than a softening temperature of the glass solder material.

[0422] One or more gas passages may in some embodiments be provided as a consequence of a surface roughness of the surface of the solidified seal material.

[0423] This may provide a simple and / or efficient gas evacuation when the cover is used during VIG unit manufacturing. It may also help to provide a simple and / or efficient gap sealing solution. It may additionally help to enable a space saving solution and / or a more cost efficient solution.

[0424] In one or more embodiments of the fifth aspect, a surface roughness of the surface of the solidified solder material which faces away from the surface of the work piece is above 10 pm, such as above 25 pm, such as above 35 pm. The surface roughness may in some embodiments be the Ra or Rz surface roughness parameter, such as the Ra parameter.

[0425] In one or more embodiments of the fifth aspect, the surface roughness of the surface of the solidified solder material which faces away from the surface of the work piece is between 10 pm , and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 80 pm. The surface roughness may in some embodiments be the Ra or Rz surface roughness parameter, such as the Ra parameter.

[0426] This may e.g. enable evacuation options where the surface roughness provides that gas can be evacuated from a gap of a VIG unit assembly between a glass sheet and the surface of the seal material of the cover during VIG unit manufacturing. It may also enable improved sealing of a VIG unit gap.

[0427] In some embodiments of the present disclosure, the surface roughness of the seal material may be larger than the surface roughness of the major glass sheet surface on which the cover may be placed.

[0428] In one or more embodiments of the fifth aspect, said surface roughness of the surface of the solidified solder material is obtained as a result of said heating of the seal material of the cover by means of the heater and the subsequent cooling of the softened seal material so as to solidify the seal material.

[0429] In one or more embodiments of the fifth aspect, said surface roughness of the seal material surface is the surface roughness over at least 90%, such as at least 95%, such as at least 98% of the surface area of the solidified solder material surface which is unbonded to the surface of the covering body.

[0430] In one or more embodiments of the fifth aspect, said solidified solder material has a height, such as a maximum height, of less than 0.6 mm, such as less than 0.4 mm, such as less than 0.3 mm.

[0431] This may e.g. provide a more space saving solution and / or a more efficient sealing solution. The local maximum height may include variations caused by surface roughness of the seal material, or said local maximum height may exclude variations caused by surface roughness of the seal material. Said extent may be the longitudinal extent of the solidified seal material.

[0432] In one or more embodiments of the fifth aspect, the surface roughness of the seal material surface is provided by means of protrusions at / in the surface of the seal material of the cover, wherein said protrusions are arranged staggered, such as substantially randomly, across the surface of the glass solder material.

[0433] In some embodiments, the staggered protrusions may provide that the one or more gas passages is / are non-straight, such as so that the protrusions may cause a deviation of the evacuated gas from a straight line during gas evacuation through the one or more gas passages.

[0434] In some embodiments, the staggered protrusions may be obtained by an initial heating of the seal material during a first firing of the seal material on the cover during cover manufacturing.

[0435] In one or more embodiments of the fifth aspect, the solidified solder material comprises or consist of a continuous ring of seal material, such as a continuous, annular ring of seal material. In one or more embodiments of the fifth aspect, the solidified solder material comprises or consist of seal material extending to follow the contour, such as shape, of a ring of seal material, such as an annular ring of seal material. In one or more embodiments of the fifth aspect, one or more predefined evacuation channels is applied in and / or separates the seal material around the ring.

[0436] This may e.g. allow for reduction of seal material amount, it may enable a more space saving solution as the seal material may be thinner, it may provide a sealing solution with larger structural integrity and / / or a uniform manufacturing result.

[0437] In one or more embodiments of the fifth aspect, the solidified solder material is in continuous, un-interrupted contact with, and continuously adheres to, the covering body surface over substantially the full extent, such as the full length, of the continuous ring of seal material.

[0438] In some embodiments of the present disclosure, the covering body may comprise or consist of a structural glass body such as an annealed glass body or an hardened glass body.

[0439] In other embodiments, the covering body may comprise or consist of a structural metal body or a structural ceramic body.

[0440] In some embodiments of the present disclosure, the thickness of the covering body (21) may be 2.5 mm or less.

[0441] In some embodiments of the present disclosure, the thickness of the covering body may be between 0.7 mm and 2.9 mm, such as between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm (endpoints included).

[0442] In one or more embodiments of the fifth aspect, said heating of the seal material comprises one or more controlled temperature holding periods between the time of initiating the heating and time of reaching the target temperature. In some embodiments the controlled temperature holding periods may be constant temperature holding periods.

[0443] Various processes take place during the heating of the seal material. For example, the seal material may comprise a binder that is added to the glass frit material. The binder e.g. help to improve manufacturability and seal quality, for example before and / or during thermal processing and / or provide a paste that is easy to apply to the surface of the covering body workpiece. This binder may be substantially removed to create a hardened solidified seal that can be reheated to provide a hermetic sealing of the pump-out port during manufacturing of the VIG unit.

[0444] In one or more embodiments of the fifth aspect, the temperature of the seal material is increased stepwise in the working chamber according to two or more heat increase rates during the heating time, such as until the target temperature is reached.

[0445] Optimization of the heat increase rate for providing an outgassed and sintered seal material may vary depending on the temperature at which the seal has been and is heated. Various temperature ranges may call for different heat increase rates. For example, it may be advantageous that the entire seal has essentially the same temperature, for example to avoid overheating parts of the seal material. Therefore, slow heat increase rates may be favorable in some embodiments. Additionally or alternatively, it may be relevant to have slow heat increase rates at various temperature intervals, where physical phenomena, such as binder burnout or glass transition, need to take place within the seal material. A slow heat increase rate and / or a controlled, such as a constant temperature, in this temperature range would provide a full transition of substantially the volume of seal material before the temperature is increased outside of the given range.

[0446] In one or more embodiments of the fifth aspect, the heat increase rate, such as heating gradient, is decreased, such as controlled to decrease as the temperature of the seal material is increased.

[0447] By decreasing the gradient and / or heat increase rate as the temperature is nearing the target temperature, one may e.g. avoid overheating any part of the seal material, which could deteriorate the inherent structural integrity of the material. Additionally or alternatively, a slow heat increase rate may provide a seal material that is in in improved equilibrium, such as temperature equilibrium at any point in time. This may e.g. aid in reducing excessive bubbling during the degassing process and / or provide a solidified solider material at the end which is suitable for sealing the through hole of a VIG unit.

[0448] In one or more embodiments of the fifth aspect, the heat increase rate is controlled so as to decrease gradually as the temperature of the seal material is increased. Such a controlled heat increase rate may provide a heating where there are no or fewer sudden changes in heat increase rate. This may provide a more homogeneous seal material.

[0449] Additionally or alternatively, in one or more embodiments of the present disclosure, the heat increase rate decreases in a stepwise manner as the temperature of the seal material is increased.

[0450] In some embodiments, the heat increase rate decreases, when compared to a previous heat increase rate, after one or more temperature holding periods such as controlled temperature holding periods.

[0451] In one or more embodiments of the fifth aspect, the heat increase rate is controlled to decrease, such as in a stepwise manner, as the temperature of the seal material is increased, such as wherein the heat increase rate decreases after one or more temperature holding periods such as constant temperature holding periods.

[0452] Such a system for controlling the heat increase rate may be simple to encode in a control unit for the furnace of the working chamber and / or may help to obtain a desired end product (solidified seal maerial). The intervals associated with each heat increase rate may correspond to physical phenomena taking place within the seal material. Additionally or alternatively, the intervals may correspond to temperatures between and / or outside the temperature ranges associated with the physical phenomena taking place within the seal material.

[0453] In one or more embodiments of the fifth aspect, said heating of the seal material, such as until the target temperature is reached, comprises heating at a controlled binder burnout temperature holding period, such as a constant binder burnout temperature holding period, at a temperature in the range of 200 - 320 °C, such as in the range of 230 - 290 °C, such as in the range of 250 - 270 °C.

[0454] In order to achieve a dense seal material, it may be relevant to remove the majority, such as substantially all, of the binder material. This may for example proceed at a binder burnout temperature range. The heating of the seal material may provide a predefined holding period at said temperature range in order to ensure sufficient binder burnout. It may be desirable to maintain a controlled, such as a constant, temperature within the range in order to avoid undesired effects of the binder burning off too quickly. For example, such overheating could result in bubbles and / or gaseous inclusions in the seal material, which may cause a suboptimal seal quality.

[0455] In one or more embodiments of the fifth aspect, the controlled, such as constant, binder burnout temperature holding period has a duration of at least 15 minutes, such as at least 30 minutes, such as at least 60 minutes.

[0456] In one or more embodiments of the fifth aspect, the controlled binder burnout temperature holding period, such as constant binder burnout temperature holding period, has a duration in the range of 15 minutes - 2 hours, such as in the range of 30 minutes - 1.5 hours.

[0457] In one or more embodiments of the fifth aspect, the binder burnout temperature holding period, such as constant binder burnout temperature holding period, has a duration of less than 3 hours, such as less than 2 hours, such as less than 1.5 hours.

[0458] In order to ensure sufficient binder burnout, it may be favorable to provide a long binder burnout temperature holding period. Meanwhile, in order to optimize the manufacturing process, the period should ideally not be longer than necessary. The inventors have found that adequate binder burnout may take place during the time intervals specified above. These time durations are sufficient to provide improved, such as essentially full, binder burnout while maintaining a low enough temperature to avoid effects of overheating the binder material.

[0459] It is generally to be understood that it is desired to obtain a cover with solidified solder material at the cover that is substantially, such ass almost completely, free from material that may outgas into the evacuated gap of the VIG unit assembly at the moment of sealing the through hole where the solidified solder material is re-softened to seal the through hole. If the solder material at the cover outgasses material into the evacuated gap, the integrity, such as low pressure, of the final VIG unit may be reduced. In one or more embodiments of the fifth aspect, the one or more covering body workpieces is / are in a reduced atmosphere during the binder burnout temperature holding period.

[0460] A reduced pressure, such as a vacuum, may aid in removing the binder gasses evaporating from the seal material during the binder burnout temperature holding period. The evaporation rate is generally affected by the partial pressure of a species in the surroundings. In the case of a reduced overall pressure, the partial pressure is similarly reduced, which causes an increased evaporation rate at a given temperature. Additionally or alternatively, the pressure within the working chamber may be controlled to aid in reducing the size and / or quantity of bubbles in the seal material. For example, a relatively quick change between a reduced pressure and ambient pressure may cause bubbles in the surface of the seal material to burst.

[0461] In one or more embodiments of the fifth aspect, the one or more covering body workpieces are at atmospheric pressure during the controlled, such as constant, binder burnout temperature holding period.

[0462] Atmospheric pressure may limit the quantity and size of bubbles formed in the surface of the seal material compared to reduced pressure. Additionally or alternatively, the active gaseous species in the ambient atmosphere, such as oxygen, may provide desired properties when interacting with the surface and / or binder of the heated seal material.

[0463] In one or more embodiments of the fifth aspect, said cooling of the one or more heated covering body workpieces and seal material comprises a controlled, cooling, such as according to a cooling program. In someembodiments hereof, the cooling m,ay comprise a controlled, stepwise cooling.

[0464] In one or more embodiments of the fifth aspect, said controlled cooling is provided over a duration of at least 2 hours, such as at least 6 hours, such as at least 10 hours. In one or more embodiments of the fifth aspect, said controlled cooling is provided over a duration in the range of 2 - 24 hours, such as in the range of 6 - 18 hours, such as in the range of 10 - 14 hours.

[0465] In one or more embodiments of the fifth aspect, said controlled cooling is provided over a duration of less than 24 hours, such as less than 18 hours, such as less than 14 hours.

[0466] In one or more embodiments of the fifth aspect, said cooling of the one or more heated covering body workpieces and seal material comprises a controlled, such as constant, cooling temperature holding period.

[0467] In one or more embodiments of the fifth aspect, the controlled, such as constant, cooling temperature holding period has a duration of at least 2 hours, such as at least 6 hours, such as at least 10 hours, In one or more embodiments of the fifth aspect, the controlled, such as constant, cooling temperature holding period has a duration in the range of 2 - 24 hours, such as in the range of 6 - 18 hours, such as in the range of 10 - 14 hours. In one or more embodiments of the fifth aspect, the controlled, such as constant cooling temperature holding period has a duration of less than 24 hours, such as less than 18 hours, such as less than 14 hours.

[0468] The cooling step may be at a temperature where the seal material is allowed to equilibrize into a desired intrinsic structure and / or macroscopic shape. A cooling temperature holding period may additionally or alternatively alleviate stresses in the seal material that might otherwise cause a poor seal quality and / or make the seal more prone to cracks.

[0469] A prolonged cooling temperature holding period may be favorable in order to provide an improved seal material, such as substantially stress-free, solidified solder material and covering body workpiece. Additionally or alternatively, a long cooling temperature holding period may provide a solidified seal with the appropriate intrinsic structure and / or macroscopic shape on the covering body workpiece. In one or more embodiments of the fifth aspect, the one or more covering body workpieces are in a reduced atmospheric pressure during the controlled cooling, such as during the controlled, such as constant, cooling temperature holding period.

[0470] A reduced atmosphere may provide a favorable surface chemistry I microstructure of the solidified seal material. Additionally or alternatively, it may provide a better environment for removing trace amounts of gasses developed inside the seal material at the target temperature and / or cooling temperature. A reduced pressure surrounding the seal material may provide a more rough surface if bubbles formed during outgassing are not burst. This may for example be favorable for providing a large surface roughness during the step of evacuating the VIG unit.This may help to provide a surface topology providing gas passages that may be used during gap evacuation while the seal material support on a surface.

[0471] In one or more embodiments of the fifth aspect, the one or more covering body workpieces are at atmospheric pressure during the controlled cooling, such as during the controlled, such as constant, cooling temperature holding period.

[0472] Atmospheric pressure and / or the active species in ambient air may provide a more favorable surface structure, such as reduce the quantity and / or size of bubbles at the surface.

[0473] In one or more embodiments of the fifth aspect, said heating of the glass solder material during the heating time, such as until the target temperature is reached, comprises subjecting the one or more covering body workpieces to an active gas, such as a noble gas, such as ozone.

[0474] In one or more embodiments of the fifth aspect, said heating of the seal material at the target temperature, comprises subjecting the one or more covering body workpieces (21) to an active gas, such as ozone.

[0475] In one or more embodiments of the fifth aspect, said manufacturing comprises subjecting the one or more covering body workpieces to an active gas, such as ozone.

[0476] A specialized gas may be used to obtain a desired surface chemistry I microstructure. For example, a gas may be selected that interacts with the surface of the seal material to produce a high surface roughness. Alternatively, a gas may be selected to provide a more smooth surface. This specialized gas may be introduced at various periods of the heating, such as before, during, and / or after the covering body workpieces have reached the target temperature. It may be introduced for a number of cycles, where the specialized gas is flushed out with another gas species and / or by pumping the working chamber to a reduced pressure. Changes in pressure may also serve to interact with the heated seal material, for example by bursting bubbles formed in the surface.

[0477] In one or more embodiments of the present disclosure, heating of the seal material at the target temperature, comprises subjecting the one or more covering body workpieces to an active gas, such as ozone.

[0478] In one or more embodiments of the fifth aspect, the step of obtaining one or more covers comprises providing one or more protrusions and / or one or more gaps, such as recesses, in a side surface of the covering body.

[0479] Such protrusions may provide a simple means of centering the cover inside a larger diameter recessed part of the through hole of the first glass sheet. Additionally or alternatively, they may provide a space between the cover side surface and the side surface of the recessed part, which may aid in providing an efficient evacuation of the VIG unit gap. The protrusions may be integrally connected to the covering body, such as where they are made of the same glass sheet that is cut so as to provide the protrusions. Alternatively, they may be provided by a material that is added to the glass sheet of the covering body. This material may for example be a glass solder material. The protrusions may stretch the entire height of the covering body. Alternatively, they may be provided for only part of the height. In any case, they are able to provide the additional space between the covering body and the side of a recessed part of the glass sheet of the VIG unit as well as provide a centering effect of the covering body. Protrusions may favorably be provided at locations not corresponding to channels in the solidified solder material if such exist.

[0480] Gaps may be provided in order to ensure sufficient space for efficient evacuation of the VIG unit gap. They may favorably be provided at locations corresponding to channels in the solidified solder material if such exist. This is in order to provide a continuous channel for the air to pass through the step of evacuating the gap. The gaps are understood to e.g. stretch across the entire height of the covering body between major surfaces thereof.

[0481] In one or more embodiments of the fifth aspect, the step of obtaining one or more covers comprises providing three or more protrusions in the side surface of the covering body.

[0482] In one or more embodiments of the fifth aspect, the step of obtaining one or more covers comprises providing three or more recesses), such as gaps in the side surface of the covering body.

[0483] Three or more protrusions may provide a centering effect across the entire perimeter of the covering body. Additionally, it may leave sufficient space for more effective evacuation between the protrusions.

[0484] In one or more embodiments of the fifth aspect, said protrusions and / or gaps in the side surface of the covering body are located equidistantly from each other around the perimeter of the covering body.

[0485] Equidistant protrusions may provide a centering effect in all lateral directions.

[0486] Furthermore, equidistant protrusions and / or gaps may provide a balanced evacuation, where the air streams that pass around the cover do so homogeneously around the perimeter of the cover and therefore do not push the cover to any particular side. Additionally or alternatively, equidistant protrusions and / or gaps may correspond to locations of channels in the solidified seal material.

[0487] In one or more embodiments of the fifth aspect, the covering body of each obtained cover has a polygonal cross section, such that each protrusion is provided by a vertex of said polygon and each gap is provided by an edge of said polygon.

[0488] This design of the covering body provides an alternative to a circular shape with protrusions and / or gaps cut out of / into, respectively. In order to be suitable, a polygonshaped covering body must be characterized such that an inscribed circle of the polygon is larger than the smaller diameter portion of the through hole of the first glass sheet so as to actually cover it. Additionally, the covering body must be large enough that the inscribed circle is sufficiently larger than the smaller diameter portion of the through hole that seal material can be provided all around the circumference of the through hole - ideally without flowing into the smaller diameter portion and into the gap.

[0489] In one or more embodiments of the fifth aspect, each protrusion and / or each gap in the side surface of the covering body has a semicircular cross section.

[0490] If the covering bodies are obtained, such as e.g. cut, from a glass sheet by means of laser cutting, programming a semicircular shape of the protrusions and / or gaps may be a simple way of achieving these structures. Similarly, a semicircular channel may be an ideal structure for ensuring optimized air flow. Alternatively, the protrusions and / or gaps may be elliptical, polygonal, and / or irregularly shaped.

[0491] In one or more embodiments of the fifth aspect, the radius of the semicircular cross section is in the range of 1 - 20%, such as 2 - 15%, such as 5 - 10% of a width of the covering body surface comprising the solder material (22), and / or the radius of the semicircular cross section is in the range of 0.1 - 1.5 mm, such as in the range of 0.2 - 1.0 mm, such as in the range of 0.3 - 0.7 mm.

[0492] The protrusions may preferably be large enough to ensure a space between the side surface of the covering body and the side surface larger diameter portion of the through hole. Similarly, the gaps may preferably be large enough to ensure an efficient evacuation. On the other hand, the protrusions and / or gaps should be sized so that there is still sufficient overlap between the covering body and the floor of the large- diameter portion of the through hole to create a strong and durable seal.

[0493] In one or more embodiments of the present disclosure, the step of arranging the cover in the larger diameter portion of the through hole in the first glass sheet provides a maximum distance between a side surface of the covering body and a side surface (10bs) of the larger diameter portion of at least 2%, such as at least 4%, such as at least 6% of a width of the covering body surface comprising the solder material, and / or wherein the step of arranging the cover in the larger diameter portion of the through hole in the first glass sheet provides a maximum distance between a side surface of the covering body and a side surface (10bs) of the larger diameter portion of at least 0.2 mm, such as at least 0.4 mm, such as at least 0.5 mm. Additionally or alternatively, the step of arranging the cover in the larger diameter portion of the through hole in the first glass sheet provides a maximum distance between a side surface of the covering body and a side surface of the larger diameter portion of at least 10%, such as at least 15%, such as at least 20% of the diameter of the smaller diameter portion of the through hole.

[0494] The cover manufacturing may be a batch manufacturing. In other embodiments, it may be a continuous process manufacturing.

[0495] In one or more embodiments of the present disclosure, said obtaining of one or more covers from the cooled covering body workpieces may comprise providing a plurality of covers from a single covering body workpiece of the one or more covering body workpieces, such as by means of a cutter, such as by means of a laser. Each cover obtained from said covering body workpiece comprises said solidified glass solder material. Hence, a plurality of covers may be obtained from a single workpiece after the workpiece has been heated in the working space. This may e.g. provide a faster and / or efficient and / or cost efficient manufacturing of covers for subsequent use during sealing of an evacuated gap to obtain a vacuum insulated glass unit.

[0496] It is generally understood that in some embodiments of the present disclosure, the covering body workpiece may comprise or consist of a glass body such as an annealed glass body or a chemically hardened glass body, or it may comprise or consist of a metal body.

[0497] For example, such materials may be more easy to cut after the seal material has been solidified.

[0498] Annealed glass material may also be advantageous to work with compared to e.g. thermally tempered glass sheets when working with smaller parts. Annealed glass material can also resist a higher temperature for a longer time when compared to tempered glass sheets.

[0499] It is generally understood that glass material such as the solder glass material and / or a covering body comprising glass material such as annealed glass may comprise an advantageous coefficient of thermal expansion (CTE), which may be advantageous to match with the VIG unit glass sheet comprising the evacuation hole.

[0500] In one or more embodiments of the present disclosure, the seal material at one or more of the one or more covering body workpieces may comprise or consist of a continuous layer of seal material, such as a continuous layer of the glass solder material, A plurality of covers may be obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a seal material originating from the continuous layer of seal material.

[0501] In some embodiments of the present disclosure, the seal material at one or more of the one or more covering body workpieces may comprise or consist of a plurality of discretely arranged portions of seal material which are distributed across a surface of the workpiece, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a solidified seal material, wherein the solidified seal material of the cover comprises at least one of said discretely arranged solidified portions of the seal material. This may e.g. provide a fast and / or cost efficient manufacturing of covers.

[0502] In some embodiments of the present disclosure, said providing of the one or more covering body workpieces may comprise providing a plurality of individual covering body workpieces, wherein each individual covering body workpiece comprises a portion of said seal material to be heated. In some embodiments, said individual covering body workpieces may each be configured to constitute a cover, such as a single cover, when the seal material has been solidified.

[0503] This may e.g. provide a more cost efficient and / or fast cover manufacturing. Providing a plurality, such as at least 5, at least 20, at least 50 or at least 100, work pieces in the working space, such as a working chamber, such as in a vacuum chamber, at once may provide a more cost efficient and / or fast cover manufacturing.

[0504] In one or more embodiments of the fifth aspect, the method comprises obtaining a plurality of covers from the cooled covering body workpiece, such as by means of cutting, wherein each obtained cover comprises a portion of said solidified seal material. Alternatively, each workpiece may have the desired covering body shape and size already when the heating of the solder to provide binder burnout is initiated.

[0505] The present disclosure moreover relates, in a sixth aspect, to a covering body workpiece for use for manufacturing one or more covers for use during sealing of an evacuated gap of a vacuum insulated glass unit. The one or more covers may e.g. be a cover as described above according to various embodiments of the present disclosure. The covering body workpiece comprises a glass body and a seal material comprising a seal material pre-form, which pre-form comprises a glass solder material, such as glass frit solder material, arranged at a major surface of the one or more covering body workpieces, such as arranged on a major glass surface of the glass body or on a surface of a primer arranged between the glass body and the glass solder material. The glass transition temperature of the glass solder material is lower than the glass transition temperature of the covering body workpiece. The workpiece may comprise one or more predefined evacuation channels having a channel width, which channel width extends between opposing walls of the seal material, wherein each of the one or more predefined evacuation channels extends, such as from a center area, in an evacuation direction. Optionally, the glass solder material may be configured to cover at least 40%, such as at least 50%, such as at least 60%, such as at least 70%, of the area of the final major cover surface of the cover.

[0506] This has shown to provide a good tradeoff between cover size and obtaining strong bonding of the solder material when the final cover is used for sealing an evacuated gap of a VIG unit. Also it has been shown that such a covering body comprising a glass solder material pre-form as described above may be especially suitable for obtaining a cover with heat treated solidified solder material for subsequent use for sealing the through hole of an evacuated gap, where the solidified solder material may comprise an advantageous solder material shape for obtaining an advantageous flow of evacuated gas during gap evacuation and / or for gap sealing.

[0507] It is understood that the workpiece may comprise a single pre-form or a plurality of preforms of solder material. In case of a plurality of pre-forms, the workpiece may be cut into a plurality of individual covers so as to obtain a covering body comprising solder material, either before or after heat treating the solder material as e.g. described above according to various embodiments of the present disclosure. In one or more embodiments of the sixth aspect, the seal material of the seal material pre-form comprises between 0.1 - 30 wt%, such as 1 - 15 wt%, such as between 2-10 wt% binder material configured for subsequent burnout.

[0508] In one or more embodiments of the sixth aspect, the seal material of the seal material pre-form comprises between 1.5 -8 wt%, such as between 2 - 6 wt%, binder material configured for subsequent burnout.

[0509] The binder material may e.g. help to improve manufacturability and seal quality, for example before and / or during thermal processing and / or provide a paste that is easy to apply to the surface of the covering body workpiece. This binder may be substantially removed to create a hardened solidified seal that can be reheated to provide a hermetic sealing of the pump-out port during manufacturing of the VIG unit.

[0510] In one or more embodiments of the sixth aspect, the length of each of the one or more predefined evacuation channels is longer than it is wide. This may e.g. enable obtaining an advantageous, such as narrow, predefined channel for use during gap evacuation. Also, experiments have shown that it may enable providing an advantageous evacuation channel after solidifying the solder material, e.g. as described above and / or below.

[0511] In one or more embodiments of the sixth aspect, the height of the one or more evacuation channels is at least 30%, such as at least 80%, such as at least 90%, for example substantially 100%, of the height of the solidified solder material. This may e.g. enable obtaining an advantageous, such as narrow, predefined channel for use during gap evacuation.

[0512] In one or more embodiments of the sixth aspect, wherein the height of the seal material of the pre-form is between 0.4 - 1.3 mm, such as between 0.5 - 1 m, such as between 0.6-0.8 mm. This may help to obtain a solidified solder material that is an advantageous tradeoff between saving solder material, obtaining a strong bond between cover and VIG unit, obtaining a space saving solution and e.g. also reducing the amount of solder material, or avoiding solder material running into the through hole, such as a smaller diameter through hole. In one or more embodiments of the sixth aspect, the seal material pre-form is a hardened seal material, e.g. comprising less than 8 wt%, such as less than 5 wt% or less than 1 wt% solvent, for example wherein the seal material preform is a dried out seal material preform. This may e.g. enable easy handling and / or enable advantageous subsequent processing, such as binder burnout.

[0513] In one or more embodiments of the sixth aspect, said glass solder material of the seal material pre-form is shaped so that glass solder material is omitted at a center area of the major cover surface, and wherein the glass solder material of the seal material preform comprises opposing walls facing a space located opposite to the center area.

[0514] This may e.g. help to reduce the amount of solder material and / or help to avoid solder material running into the through hole, such as a smaller diameter through hole, when the final cover is used for sealing a through hole to obtain a hermetically sealed evacuated gap of a VIG unit.

[0515] In one or more embodiments of the sixth aspect, the covering body workpiece comprises at least one, such as at least two, such as at least three, of the previously described predefined channels.

[0516] This may enable obtaining a cover facilitating improved gap evacuation. Also, more evacuation channels, such as at least two or three predefined evacuation channels, may enable providing more narrow individual predefined channels, helping to collectively enhance gas evacuation, such as helping to reduce flow resistance, while enabling improved and / or more consistent closing of the channel space when the (solidified) solder material is heated to soften it with the purpose of sealing a through hole to seal the evacuated gap of a VIG unit.

[0517] In one or more embodiments of the sixth aspect, said glass body is a structural glass body, such as an annealed glass body.

[0518] A glass body may provide desired advantages, such as temperature resistance and / or improved matching of coefficient of thermal expansion CTE with the CTE of the glass solder material of the cover. In one or more embodiments of the sixth aspect, the thickness of the glass body is between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm, such as between 1.8 mm and 2.1 mm, endpoints included.

[0519] By the above mentioned dimensions, e.g. one or more advantages mentioned above and / or below may be obtained.

[0520] In one or more embodiments of the sixth aspect, the total volume of said glass solder material of the seal material pre-form at the major cover surface is at least 10 mm2, such as at least 15 mm2, such as at least 19 mm2. In one or more embodiments of the sixth aspect, the total volume of said glass solder material at the major cover surface is less than 40 mm2, such as less than 30 mm2, such as less than 25 mm2. In one or more embodiments of the sixth aspect, the total volume of said solidified solder material at the major cover surface is in the range of 10 mm2- 40 mm2, such as in the range of 15 mm2- 30 mm2, such as in the range of 19 mm2- 25 mm2.

[0521] This volume has shown to allow shrinkage and binder burnout of the glass solder material, e.g. when heating the solder material pre-form in order to obtain a cover with solidified solder material for subsequent use having an advantageous facilitating advantageous gas evacuation and / or sealing of the through hole to seal an evacuated gap to obtain a VIG unit.

[0522] In one or more embodiments of the sixth aspect, the minimum cross sectional area of each of the one or more predefined channels, is less than 3 mm2, such as less than 2.5 mm2, such as less than 1.5 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction of the evacuation channel. In some embodiments, the when the cross sectional area may be determined when covering body workpiece is arranged so that the surface of the glass solder material supports on a surface of a glass sheet.

[0523] In one or more embodiments of the sixth aspect, the minimum cross sectional area of each of the one or more channels, for example when the covering body workpiece is arranged so that the surface of the glass solder material supports on a surface of a glass sheet, is at least 0.08 mm2, such as at least 0.1 mm2, such as at least 0.2 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction of the evacuation channel. In one or more embodiments of the sixth aspect, the minimum cross sectional area of each of the one or more channels, for example when the covering body workpiece is arranged so that the surface of the glass solder material supports on a surface of a glass sheet, is in the range of 0.08 - 3 mm2, such as in the range of 0.1 - 2.5 mm2, such as in the range of 0.2 -1.5 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction of the evacuation channel.

[0524] In one or more embodiments of the sixth aspect, the minimum cross sectional area of each of the one or more channels, for example when the covering body workpiece is arranged so that the surface of the glass solder material supports on a surface of a glass sheet, is in the range of 0.4 - 0.9 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction of the evacuation channel.

[0525] This / these channel dimensions may help to provide a cover that is suitable for subsequent solidification of the pre-shape which provides an advantageous tradeoff between enabling advantageous gap evacuation, such as reducing flow resistance, and assuring consistent and efficient closure of the through hole when the VIG unit assembly gap has been evacuated.

[0526] In one or more embodiments of the sixth aspect, the evacuation channel height, such as the minimum height, is larger than the width, such as the minimum width, of the evacuation channel.

[0527] In one or more embodiments of the sixth aspect, the evacuation channel height, such as minimum evacuation channel height, is within ±70%, such as within ±50%, such as within ±30% of the evacuation channel width, such as the minimum evacuation channel width.

[0528] In one or more embodiments of the sixth aspect, the maximum evacuation channel height is within ±70%, such as within ±50%, such as within ±30% of the evacuation channel width, such as the maximum evacuation channel width or minimum evacuation channel width. In one or more embodiments of the sixth aspect, the glass solder material comprises at least one portion of solder material, such as at least two portions of solder material, wherein the minimum width of the glass solder material, excluding the area of the one or more evacuation channels, is at least 1.4 mm, such as at least 1.6 mm, such as at least 1.8 mm.

[0529] In one or more embodiments of the sixth aspect, the seal material comprises one or more inorganic oxides selected from the group of oxides of Li, B, Na, Mg, Al, Si, P, K, V, Mn, Zn, Rb, Ag, Sn, Te, Ba and / or Bi. In one or more embodiments of the sixth aspect, the glass seal material comprises one or more oxides of Te and / or V, such as comprising one or more of V2O5, VO2, and / or V2O3 in combination with TeC>2, TeCL, TeCh, and / or TesCL.

[0530] In one or more embodiments of the sixth aspect, the glass solder material comprises more tellurium oxide than vanadium oxide by weight.

[0531] In one or more embodiments of the sixth aspect,, wherein the glass solder material comprises, such as additionally, one or more of AI2O3, SiC>2, MgO, P2O5, Bi20s, ZnO, Nb2C>5, Ag2O, and / or MnO.

[0532] In one or more embodiments of the sixth aspect, the glass solder material comprises Bi2C>3 in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0533] By using a solder material as e.g. described above, one or more advantages as described above and / or below may be obtained.

[0534] In one or more embodiments of the sixth aspect, the seal material of the cover comprises at least one primer layer positioned between the glass solder material and the glass body.

[0535] Hereby one or more advantages as described above and / or below may be obtained.

[0536] In one or more embodiments of the sixth aspect, said covering body workpiece comprises a plurality of discrete portions of said glass solder material, such as discrete groups of glass solder material, and wherein the covering body workpiece is configured for subsequent cutting so as to obtain a plurality of covers, each cover comprising a portion or a group of portions of glass solder material and preferably also one or more of said evacuation channels.

[0537] The present disclosure additionally, in seventh aspect, relates to a method of manufacturing one or more covers for subsequent use during sealing of an evacuated gap of a vacuum insulated glass unit, wherein said method comprises:

[0538] - providing one or more covering body workpieces, wherein said one or more covering body workpieces comprises a seal material comprising a glass solder material, wherein the seal material is arranged at a surface of the one or more covering body workpieces,

[0539] - arranging the one or more covering body workpieces in a working space,

[0540] - heating the seal material in the working space to a target temperature by means of a heater, wherein said heating is provided so as to provide an outgassing of the glass solder material,

[0541] - cooling the one or more heated covering body workpieces and seal material so as to solidify the seal material,

[0542] - obtaining one or more covers from the one or more cooled covering body workpieces, wherein the method may further comprise shaping the solidified seal by means of a shaping tool.

[0543] A separate step of shaping the solidified solder material may provide a more precise and / or an optimized shape of the solidified solder material before the step of evacuating and sealing the gap of the VIG unit.

[0544] As an alternative or additional step to modifying the solidified seal material, it may also be possible and favorable to shape the seal material before heating the covering body workpieces to sinter and solidify the seal material. In this state, the seal material may be in the form of a paste, where it may be easy to shape it in one way or another. However, the step of heating the covering body workpieces may alter the shape of the seal material as the binder evaporates and the seal material softens at the target temperature. Therefore, it may be favorable to additionally or only shape the seal material after solidification. In one or more embodiments of the seventh aspect, said shaping of the solidified seal by means of the shaping tool comprises shaping, such as re-shaping, at least a part of the surface of the solidified solder material that faces away from the covering body workpiece or covering body.

[0545] This surface will face the floor of the larger diameter portion of the through hole when the cover is placed inside this portion during the step of evacuating and sealing the gap of the VIG unit. It may therefore be relevant to shape the surface so as to provide an optimized evacuation and sealing process. For example, it may be relevant to shape a number of channels in the solidified solder material that will provide an efficient air flow during the evacuation step.

[0546] In one or more embodiments of the seventh aspect, said shaping of the solidified seal by means of the shaping tool is provided before or after the one or more covers is / are obtained, such as cut from, the one or more covering body workpieces.

[0547] In one or more embodiments of the seventh aspect, said shaping of the solidified seal by means of the shaping tool comprises cutting, such as laser cutting, mechanically cutting or etching into the solidified seal material.

[0548] Cutting may preferably take place in an isolated atmosphere, such as a fume hood or a similarly ventilated room / compartment. This may for example be relevant if the solidified solder material comprises toxic components that may outgas and / or pulverize during the step of cutting.

[0549] The laser used for cutting may be a continuous wave laser or it may be a pulsed, such as a nanosecond, laser. It may be a visible light laser or an infrared laser. The laser power may be varied during the cutting process so as to form structures in the seal material of various heights and / or surface topology.

[0550] In one or more embodiments of the seventh aspect, said shaping of the solidified seal by means of the shaping tool comprises shaping, such as cutting, one or evacuation channels into the surface of the solidified seal.

[0551] Evacuation channels may provide a more efficient evacuation means by reducing the resistance to air flow. The evacuation channels are generally understood to span the entire height of the solder material or be only partway cut into the solidified seal material. The evacuation channels may extend from a center portion and to the outer periphery of the final cover. In some embodiments, the cross sectional area of the shaped channel(s) may be the same or smaller than the cross sectional area of a predefined channel as described above according to various embodiments of the present disclosure.

[0552] In one or more embodiments of the seventh aspect, the one or more shaped evacuation channel(s) is shaped by the shaping tool so as to extend along a predefined paths, such as linear path, such as between an inner side boundary of the solidified solder material and an outer side boundary of the solidified solder material.

[0553] A direct channel from the lower diameter portion of the through hole to the side surface of the covering body will be an efficient flow direction for air exiting the gap of the VIG unit. This may therefore provide a solution with a low air resistance and therefore an efficient evacuation.

[0554] In one or more embodiments of the seventh aspect, said shaping of the solidified seal comprises modifying the surface roughness, such as by means of polishing.

[0555] The air flow across the interface between the covering body and the floor of the larger diameter portion of the through hole is determined by the surface roughness of the solidified solder material in addition to any evacuation channels. By manipulating the surface roughness, the direction of the air flow during evacuation can be controlled.

[0556] In one or more embodiments of the seventh aspect, said shaping of the solidified seal comprises increasing the surface roughness of the solidified solder material so as to provide a surface roughness in order to reduce the flow resistance when the solidified solder material supports on a glass sheet surface during evacuation of a gap of a VIG unit assembly. By providing a large surface roughness, it may be possible to reduce the size and / or number of evacuation channels, either defined by the mold of the applied solder material applied prior to manufacturing the covers and / or provided by shaping the solidified seal material. Alternatively, a high surface roughness may enable a complete elimination of such evacuation channels if the passages for air flow introduced by the surface structures are sufficient to provide a good and relatively fast evacuation.

[0557] In one or more embodiments of the seventh aspect, said shaping of the solidified seal comprises shaping the solidified solder material so as to reduce the flow resistance when the solidified solder material supports on a glass sheet surface during evacuation of a gap of a VIG unit assembly. The glass sheet surface may be the floor of the larger diameter portion of the through hole or it may be directly on top of the first glass sheet surrounding a non-recessed through hole.

[0558] In one or more embodiments of the seventh aspect, said shaping of the solidified seal is initiated based on a quality assurance inspection, such as an automated quality assurance inspection. The step of heating the covering body workpieces may introduce variations in the shape of the solidified seal material. This may for example be brought about by inhomogeneities in heating and / or solder material composition across a covering body and between different covering bodies. Therefore, it may be advantageous to pass each covering body through an inspection to ensure that it lies within expected ranges of shape and / or volume.

[0559] In one or more embodiments of the seventh aspect, the quality assurance inspection comprises the use of a camera. Each cover may be imaged by an automated camera system. The camera may be a digital camera with a chip that is sensitive to visible light.

[0560] In one or more embodiments of the seventh aspect, said quality assurance inspection comprises comparing, such as correlating, each cover, such as a measured or calculated seal material topology representation, with a predefined standard, such as a representation of a predefined, desired surface topology. A set of predetermined standards may be stored in a database that is checked against each cover that is inspected. This may be done by means of computer algorithms, such as simple logic I decision trees.

[0561] In one or more embodiments of the seventh aspect, the step of comparing each covering body to a set of predefined standards comprises the use of artificial intelligence, such as machine learning and / or computer vision. Computer vision may be able to implement more complex decisions than simple logic I traditional computer algorithms. Additionally or alternatively, artificial intelligence models may be continuously updated based on feedback from the production line for the covers that are inspected and subsequently used to manufacture VIG units. This may provide a dynamic and up-to-date model for quality assurance and / or shaping of the solidified seal material. In one or more embodiments of the seventh aspect, wherein the solidified glass solder material comprises one or more inorganic oxides selected from the group of oxides of Li, B, Na, Mg, Al, Si, P, K, V, Mn, Zn, Rb, Ag, Sn, Te, Ba and / or Bi, such as wherein the glass seal material comprises one or more oxides of Te and / or V, such as comprising one or more of V2O5, VO2, and / or V2O3 in combination with TeC>2, TeCL, TeCh, and / or TesCL. These oxides may be known in various combinations as low- temperature solder glass materials.

[0562] Tellurium / Vanadium (Te / V) low-temperature glass solder materials may have a glass transition temperature and melting temperature substantially lower than the corresponding values for soda-lime glass. For example, Te / V solder glass materials may have glass transition temperature and melting temperature below the range of temperatures, where thermally tempered soda-lime glass is known to quickly detemper. For example, the Te / V-based solder glass material disclosed in US 2024 / 0167328 A1 has a glass transition temperature of 290 °C and a melting temperature of 390 - 395 °C.

[0563] In one or more embodiments of the seventh aspect, the solidified glass solder material comprises more tellurium oxide than vanadium oxide by weight.

[0564] In one or more embodiments of the seventh aspect, the solidified glass solder material additionally comprises one or more of AI2O3, SiC>2, MgO, P2O5, Bi20s, ZnO, Nb20s, Ag2O, and / or MnO. Additives, such as additional oxides, may help to adjust the properties of the solder glass material to better suit the requirements of a given application, such as for sealing the through hole of a vacuum-insulated glass unit.

[0565] In one or more embodiments of the seventh aspect, the solidified glass solder material (22) comprises Bi2C>3,such as in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3. Bismuth (Bi)-based solder glass materials are considered less toxic or non-toxic alternatives to e.g. lead (Pb)-containing compositions or Te / V glass solder materials. Known Bi-based solder glass materials have a higher glass transition temperature and melting temperature than e.g. Te / V materials.

[0566] Boron (B)-based solder glass materials have been described in prior art as non-toxic alternatives to e.g. lead (Pb)-containing compositions or Te / V glass solder materials. Known B-based solder glass materials have a higher glass transition temperature and melting temperature than e.g. Te / V materials.

[0567] In one or more embodiments of the seventh aspect, said method is part of a method according to any of the preceding aspects of embodiments described above.

[0568] The present disclosure additionally, in an eighth aspect, relates to a cover for use during sealing a through hole of an evacuated gap of a vacuum insulated glass unit, wherein said cover comprises:

[0569] - a covering body,

[0570] - a major cover surface at a solder side of the cover,

[0571] - a seal material comprising a glass solder material, wherein the glass transition temperature of the glass solder material is lower than the glass transition temperature of the covering body, wherein the seal material moreover comprises a primer layer, such as a single primer layer or a multilayer primer layer, arranged between the solder material and the covering body.

[0572] This may e.g. provide an improved cover. The primer layer may e.g. act as absorbers during the local heating of the solder material. Additionally or alternatively, the primer layer(s) may provide a better match between properties, such as glass transition temperature and / or thermal expansion coefficient of the covering body and the solder material. Additionally or alternatively, the primer layer may allow the construction of a more inexpensive VIG unit as glass frit used for primer may be less expensive than the solder material. It is generally understood that one or more advantages of a cover comprising a primer are described further above.

[0573] In one or more embodiments of the eighth aspect, the primer layer is arranged so as to cover substantially the whole major surface of the covering body.

[0574] In one or more embodiments of the eighth aspect, the primer layer is arranged so as to cover at least the same area of the major surface of the covering body as is covered by the solder material. In one or more embodiments of the eighth aspect, the primer layer is arranged so as to cover the whole major surface of the covering body except a center area. In some embodiments hereof, the primer layer may form a ring around the center area.

[0575] This may e.g. provide an advantageous cover, such as a cover where flow of the solder material during cover use is more controlled. It may also provide a more cost efficient cover.

[0576] In one or more embodiments of the eighth aspect, the primer layer has a height in the range of 10 - 100 pm, such as in the range of 20 - 80 pm, such as in the range of 30 - 50 pm. In one or more embodiments of the eighth aspect, the primer layer has a height of at least 10 pm, such as at least 20 pm, such as at least 30 pm. In one or more embodiments of the eighth aspect, the primer layer has a height of no more than 100 pm, such as no more than 80 pm, such as no more than 50 pm. This may e.g. provide a space saving and / or cost efficient solution. In other embodiments, the primer layer may be thicker.

[0577] In one or more embodiments of the eighth aspect, the primer layer comprises a material with a glass transition temperature Tg that is lower than the glass transition temperature of the covering body and higher than the glass transition temperature of the seal material. This may help to match properties and enable obtaining an improved cover.

[0578] In one or more embodiments of the eighth aspect, the primer layer comprises a material with a softening point, such as Littleton softening point, that is lower than the softening point, such as Littleton softening point, of the covering body and higher than the softening point, such as Littleton softening point, of the solder material.

[0579] In one or more embodiments of the eighth aspect, the primer layer covers between 50% and 100%, such as between 70% and 100%, such as between 70% and 93% of the major surface of the covering body.

[0580] In one or more embodiments of the eighth aspect, the primer layer covers an area that is larger, such as at least 5% larger, such as at least 15% larger or at least 20% larger than the area covered by the solidified solder material. In one or more embodiments of the eighth aspect, the cover comprises one or more predefined evacuation channels having a channel width, which channel width extends between opposing walls of the solder material.

[0581] In one or more embodiments of the eighth aspect, each of the one or more predefined evacuation channels extends in an evacuation direction, such as radially towards the outer periphery of the cover,

[0582] In one or more embodiments of the eighth aspect, the glass solder material covers at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface.

[0583] In one or more embodiments of the eighth aspect, the glass solder material is a solidified glass solder material, such as a solidified glass solder material that has been obtained by means of heating the solder material to obtain binder burnout, softening the solder material and then cooling the solder material to solidify it.

[0584] In one or more embodiments of the eighth aspect, the cover is a cover according to one or more of the previously described aspects and / or embodiments.

[0585] In one or more embodiments of the eighth aspect, the cover is manufactured by means of a method according to one or more embodiments and / or aspects described above, such as one or more embodiments of the fifth aspect.

[0586] The present disclosure moreover relates, in a ninth aspect, to use of a cover, such as one or more embodiments of the first aspect, for covering and sealing of an evacuation hole in a glass sheet of a vacuum insulated glass unit so as to seal an evacuated gap of a vacuum insulated glass unit.

[0587] The present disclosure moreover relates, in a tenth aspect, to a building window, such as a roof window, wherein the building window comprises a window frame which supports a VIG unit according to one or more embodiments or aspects described above. The present disclosure moreover relates, in a eleventh aspect, to a method of manufacturing one or more covers for use, such as subsequent use, during sealing of an evacuated gap of a vacuum insulated glass unit, wherein said method comprises:

[0588] - providing a covering body workpiece, wherein the covering body workpiece comprises a seal material, wherein the seal material is arranged at a surface of the covering body workpiece,

[0589] - arranging the workpiece in a working space,

[0590] - heating the seal material in the working space to a target temperature by means of a heater,

[0591] - cooling the covering body workpiece and seal material so as to solidify the seal material,

[0592] - obtaining a plurality of covers from the cooled covering body workpiece, such as by means of cutting, wherein each obtained cover comprises a portion of said solidified seal material.

[0593] This may e.g. provide a cost efficient, simple and / or and fast manufacturing of covers which are suitable for use during sealing of an evacuated gap of a VIG unit. The heating in the working space may e.g. provide an improved cover, e.g. as described above and / or below.

[0594] In some embodiments of the eleventh aspect, the seal material may comprise a glass solder material.

[0595] In one or more embodiments of the eleventh aspect, the heating of the seal material in the working space is provided so as to provide an outgassing of the glass solder material. This may e.g. provide a cover where the seal material provides less outgassing when the cover is used for sealing a VIG unit gap. Additionally or alternatively, it may enable providing a more dense seal material.

[0596] In one or more embodiments of the eleventh aspect, the seal material at the covering body workpiece may comprise or consist of a continuous layer of seal material, such as a continuous layer of the glass solder material, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a seal material originating from the continuous layer of seal material. This may e.g. enable a more simple cover manufacturing and / or enable providing a larger more plane solidified seal material surface, since the solidified seal material of the work piece is cut by means of a cutter.

[0597] In one or more embodiments of the eleventh aspect, the seal material at the covering body workpiece may comprise or consist of a continuous layer of a primer material, such as a continuous layer of the glass solder material, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a seal material originating from the continuous layer of seal material.

[0598] This may e.g. enable a more simple cover manufacturing and / or enable providing a larger more plane solidified seal material surface, since the solidified seal material of the work piece is cut by means of a cutter.

[0599] In one or more embodiments of the eleventh aspect, the seal material at the covering body workpiece may comprise or consist of a plurality of discretely arranged portions of seal material which are distributed across a surface of the workpiece, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a solidified seal material, wherein the solidified seal material of the obtained cover comprises at least one of said discretely arranged solidified portions of the seal material.

[0600] In one or more embodiments of the eleventh aspect, the solidified glass solder material of the obtained cover may comprises or consist of a continuous ring of glass solder material, such as a continuous, annular ring of glass solder material, or a ring where one or more predefined evacuation channels, such as discontinuations are formed in the seal material.

[0601] In one or more embodiments of the eleventh aspect, said working space is a vacuum chamber, and wherein the pressure is reduced in the vacuum chamber, such as by means of a pump, at least while said glass solder material is heated in the vacuum chamber. The inventors have found that manufacturing of a cover where the seal material is heated and softened provides an improved outgassing from the material and a more dense seal material. This may provide an improved cover that may provide an improved VIG unit gap sealing. Additionally or alternatively, it may allow for faster closure and seal of the pump out port in a VIG. The inventors have found that evacuation of the working space may help to provide an improved cover with an advantageous, solidified seal material.

[0602] In one or more embodiments of the eleventh aspect, the surface roughness of the surface of the solidified seal material which faces away from the covering body and / or workpiece may be above 10 pm, such as above 25 pm, such as above 35 pm. In one or more embodiments of the fifth aspect, the surface roughness of the surface of the solidified seal material which faces away from the covering body and / or workpiece may be between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 80 pm. In one or more embodiments of the fifth aspect, said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0603] This may e.g. enable an advantageous gas evacuation when the cover is used for sealing an evacuated VIG unit gap.

[0604] In one or more embodiments of the eleventh aspect, the surface roughness of the seal material surface is provided by means of protrusions at / in the surface of the seal material of the cover, wherein said protrusions are arranged staggered, such as substantially randomly, across the surface of the glass solder material.

[0605] In one or more embodiments of the fifth aspect, said surface roughness of the surface of the solidified seal material may be obtained as a result of said heating in the working space and the subsequent cooling of the seal material so as to solidify the seal material.

[0606] In one or more embodiments of the eleventh aspect, the covering body is made from metal or glass, such as annealed glass.

[0607] Annealed glass material may also be advantageous to work with compared to e.g. thermally tempered glass sheets when working with smaller parts. Annealed glass material can also resist a higher temperature for a longer time when compared to tempered glass sheets.

[0608] The present disclosure moreover relates, in a twelfth aspect, to a method of manufacturing one or more covers for use, such as subsequent use, during sealing of an evacuated gap of a vacuum insulated glass unit, wherein said method comprises:

[0609] - providing a covering body workpiece, wherein the covering body workpiece comprises a seal material, wherein the seal material is arranged at a surface of the covering body workpiece,

[0610] - obtaining a plurality of covers from the cooled covering body workpiece, such as by means of cutting, wherein each obtained cover comprises a portion of said seal material, such as a solidified seal material.

[0611] This may e.g. provide a more cost efficient and / or fast manufacturing method.

[0612] In some embodiments of the twelfth aspect, the seal material at the covering body workpiece comprises a glass solder material.

[0613] In some embodiments of the twelfth aspect, the seal material at the covering body workpiece is a solidified seal material.

[0614] In some embodiments of the twelfth aspect, the seal material at the covering body workpiece comprises a continuous layer of seal material, such as a continuous layer of the glass solder material, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a seal material originating from the continuous layer of seal material.

[0615] In some embodiments of the twelfth aspect, the seal material at the covering body workpiece comprises or consist of a plurality of discretely arranged portions of seal material which are distributed across a surface of the workpiece, and wherein a plurality of covers are obtained, such as cut, from the workpiece so that each of the obtained covers comprises a part of the covering body workpiece and a solidified seal material, wherein the solidified seal material of the cover comprises at least one of said discretely arranged solidified portions of the seal material. In some embodiments of the twelfth aspect, the seal material of the obtained cover comprises or consist of a continuous ring of seal material, such as glass solder material, such as a continuous, annular ring of glass solder material.

[0616] In some embodiments of the twelfth aspect, covers obtained comprises one or more features described in relation to one or more embodiments of the first, third, fourth or fifth aspect of the present disclosure. For example, one or more features relating to dimensions of the seal material, surface roughness of the seal material, the manufacturing in a working space and / or the like.

[0617] In some embodiments of the eleventh or twelfth aspect, the cover is manufactured by means of a method as previously described. In some embodiments of the eleventh or twelfth aspect, the cover is a cover according to one or more embodiments as previously described, such as according to one or more embodiments of the first aspect.

[0618] Description of drawings

[0619] The present disclosure will in the following be described in greater detail with reference to the accompanying drawings:

[0620] Fig. 1 illustrates a schematic view of a VIG unit assembly and a cover, according to various embodiments of the present disclosure,

[0621] Fig. 2 illustrates a schematic view of VIG unit manufacturing, according to various embodiments of the present disclosure,

[0622] Fig. 3 illustrates a schematic view of a VIG unit assembly and a cover, where the cover supports on a step surface, according to embodiments of the present disclosure,

[0623] Fig. 4 illustrates a schematic view of a cover comprising seal material and a surface roughness providing gas passages, according to embodiments of the present disclosure,

[0624] Figs. 4a-4b illustrates schematically a cover according to various embodiments of the present disclosure,

[0625] Fig. 5 illustrates schematically a VIG unit according to various embodiments of the present disclosure, Fig. 6 illustrates schematically a laminated VIG unit according to various embodiments of the present disclosure,

[0626] Fig. 7 illustrates schematically a laminated VIG unit according to various embodiments of the present disclosure, where a covering body projects through a plane comprising a major surface of a glass sheet, and projects into a lamination interlayer,

[0627] Fig. 8 illustrates schematically a laminated VIG unit according to various embodiments of the present disclosure, where a lamination layer extends into a larger diameter portion of a through hole,

[0628] Fig. 9 illustrates schematically a VIG unit according to various embodiments of the present disclosure,

[0629] Fig. 10 illustrates schematically a VIG unit according to various embodiments of the present disclosure, where a cover is placed on a major surface of a glass sheet so as to cover a single diameter through hole to seal an evacuated gap,

[0630] Fig. 10a illustrates schematically a laminated VIG unit according to various embodiments of the present disclosure, where a cover is placed on a major surface of a glass sheet, and where the cover is placed in a space between the major surface of the glass sheet and a lamination glass sheet,

[0631] Fig. 11 illustrates schematically manufacturing of a through hole, according to embodiments of the present disclosure,

[0632] Fig. 12 illustrates schematically a cross section of a surface roughness of a surface part of a VIG unit after permanent sealing of an evacuated gap, according to embodiments of the present disclosure,

[0633] Fig. 13 illustrates schematically manufacturing of a plurality of covers in a working space, according to embodiments of the present disclosure,

[0634] Fig. 14 illustrates schematically heating of covers during cover manufacturing, according to various embodiments of the present disclosure,

[0635] Fig. 15 illustrates schematically a flow chart relating to VIG unit manufacturing, according to embodiments of the present disclosure,

[0636] Fig. 16 illustrates schematically a flow chart relating to manufacturing of a cover for sealing an evacuated VIG unit gap, according to embodiments of the present disclosure, Fig. 17 Fig. illustrates schematically evacuation of a gap, where gas leaves through a gas passage, according to embodiments of the present disclosure,

[0637] Fig. 18 illustrates a grayscale image of a test example of a surface of a solidified seal material at a cover body surface, according to embodiments of the present disclosure,

[0638] Figs. 19A-

[0639] 19E illustrate grayscale images of a successful test of using a cover with the solidified seal material, according to embodiments of the present disclosure,

[0640] Figs. 20A-

[0641] 20B illustrate microscopic images of a test of a step surface, according to embodiments of the present disclosure,

[0642] Fig. 21 illustrates a microscopic image of a test sample comprising a glass sheet with a stepped through hole which is covered by a cover,

[0643] Fig. 22 illustrates a manufacturing of a vacuum insulated glass (VIG) unit, according to further embodiments of the present disclosure,

[0644] Fig. 22a illustrates a pushing body according to embodiments of the present disclosure,

[0645] Figs. 23A-

[0646] 23D illustrates various embodiments of a pushing body configured to be arranged between a glass sheet surface and a pushing part so as to push on a cover, according to various embodiments of the present disclosure, Figs. 24A and 25A illustrates various embodiments of the present disclosure wherein a workpiece comprising seal material for a plurality of covers is heated in a workspace, according to various embodiments of the present disclosure, Figs. 24B and 25B : illustrates obtaining a plurality of covers from a single workpiece, according to various embodiments of the present disclosure, Figs. 24C and 25C : illustrates covers obtained from a single workpiece, according to various embodiments of the present disclosure, Fig. 26 : illustrates a cover comprising a continuous layer of seal material, where the cover is used for sealing an evacuated gap, according to embodiments of the present disclosure,

[0647] Figs. 27A- 27B : illustrate a workpiece comprising a glass solder material perform, according to embodiments of the present disclosure,

[0648] 28 : illustrates a cover comprising solidified glass solder material, according to embodiments of the present disclosure,

[0649] 29 : illustrates a predefined evacuation channel having a minimum width, according to embodiments of the present disclosure,

[0650] 30 : illustrates a cover comprising solidified glass solder material, according to further embodiments of the present disclosure,

[0651] Fig. 31 : illustrates a measurement provided on solidified solder material obtained according to a method according to embodiments of the present disclosure,

[0652] Fig. 31a : illustrates solidified solder material obtained according to a method according to embodiments of the present disclosure,

[0653] Figs. 32-33 : illustrate schematically a cover supporting on a surface, according to various embodiments of the present disclosure,

[0654] Fig. 34 : illustrates schematically flow resistance areas during gap evacuation, according to embodiments of the present disclosure,

[0655] Fig. 35A-38 : illustrate schematically a VIG unit assembly comprising standoffs for cover support, according to various embodiments of the present disclosure,

[0656] Figs. 39A- 39B : illustrate schematically a floor surface around a through hole that is been shaped to have a wavy surface topology to obtain discrete standoff tops separated by valleys, according to embodiments of the present disclosure,

[0657] Fig. 40 : illustrates schematically a covering body workpiece comprising a preform comprising feet, according to embodiments of the present disclosure,

[0658] Figs. 41A- 41 C : illustrate schematically heating profiles for use during manufacturing of covers comprising a solidified glass solder material, according to various embodiments of the present disclosure,

[0659] Figs. 42A-45 : illustrate schematically embodiments of a covering body comprising protrusions and / or gaps in the circumference of the cover, according to various embodiments of the present disclosure,

[0660] Fig. 46 : illustrate schematically use of a shaping tool for shaping solidified solder material, according to embodiments of the present disclosure,

[0661] Fig. 47 illustrates a cover comprising solidified glass solder material comprising predefined evacuation channels, according to further embodiments of the present disclosure,

[0662] Figs. 48A-49 : illustrate schematically embodiments of a cover comprising a seal material comprising a primer and a solidified solder material, according to various embodiments of the present disclosure,

[0663] Figs. 50-51 D : illustrate schematically embodiments of a VIG unit assembly comprising a primer, according to various embodiments of the present disclosure,

[0664] Figs. 52 : illustrates schematically a laminated VIG unit comprising primers, according to various embodiments of the present disclosure, and

[0665] Fig. 53 : illustrates schematically a laser raster pattern, according to embodiments of the present disclosure.

[0666] Description

[0667] Fig. 1 illustrates schematically a vacuum insulated glass (VIG) unit assembly 1 according to embodiments of the present disclosure. The VIG unit assembly 1 comprises a first glass sheet 2 and a second glass sheet 3. In some embodiments, the first 2 and / or second glass sheet 3 may be a tempered glass sheet 2 such as a thermally tempered glass sheet. In other embodiments, the tempered glass sheets may be chemically tempered / hardened glass sheets. In still other embodiments, the glass sheet(s) 2, 3 may be non-tempered I un-tempered.

[0668] A plurality of support structures 5 a distributed in a gap 6 of the assembly 1. The gap 6 is arranged between a first major surface 2a of the first glass sheet 2 and first major surface 3a of the second glass sheet 3. In some embodiments, more than 300, such as more than 500, such as more than 1000, or even more than 2000 support structures may be distributed in the gap 6, e.g. in a predefined distribution pattern. The mutual distance between adjacent support structures 5 may be between 20 mm and 70 mm, such as between 30 mm and 50 mm, such as between 35 mm and 45 mm. This distance may be determined based on the glass sheet 2,3 type and / or thickness. For example, thermally tempered glass sheets are stronger and may allow for a larger distance between the support structures 5.

[0669] In some embodiments, the first glass sheet 2 and / or the second glass sheet 3 has / have a thickness TH1 between 2 mm and 5 mm, such as between 3 mm and 4 mm, such as between 3.5 mm and 4.5 mm (both endpoints included). The first 2 and second 3 glass sheets 2, 3 may in some embodiments have the same thickness TH1 or may in other embodiments be of different thickness TH1.

[0670] A peripheral edge seal 4 is configured to seal the gap 6. The edge seal 4 material may e.g. comprise metal solder or glass solder material such as glass frit based solder material, such as a low melting point solder glass material .

[0671] The distance between the surfaces 2a, 3a may in some embodiments be lower than 0.4 mm, such as lower than 0.3 mm, such as 0.2 mm or lower. The spacers / support structures are arranged to maintain the gap 6 when the gap 6 is evacuated. The spacers I support structures 5 may e.g. comprise glass material spacers, metal spacers and / or polymer spacers.

[0672] The first glass sheet 2 comprises a through hole 10. The through hole 10 extends between the first major surface 2a and a second, oppositely directed, major surface 2b of the first glass sheet 2. Thereby, gas 6 in the gap can be evacuated through the through hole 10.

[0673] In fig. 1 and several of the figures described further below, the through hole 10 is a stepped through hole. The stepped through hole 10 comprises a smaller diameter portion 10a and a larger diameter portion 10b. The larger diameter portion 10b is arranged proximate the second major surface 2b of the first glass sheet 2. The smaller diameter portion 10a is arranged proximate the first major surface 2a of the first glass sheet, and proximate the gap 6. A step surface 10s is arranged between the larger diameter portion 10b and the smaller diameter portion 10a.

[0674] The larger diameter portion 10b and the smaller diameter portion 10a may in embodiments of the precent disclosure be circular holes. The larger diameter portion 10b and the smaller diameter portion 10a may in embodiments of the precent disclosure be substantially concentric, annular holes.

[0675] A first wall surface 10x, such as an annular wall surface, encloses / encircles the smaller diameter portion 10a. This first wall surface 10x extends between the glass sheet surface 2a and the step surface 10s. A second wall surface 10z, such as an annular wall surface, encloses / encircles the larger diameter portion 10a. This second wall surface 19z extends between the step surface 10s and the glass sheet surface 2b. The step surface 10s extends between the wall surfaces 10x, 10z.

[0676] A cover 20 is provided. The cover 20 comprises a covering body 21 and a solidified seal material 22. The solidified seal material 22 comprises glass solder material which is attached to a surface 21a of the covering body 21. This may be provided during manufacturing of the cover. Various embodiments of the present disclosure relating to manufacturing the cover 20 are described further below. The glass solder material 22 may comprise or be a low melting point solder glass material.

[0677] In some embodiments, said providing of the cover 20 may comprise placing the cover 20 onto the first glass sheet 2 to cover the through hole. In some embodiments, said placing of the cover may comprise picking and placing or ejecting, such as dropping, said cover 20 comprising the covering body 21 and the solidified seal material 22 at the desired position at the first glass sheet to cover the through hole 10.

[0678] In some embodiments, said providing of the cover 20 may comprise a manufacturing of the cover 20 prior to placing the cover 20 at the first glass sheet 2 of the VIG unit assembly 1. Various embodiments of said manufacturing of the cover 20, according to embodiments of the present disclosure, are described in more details further below, e.g. in relation to figs. 13 and / or 14. The covering body comprises first and second surfaces 21a, 21b. These may be parallel. A side surface 21c extend between the first and second surfaces 21a, 21b. The covering body 21 may be made from e.g. metal or glass, such as annealed glass. The material of the covering body 21 may be selected based on the coefficient of thermal expansion of the covering body 21. In some embodiments, it may be preferred that the covering body 21 material has substantially the same coefficient of thermal expansion as the coefficient of thermal expansion of the first glass sheet 2. For example, the body 21 may be made from a glass material having a coefficient of thermal expansion substantially corresponding to the coefficient of thermal expansion of the first glass sheet 2.

[0679] The covering body 21 may comprise or consist of a structural body such as a structural glass body or a structural metal body.

[0680] The covering body may be disc shaped, polygonal shaped or the like. The outer boundary of the covering body 21 defined by the side surface 21c may or may not, in some embodiments of the present disclosure, be of substantially the same shape as the shape of the larger diameter portion 10b.

[0681] The cover 20 is arranged so that the solidified seal material 22 is placed between a surface part 2sp of the first glass sheet 2 and the covering body 21. The covering body

[0682] 21 hereby covers at least a part 10a of the through hole 10.

[0683] In fig. 1, The arranging of the cover 20 comprises arranging the solidified seal material

[0684] 22 opposite to, such as so as to support on, the step surface 10s (see also fig. 2). Thereby, the covering body 21 is arranged in the larger diameter portion 10b, covers the smaller diameter portion 10a, and overlaps the step surface 10s around the smaller diameter hole 10a. The side surface 10c is placed opposite to the side surface 10bs of the first glass sheet 2 which encloses the larger diameter portion 10b. The side surface 10bs of the first glass sheet 2 faces the side surface 21c of the covering body 21.

[0685] Fig. 2 illustrates schematically a manufacturing of a vacuum insulated glass (VIG) unit by means of a VIG unit assembly 1 , according to embodiments of the present disclosure. The VIG unit assembly 1 , such as a VIG unit assembly described above and / or below, is placed in a heating oven 70 chamber 71. The vacuum insulated glass VIG unit assembly 1 is then heated in the heating oven to a temperature above 200°C, such as above 280°C, such as above 320°C. In some embodiments, the peripheral edge seal 4 material is heated in the heating oven 70 to a temperature above the glass transition temperature of the peripheral edge seal 4 material.

[0686] The heating oven 70 may e.g. comprise a convection heating oven and / or a conduction heating oven. In some embodiments, this heating may be provided so as to soften the peripheral edge seal 4. After cooling of the heated and softened edge seal 4 material, the edge seal 4 will provide a hermetic, airtight edge seal 4 to seal the gap 6.

[0687] In some embodiments, radiation heating such as laser and / or infrared radiation may be used for heating and softening the edge seal material 4 material. This radiation heating may in some embodiments be provided in addition to heating by means of the furnace 70, or as an alternative to e.g. convection heating.

[0688] An evacuation cup 9 is arranged on the second surface 2b of the first glass sheet 2. In the illustrated example, this is provided while the VIG unit assembly is placed in the heating oven I furnace 70 chamber 71. The evacuation cup 9 covers the through hole 10 and is in tight contact with the surface 2b. In some embodiments, one or more gaskets (not illustrated, see fig. 22, ref. 9x), such as one or more graphite gaskets, may be used between the cup 9 housing 9a and the surface 2b so as to provide improved air tightness.

[0689] The interior cavity 9a of the cup 9 housing 9b is in fluid communication with a pump 30, e.g. through a piping 30. In some embodiments, the same pump 30 may be in fluid communication with a cup cavity 9a of a plurality of evacuation cups (not illustrated) by means of a piping system so as to provide simultaneous evacuation of a plurality of gaps of different VIG unit assemblies 1 arranged in the furnace 70 chamber 71.

[0690] The evacuation of the gap 6 by means of the pump 30 provides that gas GA, such as air, in the gap 6 is evacuated through the through hole 10 and out of the cup cavity through the piling 30a. The gap 6 evacuation by means of the pump 30 may in some embodiments be provided for at least 10 minutes, such as at least 20 minutes or at least 30 minutes before the evacuated gap 6 is sealed to provide a VIG unit.

[0691] As can be seen in fig. 2, the evacuation of the gap 6 by means of the pump 30 may in some embodiments of the present disclosure comprise that the gas GA evacuated from the gap 6 is evacuated through the through hole 10 and one or more gas passages 25 arranged between the surface part 2sp, 10s of the first glass sheet 2 and a surface 22a of the solidified seal material 22 which faces said surface part 2sp, 10s of the first glass sheet 2. Various embodiments hereof are described in more detail further below.

[0692] In some embodiments, the heating and softening of the peripheral edge seal 4 material may be provided while the evacuation cup 9 evacuates the gap 6, thereby providing a clamping of the peripheral edge seal 4 material by means of a pressure difference between the gap 6 and the exterior of the vacuum insulated glass unit assembly 1. This may help to squeeze and deform the peripheral edge seal material 4 when it has been sufficiently heated in the furnace chamber 71.

[0693] When the peripheral edge seal 4 is sufficiently cooled, and the gap 6 is sufficiently evacuated, such as to a reduced pressure below 10-2mbar, such as below 10-3mbar, the solidified seal material 22 of the cover 20 is heated by means of a heater 7 so as to soften the solidified seal material, thereby providing that the softened seal material 22 adhere to the surface part 2sp, 10s of the first glass sheet 2 around the through hole 10.

[0694] The heater 7 may in some embodiments comprise a radiation heater for providing a radiation heating beam 7a for heating the seal material 22 of the cover. In some embodiments, the radiation heater 7 may comprise or be a laser providing a laser beam 7a.

[0695] In some embodiments, the heating beam 7a may have a beam size that can cover and heat the entire surface seal material 22 of the cover 20 (that can be illuminated by the beam 7a) at once. In other embodiments, the heating beam 7a may comprise a laser beam 7a that is moved so as to revisit and heat the same area of the seal material 22 of the cover 20 a plurality of times, such as at least ten times, for example at least 40 times, such as at least 80 times, e.g. within 1 second, such as within 3 seconds or within 10 seconds to assure even seal material temperature increase.

[0696] In some embodiments, the covering body 21 may be heated by means of the heated seal material 22. Additionally or alternatively, in some embodiments, the covering body 21 may be configured to absorb energy from the heating beam 7a so as to heat the covering body 21. In some embodiments hereof, the covering body may comprise a layer of material or may comprise a material that is configured to absorb energy from the beam 7a so as to heat the covering body.

[0697] In fig. 2, the second glass sheet 3 is placed between the radiation heater 7 and the seal material 22 of the cover 20. The heater 7 is placed below the VIG unit assembly 1. Hereby, the seal material 22 of the cover 20 is heated by means of the heating beam which is radiated through the second glass sheet 3.

[0698] In some embodiments, the heating of the solidified seal material 22 of the cover 20 by means of the heater so as to soften the solidified seal material 22 may comprise heating the seal material 22 to a temperature above the rated glass transition temperature Tg of the seal material 22.

[0699] In some embodiments of the present disclosure, said heating by means of the heater 7 so as to soften the solidified seal material 22 may comprise heating the glass solder material 22 of the cover 20 to a temperature above the rated melting temperature Tm of the glass solder material 22.

[0700] When the seal material 22 has been sufficiently heated and is vetted to / bonds to also the surface 10s, 2sp of the first glass sheet 2 continuously around the smaller diameter portion 10a, A cooling the softened seal material 22 is provided so as to harden the softened seal material 22, thereby sealing the evacuated gap 6. The combination of the body 21 and the seal material 22 hence hermetically seals the through hole 10, thereby sealing the evacuated gap 6. The cooling of the seal material 22 may be provided by turning off the heating beam 7a which will cause the seal material 22 temperature to drop so that the seal material hardens / solidifies. The pump 30 may continue to provide pump out at least during the heating to soften the seal material 22 in order to be able to remove any gaseous species, if present, that may be released from the seal material 22 during the heating of the material. However, as explained in more details below, the seal material 22 and covering part 21 may have been subjected to a preheating and softening, and a subsequent cooling, before the cover 20 was placed to cover the through hole 10. This may result in a reduced amount of gaseous species being released during the heating by the heater 7 to seal the evacuated gap 6.

[0701] In some embodiments of the present disclosure, A clamping force / pushing force F1 may be provided by means of a clamping part 401 pushing part 40 so as to force the covering body 21 towards said surface part 2sp 10s of the first glass sheet 2. This force F1 may be provided before, during and / or after said heating of the solidified seal material 22 so as to soften the solidified seal material. In fig. 2, the clamping part 40 may comprise a spring such as a coil spring or another suitable type of spring. In other embodiments of the present disclosure, the clamping part / pushing part may comprise a weight using gravity to provide the force F1.

[0702] In fig. 2, the clamping part 40 is arranged inside the evacuation cup 9. The clamping part 40 may be attached to the housing 9b of the evacuation cup 9. The evacuation cup may provide a counter force so that the clamping part 40 can provide the force F1. If the clamping part 40 comprises a spring, the spring may be deformed between the cup housing 9b and cover 20 and hence provides the force F1.

[0703] During the evacuation of the gap 6 by means of the pump 30, the surface 22a of the solidified seal material 22 may support on, such as directly support on, the surface part 2sp, 10s of the first glass sheet 2. The surface 22a of the solder material 22 which faces the surface 2sp of the first glass sheet 2, such as the step surface 10s, may be pressed towards the surface 2sa of the first glass sheet 2, such as towards the step surface 10s by means of the clamping part 40. When the seal material 22 is sufficiently heated, the clamping part may push the covering body 21 to move the covering body further into the hole 11 and may e.g. help to deform the seal material 22 which has been softened by the heater 7.

[0704] The clamping force I pushing force F1 may also help to keep the cover 20 at a desired cover space 10b over the through hole 10a, 10, such as during said evacuation of the gap 6 and / or during moving of the VIG unit assembly 1. Further embodiments comprising using a clamping part / pushing part 40 are illustrated in figs. 22-23D, which are described in more details further below.

[0705] Figs. 3-3a illustrates schematically evacuation of the gap 6, where gas GA leaves through a gas passage between the seal material 22 surface 22a and the first glass sheet, according to embodiments of the present disclosure.

[0706] As mentioned above, the evacuation of the gap 6 by means of the pump 30 may in some embodiments of the present disclosure comprise that the gas GA evacuated from the gap 6 is evacuated through one or more gas passages 25 arranged between the surface part 2sp, 10s of the first glass sheet 2 and a surface 22a of the solidified seal material 22 which faces the surface part 2sp, 10s of the first glass sheet 2. In some embodiments.

[0707] In some embodiments of the present disclosure, at least 80%, such as at least 95%, such as at least 98%, of the evacuated gas GA from the gap 6 may be evacuated through said one or more gas passages 25.

[0708] In some embodiments of the present disclosure, the one or more gas passages 25 is / are provided as a consequence of a surface roughness of the surface 22a of the solidified seal material 22. Additionally or alternatively, said one or more gas passages 25 may be provided as a consequence of a surface roughness of said surface part 2sp of the first glass sheet 2, in this case the step surface 10s.

[0709] The surface roughness of the surface that the seal material 22 should bond to after heating of the seal material 22 of the cover 20 may be obtained as a consequence of drilling and / or laser cutting the through hole, such as the larger diameter portion 10b in the first glass sheet.

[0710] In some embodiments of the present disclosure, the surface roughness of the surface 22a of the solidified seal material 22 which faces the surface part 2sp, 10s of the first glass sheet 2 may be above 10 pm, such as above 25 pm, such as above 35 pm. This surface roughness may be the Ra surface roughness parameter or Rz surface roughness parameter, preferably the Ra surface roughness parameter. In some embodiments of the present disclosure, the surface roughness of the surface 22a of the solidified seal material 22 which faces said surface part 2sp, 10s of the first glass sheet 2 may be between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 75 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0711] The surface roughness may be defined along a sampling length corresponding to the full length, such as the diameter, of the solidified seal material at the top of the solidified seal material. This may in practice be defined along an envisaged circle which is concentric with the solidified solder material, and which has a diameter providing that the circle is arranged substantially midways between the outer and inner periphery of the solidified solder material. It is generally to be understood that surface roughness as mentioned in the present disclosure according to various embodiments of the present disclosure may e.g., be determined by means of a profilometer or a laser scanner. Surface roughness may be defined according to ISO 21920, such as ISO 21920-2.

[0712] The Ra surface roughness parameter may define, within a sampling length, the average roughness of the solidified seal material surface, e.g. including the deviations from the mean line.

[0713] The Rz surface roughness parameter may define the difference between the highest peak and lowest valley within the sampling length. It may define the maximum height of the profile.

[0714] In one or more embodiments of the present disclosure, the surface roughness of the surface part 2sp, 10s of the first glass sheet 2 which faces the solidified seal material 22 surface 22a may be above 10 pm, such as above 25 pm, such as above 35 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0715] In one or more embodiments of the present disclosure, the surface roughness of the surface part 2sp, 10s of the first glass sheet 2 which faces the solidified seal material 22 surface 2a may be between 10 pm and 150 pm such as between 25 pm and 100 m, such as between 35 pm and 80 pm. In one or more embodiments of the present disclosure, the surface roughness of the surface part 2sp, 10s of the first glass sheet 2 which faces the solidified seal material 22 surface 2a may be between 10 pm and 150 pm such as between 25 pm and 100 pm, such as between 45 pm and 80 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0716] In some embodiments of the present disclosure, the surface 22a roughness of the seal material 22 is larger than the surface roughness of the glass sheet surface 2b.

[0717] It is understood that in some embodiments, the surface roughness of the surface 22a of the solidified seal material 22 may be obtained during cover 20 manufacturing, as a result of a first pre-heating of the seal material 22 of the cover 20, and a subsequent pre-cooling of the softened seal material 22 so as to solidify the seal material 22. This pre-heating, such as pre-firing, of the seal material 22 may be provided prior to arranging the cover 20 at the VIG unit assembly. 11.

[0718] Said pre-heating of the seal material 22 may comprise heating the glass solder material 22 of the cover 20 to a temperature above the rated glass transition temperature Tg of the glass solder material 22. Embodiments of the manufacturing of the cover 20, according to embodiments of the present disclosure, are disclosed in more details further below.

[0719] Figs. 3 and 4 illustrates embodiments of the present disclosure, wherein the surface roughness of the solder material surface 22a is provided by means of protrusions at / in the surface of the glass solder material 22 of the cover 20. These protrusions may be arranged staggered, such as substantially randomly, across the surface of the glass solder material 22. Staggered protrusions of the solder material 22 and / or staggered protrusions of the surface 2sp, 10s of the first glass sheet may provide that the one or more gas passages 25 is / are non-straight. The protrusions may thus cause gas passages which deviates the gas GA flow of the evacuated gas from a straight line during gas evacuation through the one or more gas passages 25. The deviation of the gas passage 25 from a straight line may be deviations in a direction parallel to the first plane PL1 , and / or deviation in a direction perpendicular to the first plane PL1. The deviation of the gas passage 25 from a straight line may in some embodiments be deviations of the gas passage 25 from a straight, radial, envisaged line RL going through the center C of the covering body 21 and to the edge of the covering body 21, see example in fig. 4.

[0720] The staggered protrusions at the seal material surface 22a may be obtained by an initial heating of the seal material 22 during a first firing of the seal material 22 on the covering body 21 surface 21a during cover 20 manufacturing, where the seal material is heated to a temperature above a sintering temperature and in a time that provides that the seal material is fired to densify.

[0721] As illustrated in fig. 4, the solidified seal 22 material may encompass the through hole in an uninterrupted manner. As illustrated in fig. 4, the solidified seal material 22 may in embodiments of the present disclosure comprise or consist of a continuous ring of seal material 2, such as a continuous, annular ring of seal material. The width of the ring of seal material is larger than the size, such as diameter, of the hole 10, such as the smaller diameter portion 10a, that it is designed to surround.

[0722] The seal material 22 may thus be configured to extend continuously and uninterrupted so that no designed, predefined discontinuations are formed in the seal material.

[0723] The solidified seal material 22 may, prior to said heating of the solidified seal material 22 by means of said heater 7, be in continuous, un-interrupted contact with, and continuously adhere to, the covering body 21 surface 21a over the full length of the continuous ring of seal material 2.

[0724] The seal material 22 ring may e.g. have a circular, oval or polygonal (such as rectangular, hexagonal or the like) shape that is configured to surround a part of the through hole 10, 10a when the cover 20 is arranged on the first glass sheet 2 surface 10s, 2sp.

[0725] Figs. 4a-4b illustrate schematically, according to various embodiments of the present disclosure, a cover 20, such as the cover 20 of fig. 4, seen towards the major cover body surface 21a (fig. 4a) and towards the side surface (fig. 4b) respectively, of the covering body 21. The solidified seal material 22 has a height H22, see fig. 4a. The height H22, such as the average height, of the seal material 22 may in some embodiments be less than 0.6 mm, such as less than 0.4 mm, such as less than 0.3 mm. The height H22, such as the average height, of the seal material 22 may in some embodiments be larger than 0.3 mm, such as larger than 0.5 mm, such as larger than 0.6 mm.

[0726] The heigh H22, such as local maximum height, of the solidified seal material 22 may in some embodiments vary less than 0.2 mm, such as less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm over the entire longitudinal extent 22e of the seal material 22 of the cover 20.

[0727] The heigh H22, such as local maximum height, of the solidified seal material 22 may in some embodiments vary less than 0.02 mm, such as less than 0.01 mm, such as less than 0.005 mm, over the entire longitudinal extent 22e of the seal material 22 of the cover 20.

[0728] Fig. 5 illustrates schematically a VIG unit 100 according to embodiments of the present disclosure, after the evacuated gap 6 has been sealed by means of the cover 20. The seal material 22 is placed between the surface 21a of the covering body 21 and the step surface 10s. The seal material 22 provides a hermetic seal between the first glass sheet 2 and the covering body. The surface 21 b of the covering body 21 that faces away from the evacuated gap 6 may be substantially flush with the second surface 2b of the first glass sheet 2.

[0729] Fig. 6 illustrates a laminated VIG unit 100 according to embodiments of the present disclosure. Here, a lamination glass sheet 8 is attached to the second major surface 2b of the first glass sheet 2 by means of a lamination interlayer 8a so that the lamination glass sheet 8 extends over and covers the cover 20 and the through hole 10. The lamination interlayer 8a may also, as illustrated, extend so as to cover the covering boy 21.

[0730] The lamination of the VIG unit 100 may be obtained by means of a combination of pressing and heating the VIG unit 100, the lamination glass 3 and the interlayer 8a so that the interlayer 8a softens and thereby adhere to major surfaces 8s, 2b of the glass sheets 8, 2.

[0731] The lamination interlayer 8a may comprise or be one or more of the following::

[0732] • ethylene vinyl acetate (EVA),

[0733] • polyisobutylene (PIB),

[0734] • polyacetals such as polyvinyl butyral (PVB),

[0735] • transparent polyurethane (Pll),

[0736] • thermoplastic polyurethane (TPU),

[0737] • polyvinyl chloride (PVC),

[0738] • polyesters,

[0739] • cyclo olefin polymers (COP),

[0740] • ionomers and / or an adhesive configured to be activated by ultraviolet radiation.

[0741] PVB, EVA or TPU may however be preferred as the lamination interlayer 8.

[0742] The lamination interlayer 8a may in some embodiments have an average thickness of at least 0.4 mm, such as at least 0.6 mm, such as at least 0.7 mm.

[0743] The lamination interlayer 8a may in some embodiments have an average thickness between 0.4 mm and 1.8 mm, such as between least 0.5 mm and 1.2 mm, such as between 0.7 mm and 1 mm. The lamination interlayer 8a may in certain embodiments have an average thickness between 0.4 mm and 2 mm.

[0744] The lamination interlayer 8a may or may not be of the sound attenuating type. Sound attenuating lamination sheets may comprise three or more layers / sheets stacked on top of each other, where one intermediate layer has a glass transition temperature that is lower than the neighboring, such as adjacent, layers. In other embodiments, the lamination layer may comprise a single sheet of material, or e.g. a plurality of stacked sheets of the same material.

[0745] It is generally understood that in some embodiments of the present disclosure, the lamination interlayer 8a may adhere to the cover 20 such as to the covering body 21 surface 21b. In fig. 6, the surface 21b of the covering body 21 that faces away from the evacuated gap 6 is substantially flush with the second surface 2b of the first glass sheet 2.

[0746] Fig. 7 illustrates schematically a VIG unit 100 according to embodiments of the present disclosure, wherein the covering body 21 extends through a plane PL1 comprising the second major surface 2b of the first glass sheet 2. The surface 2b of the cover is arranged below the surface 8s of the lamination glass sheet 8 to which the interlayer 8a adheres. The lamination interlayer 8a may hence extend around the covering body 21 and e.g. also in between the covering body 21 surface 21b and the lamination glass sheet 8 surface 8s.

[0747] Fig. 8 illustrates schematically a VIG unit 100 according to embodiments of the present disclosure, wherein the surface 21 b of the covering body 21 , which faces away from the gap 6 and the seal material 22 of the cover 20, is arranged below the second surface 2b of the first glass sheet 2 after said cooling of the softened seal material 22 so as to seal the evacuated gap 6. Fig. 8 moreover illustrates a further embodiment wherein a lamination interlayer 8a material extend into the through hole 10. The lamination interlayer 8a material may in some embodiments adhere to the surface 21b of the cover 20 which faces away from the gap 6.

[0748] At the final vacuum insulated glass unit 100, the surface 21b of the cover 20, such as of the covering body 21 , which faces away from the gap 6 may be configured to be arranged less than 2 mm, such as less than 1 mm, such as less than 0.6 mm, for example less than 0.4 mm from the plane PL1 comprising the second major surface 2b of the first glass sheet 2. The surface 21b may be above (fig. 7) or below (fig. 8) the second major glass sheet 2 surface 2b, or may be flush with the surface 2b.

[0749] In some embodiments, not illustrated, a resin may be placed between the lamination layer and the surface 21b of the covering body. In some embodiments, not illustrated, a resin may be placed between the lamination layer and the surface 21b of the covering body so as to extend into the larger diameter portion 10b.

[0750] Fig. 9 illustrates schematically a cross section of a VIG unit 100 according to various embodiments of the present disclosure. As also disclosed above, the through hole 10 is in fig. 9 a stepped through hole. The stepped through hole 10 comprises the smaller diameter portion 10a and the larger diameter portion 10b. The larger diameter portion 10b is arranged proximate the second major surface 2b of the first glass sheet 2. The smaller diameter portion 10a is arranged proximate the first major surface 2a of the first glass sheet, and proximate the gap 6. The larger diameter portion 10b has a first diameter D1 , and the smaller diameter portion 10a has a second diameter D2.

[0751] In one or more embodiments of the present disclosure, the diameter D1 of the larger diameter portion 10b is at least 2 mm, such as at least 3 mm, larger than the diameter D2 of the smaller diameter portion 10a.

[0752] In one or more embodiments of the present disclosure, the diameter D1 of the larger diameter portion 10b may be between 5 mm and 12 mm, such as between 6 mm and 9 mm. In some embodiments, the diameter D1 of the larger diameter portion 10b may be between 3 mm and 7 mm, such as between 4 mm and 6 mm.

[0753] In some embodiments of the present disclosure, the diameter D2 of the smaller diameter portion 10a may be at least 1 mm, such as at least 2 mm, such as at least 3 mm. In some embodiments of the present disclosure, the diameter D2 of the smaller diameter portion 10a may be less than 5 mm, such as less than 4 mm, such as less than 3 mm or less than 2 mm.

[0754] In some embodiments of the present disclosure, the diameter D2 of the smaller diameter portion 10a may be between 1 mm and 4 mm, such as between 1 mm and 3 mm.

[0755] The width, such as the diameter D3 of the covering body 21 is smaller than the diameter D1 of the larger diameter portion 10b. In some embodiments, the difference in diameter D1-D3 between the diameter D3 of the covering body 21 and the diameter D1 of the larger diameter portion 10b may be less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

[0756] In one or more embodiments of the present disclosure, the thickness H2 of the covering body 21 may be 2.5 mm or less, such as 1.5 mm or less, In one or more embodiments of the present disclosure, the thickness of the covering body 21 may be between 0.7 mm and 2.9 mm, such as between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm, endpoints included.

[0757] In one or more embodiments of the present disclosure, the depth DE1, such as the maximum depth, of the larger diameter portion 10b may extend over less than 70%, such as over less than 60%, such as over less than 50%, of the thickness TH1 of the first glass sheet 2.

[0758] In one or more embodiments of the present disclosure, the depth DE1 of the larger diameter portion 10b may be between 20% and 70%, such as between 30% and 60%, such as between 40% and 50%, of the thickness TH1 of the first glass sheet 2.

[0759] In one or more embodiments of the present disclosure, the depth DE1 of the larger diameter portion 10b is between 1 mm and 4 mm, such as between 1.5 mm and 3 mm, such as between 1.9 mm and 2.5 mm.

[0760] In one or more embodiments of the present disclosure, the depth DE1, such as the maximum depth, of the larger diameter portion 10b is between 0.05 mm and 0.35 mm larger, such as between 0.15 and 0.25 mm, larger than the thickness H2, such as the maximum thickness, of the covering body 21.

[0761] In other embodiments of the present disclosure, the depth DE1 , such as the maximum depth, of the larger diameter portion 10b may be smaller than the thickness H2, such as the maximum thickness, of the covering body 21.

[0762] In some embodiments of the present disclosure, the maximum thickness H3 of the seal material 22 arranged between the covering body 21 surface 21a and the surface part 10s of the first glass sheet 2 which faces said surface 21a, after said sealing of the gap 6, may be between 0.050 mm and 0.4 mm, such as between 0.075 mm and 0.3 mm, such as between 0.125 mm and 0.250 mm. The first glass sheet 2 and / or the second glass sheet 3 may in embodiments of the present disclosure have a thickness TH1 between 2 mm and 5 mm, such as between 3 mm and 4 mm, both endpoints included.

[0763] The first glass sheet 2 and the second glass sheet 3 may have the same or different thickness TH1.

[0764] The thickness H2 of the covering body 21 may in some embodiments be at least 30% lower, such as at least 50% lower, or at least 60% lower, than the thickness TH1 of the first glass sheet 2.

[0765] The thickness of the covering body 21 may in some embodiments of the present disclosure be between 30% and 85% lower, such as between 40% and 60% lower, such as between 45% and 55% lower, than the thickness TH1 of the first glass sheet 2.

[0766] The thickness H2 of the covering body 21 may in some embodiments be lower than the depth DE1 of the larger diameter portion 10b. In some embodiments, the thickness H2 of the covering body 21 may be at least 5% lower or at least 10% lower, than the depth DE1 of the larger diameter portion 10b.

[0767] In some embodiments of the present disclosure, the thickness H2 of the covering body 21 may be between 3% and 30% lower, such as between 5% and 20% lower , such as between 8% and 15% lower than the depth DE1 of the larger diameter portion 10b.

[0768] In some embodiments of the present disclosure, the thickness of the covering body 21 may be between 30% and 85% lower, such as between 40% and 60% lower, such as between 45% and 55% lower, than the thickness TH1 of the first glass sheet 2.

[0769] It is generally understood, as illustrated in fig. 9 and several figures described above, that the step surface 10a may be shaped so as to extend in a direction that is substantially parallel with a plane PL1 defined by / comprising a major surface 2a of the first glass sheet 2. In fig. 9, said plane PL1 comprises the second, major glass sheet surface 2b of the first glass sheet. In other embodiments of the present disclosure, the step surface 10a may be shaped to incline with a predefined angle to the plane PL1, such as an obtuse angle or an acute angle to the plane PL1. Fig. 9 illustrates a still further embodiment of the present disclosure. Here, the previously mentioned clamping force F1 has directly or indirectly pushed the covering body 21 so as to deform the heated and softened seal material 22. This has provided that a part of the softened seal material 22 has moved (see dashed arrow) in between a side surface 21c of the covering body 21 and a side surface 10bs of the first glass sheet 2 which faces the side surface 21c of the covering body 21. The side surface 21c of the covering body 21 extends between the surfaces, such as major surfaces, 21a, 21b of the covering body 21.

[0770] The seal material 22 may hence adhere to both the surfaces 21a, 10s, and moreover to the surfaces 21c, 10bs.

[0771] Figs. 10 and 10a illustrates schematically a cross section of embodiments of the present disclosure, wherein the through hole 10 is a single diameter hole, and thus not a stepped hole. The diameter of the hole 10 may be between 1 mm and 5 mm, such as between 1 mm and 3 mm.

[0772] The cover 20 comprises the covering body 21. The covering body may be made from a thin sheet of material, such as a metal, or glass. The solidified seal material supports on the major, second surface 2b of the first glass sheet. Evacuation of the gap 6 may e.g. have been provided as previously described according to various embodiments of the present disclosure.

[0773] The combined height / thickness H2 of the covering body 21 and the height H3 of the seal material 22 (after evacuation and sealing of the gap 6) may e.g. In some embodiments be less than 2 mm, such as less than 1 mm, such as less than 0.75 mm.

[0774] In fig. 10 and 10a, the combined height / thickness of the covering body 21 and the seal material 22 (after evacuation and sealing of the gap 6) may be less than 2 mm, such as less than 1 mm, such as less than 0.75 mm.

[0775] Fig. 10a illustrates a laminated version of the embodiment illustrated in fig. 10. Here, the lamination glass 8 covers the cover 20. The combined height / thickness of the covering body 21 and the seal material 22 is here lower than the thickness of the lamination interlayer 8a.

[0776] The lamination interlayer 8a may in some embodiments have an average thickness of at least 0.4 mm, such as at least 0.6 mm, such as at least 0.7 mm.

[0777] The lamination interlayer 8a may in some embodiments have an average thickness between 0.4 mm and 2 mm, such as between 0.5 mm and 1.2 mm, such as between 0.7 mm and 1 mm.

[0778] The lamination interlayer 8a may in some embodiments have an average thickness between 0.7 mm and 2 mm, such as between 0.7 mm and 1.7 mm.

[0779] It is generally understood that the lamination interlayer 8a may adhere to the major surface 21b of the covering body 21, or in other embodiments may not adhere to the major surface 21 b of the covering body 21.

[0780] Fig. 11 illustrates an embodiment of the present disclosure, wherein the through hole 10 in the first glass sheet 2 is provided. This providing of the through hole comprises laser cutting the through hole in the first glass sheet 2 by means of a laser 90 beam 90a. The laser cutting is conducted prior to assembling of the vacuum insulated glass VIG unit assembly 1 as described above. If the first and second glass sheets 2 are tempered glass sheets, such as a thermally tempered glass sheet, and said laser cutting by means of the laser 90 may be provided prior to tempering of the first glass sheet 2.

[0781] In one or more embodiments of the present disclosure, the surface roughness of the final surface 10s of the first glass sheet 2 which will in the end face the solidified seal material 22 surface 22a may be above 10 pm, such as above 25 pm, such as above 35 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0782] In one or more embodiments of the present disclosure, the surface roughness of the surface part 2sp, 10s of the first glass sheet 2 which faces the surface 2a of the solidified seal material 22 may be between 10 urn, and 150 pm such as between 25 pm and 100 m, such as between 35 pm and 75 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0783] See also the previous description relating to surface roughness of the first glass sheet 2 surface and the seal material 22 surface 22a roughness.

[0784] The dash-dotted line 91 indicates the final surface level of the stepped surface 10s when the laser 90 has finished. In some embodiments, the laser 90 may provide the entire, stepped through hole 10. In other embodiments, a mechanical drilling may provide an initial through hole having the diameter of the smaller diameter portion 10a, and the laser 90 may then provide the remaining larger diameter portion 10b around that initial through hole to provide the larger diameter portion having the desired depth DE1.

[0785] Fig. 12 illustrates schematically a cross section of an embodiment of the present disclosure, wherein the surface roughness of the surface part 10s, 2sp is illustrated after the evacuated gap has been permanently sealed by the cover 20.

[0786] As can be seen, the surface roughness of the surface of the first glass sheet. Such as the step surface 10s, of the first glass sheet 2 may remain whereas the material of the seal 22 of the cover has now adapted to the surface roughness of the step surface 10s. The surface roughness value of the surface 21a of the cover 21 to which the seal material 22 bonds / adheres may be significantly lower, such as at least 5 times lower or 10 times lower, or even 50 times lower than the surface roughness value, such as an Ra value, of the glass sheet surface 10s.

[0787] In one or more embodiments of the present disclosure, the cover 20, prior to arranging of the cover at the VIG unit assembly, may have been subjected to a heating of the seal material 22 on the covering body 21 surface 21a so as to soften, such as liquify, the seal material, and so as to obtain adherence to the covering body 21 surface 21a. Subsequently, the softened glass solder material is cooled so as to solidify the glass solder material. The resulting cover 21 with the solidified seal material 22 is then used at the VIG unit assembly 1 for the final, permanent seal of the evacuated gap 6, e.g. as described above according to various embodiments of the present disclosure. Fig. 13 illustrates schematically manufacturing of a plurality of covers 20 for use at a VIG unit assembly, according to embodiments of the present disclosure.

[0788] The manufacturing of the cover 20 may in some embodiments comprise initially providing one or more covering body workpieces 21 , such as covering body discs.

[0789] Then, a glass solder material 22 is applied to a surface 21a of each of the provided plurality of covering body workpieces 21. The applied glass solder material 22 is a seal material. The applied seal material may e.g. have been mixed with a solvent so as to provide a paste-like texture of the applied solder material. An outlet, such as a nozzle, may be used for applying the seal material 22.

[0790] The softening temperature of the covering body workpiece 21 is larger than a softening temperature of the applied glass solder material 22. Hence, the glass solder material 22 may be fired to soften and melt without this affecting the structure of the workpiece 21. The workpiece may comprise or consist of a glass material body, such as an annealed glass body, or a metal material body.

[0791] The covering body workpieces 21 with the applied glass solder material 22 thereon are then arranged in working space 50. In some embodiments, the working space may be a vacuum chamber. The working space, such as the vacuum chamber 50, may be enclosed by walls 55.

[0792] The manufacturing of the cover 20 comprises in fig. 13 initially providing a plurality of covering body workpieces 21, such as covering body discs. A plurality of covers 20 are obtained from the cooled covering body workpieces after the heating in the working space 50. Each of the covers may be used individually as a cover 20. At least 5 individual workpieces, such as at least 20 individual workpieces, at least 50 individual workpieces or at least 100 individual workpieces, such as at least 500 individual workpieces, with seal material thereon may be arranged in the working chamber at once. In some embodiments, the manufacturing of the covers may be a batch process.

[0793] The pressure in the vacuum chamber 50 is then reduced, such as by means of a pump 80 which evacuates gas through an outlet 51 of the vacuum chamber 50. Thereafter, the applied glass solder material 22 is heated in the vacuum chamber 50 by means of a heater 60 while said pressure in the vacuum chamber 50 is remained reduced. The reduction in pressure may alternatively be started after the heating of the seal material 22 is started.

[0794] The heating / firing of the seal material 22 by means of the heater 60 is provided so as to soften, such as liquify, the applied glass solder material 22 so as to provide an outgassing of the applied glass solder material.

[0795] The reduced pressure in the chamber 50 may help to provide a more dense seal material 22 at the end of the heating, after the seal material 22 has solidified on the covering body 21 surface 21a.

[0796] When the seal material 22 has been sufficiently heated and softened, the heated covering body workpieces 21 with the outgassed glass solder material 22 thereon are cooled so as to solidify the glass solder material 22.

[0797] Finally, the pressure in the vacuum chamber 50 is equalized and the covers can then be removed from the vacuum chamber and used at a VIG unit assembly 1 for covering a through hole to seal an evacuated gap 6.

[0798] Said equalizing of the pressure in the vacuum chamber 50 may e.g. be provided during or after the cooling of the seal material 22 and covering body 21 in the vacuum chamber 50. In other embodiments, the equalization of the pressure in the vacuum chamber 50 may e.g. be provided during a part of, such as within the last 50%, such as within the last 20%, such as within the last 5%, of the seal material 22 heating time (see e.g. ref. Ht21 of fig. 14).

[0799] The heating of the applied glass solder material 22 by means of the heater 60 may be provided so as to soften, such as liquify the applied glass solder material 22. In some embodiments, solvent may be outgassed from the seal material by the heater before the seal material start to soften.

[0800] In one or more embodiments of the present disclosure, the heating of the applied seal material 22 so as to e.g. soften and / or outgas the seal material at the respective covering body 21 may comprise heating the seal material to a temperature above 200°C, such as above 300°C, such as above 350°C.

[0801] In one or more embodiments of the present disclosure, the heating of the applied seal material 22 so as to soften the seal material at the respective covering body 21 may comprises heating to a temperature between 200°C and 450°C, such as between 300°C and 400°C, such as between 320°C and 370°C.

[0802] In one or more embodiments of the present disclosure, said heating by means of the heater 60 comprises heating the glass solder material 22 of the cover 20 to a temperature above the rated glass transition temperature Tg of the glass solder material 22.

[0803] In some embodiments of the present disclosure, said heating by means of the heater 60 may comprise heating the glass solder material 22 of the cover 20 to a temperature above the rated melting temperature Tm of the glass solder material 22.

[0804] In one or more embodiments of the present disclosure, said reducing of the pressure in the vacuum chamber 50 comprises reducing the pressure in the vacuum chamber to a pressure below 1 bar, such as below 500 mbar, such as below 100 mbar, such as below 20 mbar, such as to 10 mbar or below.

[0805] In one or more embodiments of the present disclosure, said reducing of the pressure in the vacuum chamber 50 comprises reducing the pressure in the vacuum chamber 50 to a pressure between 10 “3millibar and 500 mbar, such as between 10 “2millibar and 100 mbar.

[0806] In one or more embodiments of the present disclosure, said reducing of the pressure in the vacuum chamber 50 comprises reducing the pressure in the vacuum chamber 50 to be above 10 “3millibar, such as above 10 “2millibar.

[0807] The plurality of covering bodies 21 may be placed on a base 95 in the vacuum chamber 50.

[0808] In some embodiments, the heater 60 comprises a radiation heater, such as a laser. In other embodiments, the heater 60 comprises a conduction heater. In this case, the covering bodies 21 may be placed on a base 95, such as a support base plate, which is heated by the heater 60. The surface 21a of the covering body 21 with the applied seal material faces away from the base 95. This heats the covering bodies 21 , and the covering bodies 21 then heats the seal material 22 so as to provide the softening of the seal material 22. The seal material 22 is thus in this embodiment heated by the covering body 21. The base 95 may also be referred to as a conduction heating part.

[0809] It is understood that in some embodiments, convection heating may be used in the vacuum chamber 50, e.g. while the chamber is evacuated and the seal material outgasses, dependent on the amount of evacuation provided.

[0810] In some embodiments, the heater 60 may comprise a convection heater and / or a conduction heater. It is also understood that the heater 60 in some embodiments may or may not comprise a combination of different heaters.

[0811] In some embodiments, a heater 60 may provide convection heating for heating the conduction heating part 95, such as a base. The conduction heating part 95 may then transfer the heat energy to the covering body / bodies that may be directly or indirectly in contact with the conduction heating part 95.

[0812] It is understood that convection heating may additionally or alternatively also be used for directly heating the covering bodies 21 and the seal material 22. The ambient, remaining gas / air in the chamber 50 hence heats the covering bodies 21 and the seal material 22 by means of convection heating. This gas / air may be circulated by the heater 60.

[0813] The heating of the seal material 22 by means of the heater 60 in the vacuum chamber 50 may be provided relatively slowly so as to accommodate extraction / release of solvent and binder from the seal material while maintaining an open structure in the seal material.

[0814] It is understood that in other embodiments, the pressure in the chamber 50 may be between 500 mbar and 1 bar during the heating of the seal material, such as over at least 20%, 40% or at least 90% of the heating time. In still further embodiments, the vacuum chamber may be omitted and the seal material may be heated and softened by a heater 60 at e.g. atmospheric pressure. In that case, convection and / or conduction heating may be used.

[0815] In fig. 13, a plurality of individual covering body workpieces 21 are heated in the workspace I working space 50. Each individual covering body workpiece comprises a portion of the seal material to be heated. The individual covering body workpieces 21 are each configured to constitute a cover 20, such as a single cover, when the seal material has been solidified. In some embodiments, the covers 20 may substantially not need any further treatment after the cooling, and a cover 20 may thus be obtained directly from the respective cooled workpiece with solidified seal material 22 thereon. In other embodiments, a plurality of covers may be obtained from a single workpiece after the seal material has been solidified. Embodiments hereof are described in more details further below, see e.g. figs. 24A-25C.

[0816] Fig. 14 illustrates schematically a controlled heat increase rate for heating the seal material 22 at the covering bodies 21 , according to embodiments of the present disclosure. The graph T21 illustrates the temperature of the seal material 22 during the heating provided so as to soften the seal material during the manufacturing of the cover, prior to using the cover at the VIG unit assembly 1. The dash dotted line Tar21 illustrates the desired target temperature of the seal material 22 at the covering body 21.

[0817] The target temperature Tar21 may in embodiments be set to a temperature at or above the rated glass transition temperature Tg of the glass solder material 22.

[0818] The target temperature Tar21 may be a temperature setting at a temperature above 200°C, such as above 300°C, such as above 350°C. In some embodiments, the target temperature Tar21 may be set to a temperature between 200°C and 450°C, such as between 300°C and 400°C, such as between 320°C and 370°C or between 350°C and 390°C.

[0819] In some embodiments, the heating of the seal material 21 may be provided with a heat increase rate of less than 5 °C / minute, such as less than 2 °C / minute, such as less than 1 °C / minute or less than 0.7 °C / minute. In some embodiments, the heating of the seal material may be provided with a heat increase rate of substantially 0.5 °C / minute.

[0820] In some embodiments, the heating of the seal material 21 may be provided with a heat increase rate of at least than 0.1 °C / minute, such as at least 0.3 °C / minute, such as at least 0.4 °C / minute.

[0821] In some embodiments, the heating of the seal material 21 may be provided with a heat increase rate of between 0.1 °C / minute and 5 °C / minute, such as between 0.1 °C / minute and 2 °C / minute, such as between 0.3 °C / minute and 0.7 °C / minute.

[0822] This heat increase rate may in some embodiments of the present disclosure be conducted over at least 40%, such as over at least 50%, such as over at least 70% or over at least 95% of the total heating time Ht21. In some embodiments, the heat increase rate may be conducted / provided over substantially 100% of the heating time Ht21.

[0823] This heat increase rate may in some embodiments of the present disclosure be conducted over at least 20% of the total heating time Ht21.

[0824] In some embodiments, the heat increase rate of the seal material 22 may be provided over the first 50%, such as the first 70% or the first 95% of the total heating time.

[0825] In other embodiments, said heat increase rate is provided at least over the last 50%, such as the last 70% or the last 95% of said heating time.

[0826] The heating time HT21 where the seal material 22 temperature T21 is controlled to be gradually increased is in fig. 14 defined between the initiation time Tinit of the seal material heating and to the time Tend where the seal material 22 has reached the desired seal material target temperature Tar21. In some embodiments, the seal material 22 may be maintained at the target temperature Tar21 for a predefined time period (between Tend and Tc) before initiating the cooling of the seal material 22 at time Tc. In other embodiments, the cooling of the seal material 22 may be initiated substantially at time Tend when the target temperature Tar21 has been reached. In some embodiments, the heater 60 may heat the entire seal material 22, such as the full mass of the seal material 22 on the covering body surface 21 to the target temperature Tar21. This may soften the remaining material after outgassing.

[0827] In some embodiments, The heater 60 may heat the seal material 22 to a target temperature which is within ±30°C, such as within ±20°C, such as within ±10°C from the temperature to which it 22 is heated by means of the heater 7 (see fig. 2) when reheating and re-softening of the seal material 22 to seal the evacuated gap 6.

[0828] In some embodiments of the present disclosure, the heat increase rate of the seal material (between time Tinit and time Tend) may be provided over at least 50%, such as at least 70%, such as at least 95%, of the total heating time of the seal material 22 during cover manufacturing.

[0829] In some embodiments, the heating time Ht21 before the seal material 22 reaches the target temperature Tar21 may be at least 1 hour, such as at least 3 hours, such as at least 5 hours, such as at least 8 hours.

[0830] In some embodiments, the heating time Ht21 before the seal material 22 reaches the target temperature Tar21 may be at least 20 minutes such as at least 40 minutes.

[0831] In some embodiments of the present disclosure, the heating time Ht21 before the seal material reaches the target temperature is at least 30 minutes, such as at least 1 hour.

[0832] In some embodiments of the present disclosure, the heating time Ht21 before the seal material reaches the target temperature is between 30 minutes and 14 hours, such as between 1 hour 10 hours, such as between 3 hours and 9 hours.

[0833] In some embodiments, the heat increase rate of the seal material 22 may be controlled to vary over the heating time Ht21. In other embodiments, the heat increase rate of the seal material 22 may be controlled to be substantially constant over the heating time Ht21.

[0834] The heating of the seal material 22 in the working space 50 may be considered a first pre-heating and softening, such as liquification, of the seal material 22. When the cover 20 comprising the solidified seal material is then used for permanently sealing the evacuated gap 6 of the VIG unit as e.g. described previously, such as in the furnace 70, the seal material 22 is re-heated and resoftened.

[0835] The seal material, 22 when applied to the covering body, may in embodiments of the present disclosure comprise glass frit material, filler material and binder material. In some embodiments, solvent material may also be present. The applied seal material 22 may comprise or be a low melting point solder glass material.

[0836] The heating of the seal material 22 in by means of the heater 60 during cover 20 manufacturing may burn out I remove binder material and / or solvent material in the seal material 22.

[0837] In some embodiments, the amount of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may be below 5 wt%, such as below 2 wt%, such as below 1 wt%.

[0838] In some embodiments, the amount of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may be above 0.1 wt%, such as above 0.4 wt%, such as above 1 wt%.

[0839] In some embodiments, the amount of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, is at least 1 %, such as at least 5 %, such as at least 10%, compared to the amount of binder material in the seal material 22 before said heating by means of the heater 60.

[0840] In some embodiments, the amount of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may be between 0.1 wt% and 5 wt%, such as between 0.4 wt% and 2 wt%.

[0841] In some embodiments, the amount of solvent material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may be below 4 wt%, such as below 2 wt%, such as below 1 wt% or below 0.1 wt%. In some embodiments, said heating by means of the heater 60 may reduce the amount of binder material in the seal material by at least 10 %, such as by at least 50 %, such as by at least wt% when compared to the amount of binder material in the seal material 22 before said heating by means of the heater.

[0842] In some embodiments, the heating by means of said heater 60 may reduce the amount of solvent material in the seal material 22 by at least 40 %, such as at least 80 %, such as at least wt% when compared to the amount of solvent material in the seal material before said heating by means of the heater 60.

[0843] In some embodiments, the amount of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may have been reduced by at least 60%, such as at least 80%, such as at least 95% when compared to the amount (wt%) of binder material in the seal material 22 arranged at the covering body 21 surface before it is heated by the heater 60 to the target temperature Tar21.

[0844] In some embodiments, the amount of solvent material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22, may have been reduced by at least 60%, such as at least 80%, such as at least 98%, when compared to the amount (wt%) of solvent material 22 at the covering body 21 before it is heated by the heater 60 to the target temperature Tar21.

[0845] In some embodiments, the amount (wt%) of binder material in the seal material 22 before it has been heated by the heater 60 and solidified by cooling it 22 may be higher than the amount (wt%) of binder material in the seal material 22 after it has been heated by the heater 60 and solidified by cooling it 22.

[0846] In some embodiments, the amount (wt%) of binder material in the seal material 22 before it has been heated by the heater 70 and solidified by cooling it 22 to seal the hole 10 and thereby seal the evacuated gap may be higher than the amount (wt%) of binder material in the seal material 22 after it has been heated by the heater 70 and solidified by cooling it 22 to seal the evacuated gap.

[0847] As an example, if the amount of binder in the seal material before the heating to soften the seal material is e.g. 10 wt%, and the heating by means of said heater reduces the amount of binder material in the seal material by 50% when compared to the amount of binder material in the seal material before said heating by means of the heater, the amount of binder material in the seal material after it has been heated by the heater and solidified by cooling it will be 5 wt%.

[0848] Fig. 15 illustrates schematically a flow chart relating to VIG unit manufacturing, according to embodiments of the present disclosure. This method may e.g., in some embodiments, be provided by means of a solution as illustrated in fig. 2. Other solutions for VIG unit manufacturing may also and / or alternatively be used.

[0849] In Step S151, a VIG unit assembly 1 is provided. The provided VIG unit assembly may comprise a first glass sheet 2 and a second glass sheet 3, and a plurality of support structures 5 distributed in a gap 6 between a first major surface 2a of the first glass sheet 2 and a first major surface 3a of the second glass sheet 3. A peripheral edge seal 4 is configured to seal the gap 6. The first glass sheet 2 comprises a through hole 10, wherein the through hole 10 extends between the first major surface 2a and a second, oppositely directed, major surface 2b of the first glass sheet 2. The VIG unit assembly may e.g. be an assembly 1 as described according to various embodiments above, see e.g. fig. 1.

[0850] In Step S152, a cover 20 is provided. The cover 20 may comprise a covering body 21 and a solidified seal material 22. The solidified seal material 22 may comprise glass solder material which is attached to a surface 21a of the covering body 21. The provided cover 20 may be a cover 20 as disclosed according to various embodiments above and / or below. The cover 20 is arranged so that the solidified seal material 22 is placed between a surface part 2sp, 10s of the first glass sheet 2 and the covering body 21, and so that the covering body 21 covers at least a part 10a of the through hole 10.

[0851] In Step S153, the vacuum insulated glass VIG unit assembly 1 is heated with the cover 20 in a furnace 70, see e.g. the description to figs. 1 and / or 2 above.

[0852] In Step S154, the gap 6 of the VIG unit assembly is evacuated through the through hole 10 in the first glass sheet. E.g. as described in relation to one or more of figs. 2- 4b. The evacuation of the gap 6 may in some embodiments be provided while the edge seal 4 is heated and softened. In some embodiments, the gap evacuation may provide a vacuum clamping and even deformation of the softened edge seal 4. The vacuum clamping is obtained due to pressure difference between the pressure in the gap 6 and the ambient pressure surrounding the VIG unit assembly. In other embodiments, mechanical clamping may additionally or alternatively be used for providing a clamping force onto the edge seal 4.

[0853] When sufficiently evacuated, the gap 6 is sealed in Step S155 by heating and thereby softening the seal material 22 of the cover, so as to provide that the softened seal material 22 adhere to the surface part 2sp, 10s of the first glass sheet 2 around the through hole 10.

[0854] In some embodiments, prior to sealing the gap 6 by means of the cover 20, the VIG unit assembly may be cooled in order to cool and harden the edge seal 4 after the heating in step S153 and before sealing by means of the cover. Evacuation of the gap 6 may be continued during this cooling.

[0855] Finally, the softened seal material 22 and the VIG unit is cooled in Step S156 to provide the final VIG unit.

[0856] It is understood that the placing of the cover (step S153) in other embodiments instead may be conducted after step S153, such as after step S154.

[0857] Fig. 16 illustrates schematically a flow chart relating to manufacturing of a cover 20 for use for sealing an evacuated gap 6 of a VIG unit, according to embodiments of the present disclosure. This method may e.g., in some embodiments, be provided by means of a solution as illustrated in figs. 13 and / or 14. The cover 20 may be a cover as described according to one or more embodiments above.

[0858] In Step S161 , workpieces for use as covering body 21 are provided. It may e.g. be glass body workpieces or metal body workpieces. In step S162, seal material 22 is applied on a surface of the respective workpiece, e.g. as a continuous seal material ring. This may be provided by means of a nozzle, by means of printing, such as 3D printing, applying by means of smearing and / or the like.

[0859] Then, the workpieces with the applied seal material are placed (Step S163), in a work station. In some embodiments of the present disclosure, the workstation may comprise or be a vacuum chamber (see e.g. fig. 13).

[0860] In some embodiment, step S162 may be provided at the work station. In other embodiments, step S162 may be provided at another location than at the work station.

[0861] If the work station comprises or is a vacuum chamber, the vacuum chamber may be evacuated to reduce the vacuum chamber pressure, see optional step S154. See e.g. embodiments hereof described above. For example, in some embodiments, the reducing of the pressure in the vacuum chamber 50 may comprise reducing the pressure in the vacuum chamber to a pressure below 500 mbar, such as below 100 mbar, such as below 20 mbar, such as to 10 mbar or below, during the cover 20 manufacturing.

[0862] In step 165, the workpieces at the work station is heated so as to soften the seal material. This heating may in some embodiments provide binder and / or solvent burnout. See e.g. one or more embodiments described above in relation to fig. 13 and / or 14.

[0863] The optional evacuation S164 of the vacuum chamber is in fig. 16 illustrated to be started before starting of the heating S165. In other embodiments of the present disclosure, the evacuation S164 may be started during the heating S165.

[0864] The heating of the workpieces is provided (see test TE161) until a target temperature Tar21 of the work piece bodies and the seal material on these is reached. This may be obtained by means of temperature monitoring.

[0865] In some embodiments, a predefined heating scheme may be followed in step S1651 test TE161 which will ensure sufficient heating of the workpiece body and the seal material to a desired target temperature Tar21, e.g. with a defined / controlled heat increase rate as e.g. described in more details above.

[0866] The temperature of the seal material 22 and / or workpiece 21 may be actively monitored (directly or indirectly) by a temperature monitoring system. Alternatively, a predefined heating scheme I heating profile may be designed so as to assure the desired temperature increase to the target temperature without measuring the seal material and / or workpiece temperature. This may be based on e.g. experiential data.

[0867] When the target temperature Tar21 is reached, the workpiece and seal material is cooled, thereby obtaining a cover 20 for use in a VIG unit manufacturing as e.g. described above according to various embodiments of the present disclosure.

[0868] Fig. 17 illustrates schematically evacuation of the gap 6, where gas GA leaves through gas GA passages 25 arranged between the seal material 22 surface 22a and the first glass sheet, according to further embodiments of the present disclosure. A difference between the embodiment illustrated in fig. 3 and the embodiment illustrated in fig. 17 is that the step surface 10s is more plane, and may e.g. be polished or the like to have a surface roughness that is lower, such as at least 10 times lower, e.g. at least 20 times lower or at least 50 times lower than the surface roughness of the seal material 22 surface 22a. This may e.g. be advantageous in relation to provide a good bonding between seal material 22 and step surface 10s. The gas flow GA is therefore primarily or substantially fully made possible due to gas passages 25 arranged between the surface part 10s of the first glass sheet 2 and a surface 22a of the solidified seal material 22 which faces the surface part 10s of the first glass sheet 2. These gas passages 25 are provided / obtained as a consequence of the surface roughness of the solder material 22 surface 22a as e.g. previously described.

[0869] Fig. 18 illustrates a grayscale image of a test example of the surface 22a of a solidified seal material 22 at a cover body 21 surface 21a.

[0870] The surface roughness of the seal material surface 22a can be seen and an envisaged gas passage (dash-dotted line) is indicated. The gas passages 25 are indicated by a white dash-dotted line to improve contrast and readability in the image. The surface 22a roughness may be as e.g. described previously according to various embodiments of the present disclosure. Even though not shown in fig. 18, the solidified seal material 2...

Claims

1. 243Claims1. A cover (20) for use during sealing a through hole (10, 10a) of an evacuated gap (6) of a vacuum insulated glass unit (1), wherein said cover (20) comprises:- a covering body (21),- a major cover surface (21a) at a solder side of the cover (20),- a seal material comprising a solidified glass solder material (22), wherein the glass transition temperature of the solidified glass solder material is lower than the glass transition temperature of the covering body (21), wherein the cover (20) comprises one or more predefined evacuation channels (23) having a channel width (Wc), which channel width (Wc) extends between opposing walls (24a, 24b) of the solidified solder material (22), wherein each of the one or more predefined evacuation channels (23) extends in an evacuation direction (Devac) towards the outer periphery (OP) of the cover (20), wherein the solidified glass solder material (22) covers at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface (21a).

2. The cover (20) according to claim 1 , wherein each of the one or more evacuation channels (23) has a channel width (Wc) and a channel length (Lc), wherein the channel length is larger than the channel width (Wc, Wcmin).

3. The cover (20) according to claim 2, wherein the channel length (Lc) is at least 1.3 times larger, such as at least 2 times larger, such as at least 2.8 times larger than the minimum channel width (Wcmin).

4. The cover (20) according to claim 3, wherein the width (Wc) of the evacuation channel (23) is below 1.8 times, such as below 1.5 times, such as below 1.3 times the minimum channel width (Wcmin) along said channel length (Lc).

5. The cover (20) according to claim 3 or 4, wherein the width (Wc) of the evacuation channel (23) increases, such as by at least 1.1 times, such as at least 1.2 times, such as at least 1.3 times the minimum channel width (Wcmin) along said channel length (Lc).

6. The cover (20) according to any of claims 2-5, wherein the channel width (Wc) of the respective evacuation channel (23), at least along a sub-part (Lc_su) of said channel length (Lc), varies less than 1.7 times, such as less than 1.5 times, such as less than 1.3 times the magnitude of the minimum width (Wcmin) of the evacuation channel (23), wherein said sub-part has a length (Lc_su) that is larger, such as at least 1.3 times larger, such as at least 1.5 times larger or at least 1.7 times larger than the magnitude of the minimum channel width (Wcmin), wherein the sub-part (Lc_su) overlaps the area (A_Wcmin) of the evacuation channel where the minimum channel width (Wcmin) is located.

7. The cover (20) according to any of the preceding claims, wherein said solidified glass solder material (22) of the seal material that is configured to be softened to seal the through hole (10, 10a) during sealing of the VIG unit gap is omitted at a center area (26) of the major cover surface (21a), or wherein the amount of glass solder seal material (22) at the center area (26) of the major cover surface (21a) is reduced, wherein the solidified solder material (22) comprises opposing walls (26a, 26b) facing a space located opposite to the center area (26).

8. The cover (20) according to claim 7, wherein said one or more predefined evacuation channels (23) is configured to be in fluid communication with said space between the walls (26a, 26b) facing the center area (26) when the cover (20) is arranged on a surface so that the surface (22a) of the solidified solder material(22) supports on a surface part (2sp, 10s) of a glass sheet (2) of a vacuum insulated glass (VIG) unit assembly (1), and so that the covering body (21) covers at least a part (10a) of a through hole (10) in the glass sheet (2).

9. The cover (20) according to claim 7 or 8, wherein said center area (26) is larger than the area of the major cover surface (21a) at each of the one or more evacuation channels (22).

10. The cover (20) according to any of claims 7-9, wherein the maximum distance (CAdis) between said walls (26a, 26b) facing the space located opposite to the center area (2) is at least 1.5 times larger, such as at least 2.5 times larger, such as at least 3.5 times larger, than the minimum channel width (Wc) of each of the one or more predefined evacuation channels (23).

11. The cover (20) according to any of the preceding claims, wherein the solidified seal material (22) has a height (H22), such as a maximum height, of at least 0.4 mm, such as at least 0.5 mm, such as at least 0.6 mm.

12. The cover (20) according to any of the preceding claims, wherein the solidified seal material (22) has a height (H22), such as a maximum height, of at least 0.7 mm, such as at least 0.8 mm, such as at least 1 mm.

13. The cover (20) according to any of the preceding claims, wherein the height (22) of the solidified seal material (22) varies by at least 0.1 mm, such as by at least 0.2 mm, such as by at least 0.3 mm over the surface (22a) of the solidified solder material facing away from the covering body (21), such as over the majority of the surface (22a) of the solidified solder material facing away from the covering body (21), thereby causing a surface roughness of the surface (22a) of the solidified seal material (22) forming gas passages (25) in the surface of the solder material, and / or wherein the height (22) of the solidified seal material (22) varies by at least 10%, such as at least 20% or at least 30% over a width direction of the solidified solder material (22), thereby causing a surface roughness of the surface (22a) of the solidified seal material (22) forming gas passages (25) in the surface (22)of the solder material.

14. The cover (20) according to claim 13, wherein said surface roughness of the surface (22a) of the solidified seal material (22) is obtained as a result of a heating a pre-form (SPF) of glass solder material (22) arranged at the covering body so as to burn out binder material and soften the solder material, followed by a subsequent cooling of the softened seal material so as to obtain said solidified seal material.

15. The cover (20) according to any of the preceding claims, wherein said solidified seal material (22) is a solidified seal material that has been obtained from heating a solder material pre-form (SPF) together with the covering body (21) so as to burn out binder material and soften the solder material, followed by a subsequent cooling of the softened seal material so as to obtain said solidified seal material.

16. The cover (20) according to any of claims 14-15, wherein the cover (20) comprises peripheral seal material residue (22k), the peripheral seal material residue being located at the major cover surface (21) adjacent to a foot region of the solidified solder material (20), wherein the seal material residue originates from heating of a seal.

17. The cover (20) according to any of the preceding claims, wherein the distance between the opposing walls (24a, 24b) of the solidified solder material (22) that faces the evacuation channel (23) gradually decreases towards the major cover surface (21a), such as so as to provide a funnel shape when seen in a cross sectional view that is transverse to the longitudinal direction of the evacuation channel (23).

18. The cover (20) according to any of the preceding claims, wherein one or more of the one or more predefined evacuation channels (23) is / are channels that has / have been shaped (58), such as cut, such as laser cut, mechanically cut or etched, into the surface (22a) of the solidified seal (22), for example so that the evacuation channel (23) extends, preferably radially, between an inner side boundary (26a, 26b) of the solidified solder material and to an exterior side boundary of the solidified solder material (27a, 27b).

19. The cover (20) according to any of the preceding claims, wherein the surface area of the major cover surface (21a) is at least 25 mm2, such as at least 35 mm2, such as at least 40 mm2.

20. The cover (20) according to any of the preceding claims, wherein the surface area of the major cover surface (21a) is less than 85 mm2, such as less than at least 65 mm2, such as less than 50 mm2.

21. The cover (20) according to any of the preceding claims, wherein the surface area of the major cover surface (21a) is in the range of 25 - 85 mm2, such as in the range of 35 - 65 mm2, such as in the range of 40 50 mm2.

22. The cover (20) according to any of the preceding claims, wherein the thickness (H2) of the covering body (21), such as a glass covering body, such as a glass disc, is less than 2.4 mm, such as less than 2 mm, such as less than 1.8 mm.

23. The cover (20) according to any of the preceding claims, wherein the thickness (H2) of the covering body (21), such as a glass covering body, such as a glass disc, is larger than 1 mm, such as larger than 1.3 mm, such as larger than 1.4 mm.

24. The cover (20) according to any of the preceding claims, wherein the thickness (H2) of the covering body (21) is between 1 mm and 2.4 mm, such as between 1.3 mm and 2.3 mm, such as between 1.7 mm and 2.2 mm (endpoints included).

25. The cover (20) according to any of the preceding claims, wherein the thickness (H2) of the covering body (21) is between 1.5 mm and 2.4 mm, such as between 1.7 mm and 2.2 mm, such as between 1.9 mm and 2.2 mm (endpoints included).

26. The cover (20) according to any of the preceding claims, wherein the covering body (21) is substantially circular and has a diameter of at least 4 mm, such as at least 5 mm, such as at least 6.5 mm.

27. The cover (20) according to any of the preceding claims, wherein the covering body (21) is substantially circular and has a diameter of less than 12 mm, such as less than 10 mm, such as less than 9 mm.

28. The cover (20) according to any of the preceding claims, wherein the covering body (21) is substantially circular and has a diameter in the range of 4 mm - 12 mm, such as in the range of 5 mm - 10 mm, such as in the range of 6.5 mm - 9 mm (endpoints included).

29. The cover (20) according to any of the preceding claims, wherein the covering body (21) comprises or consists of a glass body, such as a structural glass body, such as an annealed glass body.

30. The cover (20) according to any of the preceding claims, wherein the total volume of said solidified solder material (22) at the major cover surface (21a) is at least 6 mm3, such as at least 8 mm3, such as at least 10 mm3.24831. The cover (20) according to any of the preceding claims, wherein the total volume of said solidified solder material (22) at the major cover surface (21a) is less than 30 mm3, such as less than 20 mm3, such as less than 15 mm3.

32. The cover (20) according to any of the preceding claims, wherein the total volume of said solidified solder material (22) at the major cover surface (21a) is in the range of 6 - 30 mm3, such as in the range of 6 - 18 mm3, such as in the range of 8 - 15 mm3.

33. The cover (20) according to any of the preceding claims, wherein the height (He) of the evacuation channel (23) is at least 0.5 mm, such as at least 0.7 mm, such as at least 0.9 mm.

34. The cover (20) according to any of the preceding claims, wherein the minimum cross sectional area (He x Wc) of each of the one or more channels (23), when the cover is arranged so that the surface (22a) of the solidified solder material supports (fig. 32) on a surface (10c) of a glass sheet (2), is less than 3 mm2, such as less than 2.5 mm2, such as less than 1.5 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction (LDC) of the evacuation channel (23)35. The cover (20) according to any of the preceding claims, wherein the minimum cross sectional area (He x Wc) of each of the one or more channels (23), when the cover is arranged so that the surface (22a) of the solidified solder material (22) supports on a surface (10c) of a glass sheet (2), is in the range of 0.08 - 3 mm2, such as in the range of 0.1 - 2.5 mm2, such as in the range of 0.2 -1.5 mm2, which cross sectional area extends substantially perpendicular to the longitudinal direction (LDC) of the evacuation channel (23)36. The cover (20) according to any of the preceding claims, wherein the evacuation channel height (He), such as the minimum height, is larger than the width (Wc), such as the minimum width, of the evacuation channel (23).

37. The cover (20) according to any of the preceding claims, wherein the evacuation channel (23) height (He), such as minimum evacuation channel height, is within ±70%, such as within ±50% (Wc), such as within ±30% of the evacuation channel (23) width (Wc), such as the minimum evacuation channel width.24938. The cover (20) according to any of the preceding claims, wherein one or more gas passages (25) in the surface (22a) of the solidified glass solder material (22) of the cover (20) is / are provided as a consequence of a surface roughness of the surface (22a), wherein said one or more gas passages (25) are separate to the one or more predefined evacuation channels (23)39. The cover (20) according to claim 38, wherein the surface roughness of the surface (22a) of the solidified seal material (22) which faces said surface part (2sp, 10s) of the first glass sheet (2) is above 10 pm, such as above 25 pm, such as above 35 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

40. The cover (20) according to claim 38 or 39, wherein said surface roughness of the surface (22a) of the solidified seal material (22) is obtained as a result of a pre-heating (60) of the seal material (22) of the cover (20), and a subsequent pre-cooling of the softened seal material (22) so as to solidify the seal material.

41. The cover (20) according to any of claims 38-40, wherein said surface roughness of the solidified seal material (22) surface (22a) of the cover (20) is the surface roughness over at least 90%, such as at least 95%, such as at least 98% of the surface area of the solidified seal material (22) surface (22a) which is unbonded to the surface (21a) of the covering body (21).

42. The cover (20) according to any of the preceding claims, wherein one or more of the one or more predefined evacuation channels (23) is a channel that has been shaped, such as by means of a shaping tool, after the solder material has solidified, such as after the solder material has been heated to be softened and then cooled so as to solidify the softened solder material (22).

43. The cover (20) according to any of the preceding claims, wherein one or more of the one or more predefined evacuation channels (23) is a channel that originates from a pre-shaped channel (23) provided in the solder material pre-form (SPF) prior to solidifying said solder material (22), such as wherein said solidifying of the solder250 material comprises heating the solder material (22) to obtain binder burnout and to soften the solder material (22), and then cooling the solder material so as to solidify the softened solder material (22).

44. The cover (20) according to any of the preceding claims, wherein the amount of binder material in the solidified seal material (22) is below 5 wt%, such as below 2 wt%, such as below 1 wt% or below 0.1 wt%.

45. The cover (20) according to any of the preceding claims, wherein the amount of solvent in the solidified seal material (22) is below 4 wt%, such as below 2 wt%, such as below 1 wt% or below 0.2 wt%.

46. The cover (20) according to any of the preceding claims, wherein the solidified glass solder material covers at least 65%, such as at least 71%, of the area of the major cover surface (21a), or wherein the solidified glass solder material covers at least 55%, such as at least 59%, of the area of the major cover surface (21a), and / or47. The cover (20) according to any of the preceding claims, wherein the solidified glass solder material covers less than 100%, such as less than 95%, such as less than 85% of the area of the major cover surface (21).

48. The cover (20) according to any of the preceding claims, wherein the solidified glass solder material covers between 40% and 100%, such as between 50% and 90%, such as between 50% and 73%, of the area of the major cover surface 21a.

49. The cover (20) according to any of the preceding claims, wherein the thickness (H2) of the covering body, such as a glass body, is between 0.9 mm and 2.4 mm, such as between 1.6 mm and 2.2 mm, such as between 1.8 mm and 2.1 mm, endpoints included.

50. The cover (20) according to any of the preceding claims, wherein one or more of said one or more evacuation channels (23) constitutes a discontinuation.25151. The cover (20) according to any of the preceding claims, wherein the opposing walls (24a, 24b) of the solidified solder material (22) are convexly shaped so that the width of the evacuation channel(s) (23) gradually increases from the minimum channel width (Wcmin) along the length of the evacuation channel.

52. The cover (20) according to any of the preceding claims, wherein the distance between the opposing walls (24a, 24b) of the solidified solder material (22) facing the predefined channel(23) gradually increases along the length of the evacuation channel from a minimum channel width (Wcmin).

53. The cover (20) according to any of the preceding claims, wherein the seal material comprises at least one primer layer (28), such as a single primer layer or a multilayer primer layer, positioned between the solidified glass solder material (22) and the covering body (21).

54. Cover (20) according to claim 53, wherein the primer layer (28) is arranged so as to cover at least the same area of the major surface (21a) of the covering body (21) as is covered by the seal material (22).

55. Cover (20) according to claim 53 or 54, wherein the primer layer (28) is arranged so as to cover substantially the whole major surface (21a) of the covering body (21) except a center area (26), such as wherein the primer layer (28) forms a ring around the center area (26).

56. Cover (20) according to any of claims 53-55, wherein the primer layer (28) comprises a material with a glass transition temperature Tg that is lower than the glass transition temperature of the covering body (21) and higher than the glass transition temperature of the seal material (22).

57. Cover (20) according to any of claims 53-56, wherein the primer layer (28) covers between 50% and 100%, such as between 70% and 100%, such as between 70% and 93% (Fig. 49) of the major surface (21a) of the covering body.25258. Cover (20) according to any of claims 53-57, wherein the primer layer (28) covers (Fig. 49) an area that is larger, such as at least 5% larger, such as at least 15% larger or at least 20% larger than the area covered by the solidified solder material (22).

59. The cover (20) according to any of the preceding claims, wherein the solidified glass solder material (22) comprises one or more inorganic oxides selected from the group of oxides of Li, B, Na, Mg, Al, Si, P, K, V, Mn, Zn, Rb, Ag, Sn, Te, Ba and / or Bi, such as wherein the glass seal material (22) comprises one or more oxides of Te and / or V, such as comprising one or more of V2O5, VO2, and / or V2O3 in combination with TeC>2, TeCL, TeOs, and / or TesCL.

60. The cover (20) according to any of the preceding claims, wherein the solidified glass solder material (22) comprises more tellurium oxide than vanadium oxide by weight, such as wherein the solidified glass solder material (22) additionally comprises one or more of AI2O3, SiC>2, MgO, P2O5, Bi2Os, ZnO, Nb20s, Ag2O, and / or MnO.61 . The cover (20) according to any of the preceding claims, wherein the solidified glass solder material (22) comprises Bi2C>3,such as in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

62. Method of manufacturing a vacuum insulated glass unit, the method comprising: providing a vacuum insulated glass (VIG) unit assembly (1), wherein the vacuum insulated glass (VIG) unit assembly (1) comprises:- a first glass sheet (2) and a second glass sheet (3),- a plurality of support structures (5) distributed in a gap (6) between a first major surface (2a) of the first glass sheet (2) and first major surface (3a) of the second glass sheet (3),- a peripheral edge seal (4) which is configured to seal the gap (6),- wherein the first glass sheet (2) comprises a through hole (10), wherein the through hole (10) extends between the first major surface (2a) and a second, oppositely directed, major surface (2b) of the first glass sheet (2), providing a cover (20), wherein the provided cover (20) comprises:- a covering body (21),- a major cover surface (21a) at a solder side of the cover (20),253 a solidified glass solder material (22), wherein the glass transition temperature of the solidified glass solder material is lower than the glass transition temperature of the covering body (21), wherein the solidified glass solder material (22) of the provided cover (20) covers at least 40%, such as at least 50%, such as at least 70% of the area of the major cover surface (21a), wherein the cover (20) comprises one or more predefined evacuation channels (23) having a channel width (Wc), which channel width (Wc) extends between opposing walls (24a, 24b) of the solidified solder material (22), and wherein each of the one or more predefined evacuation channels (23) extends in an evacuation direction (Devac) towards the outer periphery (OP) of the cover (20), the method further comprising: arranging the provided cover (20) so that the solidified seal material (22) is placed between a surface part (2sp, 10s) of the first glass sheet (2) and the covering body (21), and so that the covering body (21) covers at least a part (10a) of the through hole (10), evacuating the gap (6) of the vacuum insulated glass (VIG) unit assembly (1) by means of a pump (30), so that gas (GA), such as air, in the gap (6) is evacuated through the through hole (10), heating the solidified seal material (22) by means of a heater (7) so as to soften the solidified seal material, thereby providing that the softened seal material (22) adhere to the surface part (2sp, 10s) of the first glass sheet (2) around the through hole (10), cooling the softened seal material (22) so as to harden the softened seal material, thereby sealing the evacuated gap (6).

63. Method according to claim 62, wherein said provided cover is a cover according to any of claims 1-61.

64. Method according to claim 62 or 63, wherein the evacuation channel (23) height (He), such as the minimum height, is larger than the width (Wc), such as the minimum width, of the evacuation channel (23).

65. Method according to claim 62, 63 or 64, wherein one or more gas passages (25) in the solidified glass solder material (22) of the cover (20) is / are provided as a consequence of a surface roughness of said surface part (2sp, 10s) of the first glass sheet (2),254 such as wherein the surface roughness of the solidified seal material (22) surface (22a) is provided by means of protrusions at / in the surface of the seal material (22) of the cover (20), wherein said protrusions are arranged staggered and / or substantially randomly, across the surface of the glass solder material (22).

66. Method according to any of claims 62-65, wherein said surface roughness of the surface (22a) of the solidified solder material (22) is obtained as a result of a preheating (60) of the solder material (22) of the cover (20), and a subsequent pre-cooling of the softened solder material (22) so as to solidify the solder material, and / or wherein surface roughness at least partly is caused by outgassing of the glass solder material during manufacturing of the cover.

67. Method according to any of claims 62-66, wherein the method comprises providing said through hole (10), such as the full through hole, in the first glass sheet (2), wherein said providing of the through hole (10) comprises laser cutting at least a part of the through hole in the first glass sheet (2), wherein said laser cutting is conducted prior to or during assembling of the vacuum insulated glass (VIG) unit assembly (1).

68. Method according to any of claims 62-67, wherein the first glass sheet (2) is a tempered glass sheet, such as a thermally tempered glass sheet, such as wherein said laser cutting is provided prior to tempering of the first glass sheet (2).

69. Method according to any of claims 62-68, wherein a clamping force (F1) is provided by means of a clamping part (40) so as to force the covering body (21) towards said surface part (2sp 10s) of the first glass sheet (2), such as during and / or after said heating of the solidified solder material (22) so as to soften the solidified solder material.

70. Method according to claim 69, wherein the clamping force (F1) directly or indirectly pushes the covering body (21) so as to deform the softened seal material (22).

71. Method according to any of claims 69-70, wherein the clamping force (F1) pushes the covering body (21) so as to provide that a part of the softened seal material (22) moves in between a side surface (21c) of the covering body (21) and a side surface255(10bs) of the first glass sheet which faces the side surface (21c) of the covering body (21).

72. Method according to any of claims 69-71, wherein the clamping part (40) comprises a spring configured to provide said clamping force (F1).

73. Method according to any of claims 62-72, wherein the method comprises arranging an evacuation cup (9), such as on the second surface (2b) of the first glass sheet, so as to cover the through hole, wherein said evacuation of the gap (6) comprises evacuating the gap by means of a pump (30) which is in fluid communication (30a) with an interior cavity (9a) of the evacuation cup (9).

74. Method according to claim 69 and 73, wherein the clamping part (40) is arranged inside the evacuation cup (9), such as is attached to a housing (9b) of the evacuation cup.

75. Method according to any of claims 62-74, wherein said heating of the solidified solder material (22) of the cover (20) so as to soften the solidified solder material (22) to provide that the solder material (22) adhere to the surface part of the first glass sheet (2) around the through hole (10) comprises heating by radiation heating provided by means of a radiation heater (7) which emits a heating beam (7a), such as wherein said radiation heater (7) comprises a laser, and wherein said heating beam (7a) is a laser beam.

76. Method according to any of claims 62-75, wherein the through hole (10) is a stepped through hole comprising a smaller diameter portion (10a) and a larger diameter portion (10b), wherein the larger diameter portion (10b) is arranged proximate the second surface (2b) of the first glass sheet (2) and wherein the smaller diameter portion (10a) is arranged proximate the gap (6), a step surface (10s, 2sp) arranged between the larger diameter portion (10b) and the smaller diameter portion (10a), wherein said arranging of the cover (20) comprises arranging the solidified solder material (22) opposite to, such as so as to support on, the step surface (10s, 2sp) so256 that the covering body (21) is arranged in the larger diameter portion (10b) and covers the smaller diameter portion (10a).

77. Method according to claim 76, wherein the diameter (D1) of the larger diameter portion (10b) is at least 2 mm, such as at least 3 mm, larger than the diameter (D2) of the smaller diameter portion (10a) and / or wherein the diameter (D1) of the larger diameter portion (10b) is between 5 mm and 12 mm, such as between 6 mm and 9 mm.

78. Method according to claim 76 or 77, wherein the diameter (D3) of the covering body (21) is smaller than the diameter (D1) of the larger diameter portion (10b), wherein the difference in diameter (D1-D3) between the diameter (D3) of the covering body (21) and the diameter (D1) of the larger diameter portion (10b) is less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

79. Method according to any of claims 76-78, wherein the depth (DE1) of the larger diameter portion (10b) is between 1 mm and 4 mm, such s between 1.5 mm and 3 mm, such as between 1.9 mm and 2.5 mm, such as between 1.9 mm and 1.2 mm, or wherein the depth (DE1) of the larger diameter portion (10b) is between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm, such as between 1.6 mm and 2 mm.

80. Method according to any of claims 62-79, wherein the maximum thickness (H3) of the seal material (22) between the covering body (21) and said surface part (2sp, 10s) of the first glass sheet (2), after said sealing of the gap (6), is between 0.050 mm and 0.4 mm, such as between 0.075 mm and 0.3 mm, such as between 0.125 mm and 0.250 mm.

81. Method according to any of claims 62-80, wherein the method of manufacturing the vacuum insulated glass (VIG) unit comprises laminating the vacuum insulated glass (VIG) unit (100), wherein said lamination of the vacuum insulated glass (VIG) unit (100) comprises attaching a lamination glass sheet (8) to the second major surface (2b) of the first glass sheet (2) by means of a lamination interlayer (8a) so that the lamination glass sheet (8)257 extends over and covers the cover (20) and the through hole (10), such as wherein the lamination interlayer adheres to the covering body (21).

82. Method according to any of claims 62-81, wherein the first glass sheet (2) and / or the second glass sheet (3) is a tempered glass sheet (2) such as a thermally tempered glass sheet.

83. Method according to any of claims 62-82, wherein the average flow resistance from the gap (6) to the ambient environment, such as the interior (9a) of an evacuation cup, when determined in seconds per liter (s / L) evacuated gas, is less than 30 s / L, such as less than 20 s / L, such as less than 18 s / L.

84. Method according to any of claims 62-83, wherein the average flow resistance (AR1) determined in seconds per liter (s / L) in the area of the through hole (10a), such as a lower diameter portion of the through hole, is less than 15 (s / L), such as less than 10 s / L, such as less than 8 s / L85. Method according to any of claims 62-84, wherein, the average flow resistance in the area (AR2) from the through hole (10a), such as a lower diameter portion, and past (23, 25) the solidified solder material (22), determined in seconds per liter (s / L), is less than 10 (s / L), such as less than 8 s / L, such as less than 4 s / L.

86. Method according to any of claims 62-85, wherein the average flow resistance in an area (AR3) from the solidified solder material (22) and in between the side surface (21c) of the covering body (21) and a side surface part (10bs) of the first glass sheet (2) enclosing a larger diameter portion of the through hole (10a), determined in seconds per liter (s / L), is less than 15 (s / L), such as less than 9 s / L, such as less than7 s / L.

87. The method according to any of claims 62-86, wherein the first glass sheet (2) comprises a plurality of discrete support standoffs (97) spaced, for example circumferentially, around the through-hole, wherein the spacing (97a) between the support standoffs forms gas-flow passages extending between the standoffs, the surface (22a) of the solidified glass solder material, and the surface of the first glass sheet extending between adjacent standoffs (97),25888. The method according to claim 87, wherein the plurality of discrete support standoffs (97) are integral with the first glass sheet (2), such as by being shaped into the first glass sheet by means of laser cutting, such as during providing the through hole.

89. The method according to any of claims 62-88, wherein the method comprises the step of placing and storing each of the one or more covers (20) in a controlled, such as reduced, such as sealed, atmosphere environment in a container until they are to be used, such as used for sealing the gap (6) of a VIG unit (1).

90. A Vacuum insulated glass unit (100) manufactured by means of a method according to any of claims 62-89, comprising:- a first glass sheet (2) and a second glass sheet (3),- a plurality of support structures (5) distributed in an evacuated gap (6) between a first major surface (2a) of the first glass sheet (2) and first major surface (3a) of the second glass sheet (3),- a peripheral edge seal (4) which is configured to seal the evacuated gap (6),- wherein the first glass sheet (2) comprises a through hole (10), wherein the through hole (10) extends between the first major surface (2a) and a second, oppositely directed, major surface (2b) of the first glass sheet (2), a cover (20) comprising a covering body (21a), wherein glass solder material (22) is placed between a surface part (2sp, 10s) of the first glass sheet (2) and a major surface (21a) of the covering body (21), and wherein the covering body (21) covers the through hole (10), wherein said glass solder material (22) has a the glass transition temperature that is lower than the glass transition temperature of the covering body (21), wherein the glass solder material (22) of the provided cover (20) covers at least 50%, such as at least 60%, such as at least 70% of the area of a major cover surface (21a) of the cover.

91. A Vacuum insulated glass unit (100) according to claim 90, wherein the first glass sheet (2) and the second glass sheet (3) are tempered glass sheets such as a thermally tempered glass sheets, wherein the covering body (21) comprises a glass body,259 wherein the through hole (10) is a stepped through hole comprising a smaller diameter portion (10a) and a larger diameter portion (10b), wherein the larger diameter portion (10b) is arranged proximate the second surface (2b) of the first glass sheet (2) and wherein the smaller diameter portion (10a) is arranged proximate the evacuated gap (6), wherein a step surface (10s, 2sp) is arranged between the larger diameter portion (10b) and the smaller diameter portion (10a), wherein said glass solder material (22) is placed between the step surface (10s, 2sp) and the covering body (21) so that the covering body (21) is arranged in the larger diameter portion (10b) and covers the smaller diameter portion (10a), wherein the depth (DE1) of the larger diameter portion (10b) extends over less than 60% of the thickness (TH1) of the first glass sheet (2), wherein the depth (DE1) of the larger diameter portion (10b) is between 1 mm and 3 mm, such as between 1.4 mm and 2.2 mm, wherein the maximum thickness (H3) of the glass solder material (22) between the covering body (21) and said surface part (2sp, 10s) of the first glass sheet (2) is less than 0.4 mm, wherein the thickness (H2) of the covering body (21) is at least 30% lower, such as at least 50% lower than the thickness (TH1) of the first glass sheet (2) and wherein the thickness (H2) of the covering body (21) is lower than the depth (DE1) of the larger diameter portion (10b), optionally wherein the difference in diameter (D1-D3) between the diameter (D3) of the covering body (21) and the diameter (D1) of the larger diameter portion (10b) is less than 1 mm, such as less than 0.6 mm, such as less than 0.4 mm.

92. A method of manufacturing one or more covers (20) for use, such as subsequent use, during sealing of an evacuated gap (6) of a vacuum insulated glass unit (1), such as a cover according to any of the preceding claims, wherein the method comprises:- providing one or more covering body workpieces (21), wherein said one or more covering body workpieces (21) comprises a seal material, which seal material comprises a glass solder material (22), wherein the seal material (22) is arranged at a surface (21a) of the one or more covering body workpieces (21),- arranging the one or more covering body workpieces (21) in a working space (50),260- heating the seal material (22) in the working space (50) to a target temperature (Tar21) by means of a heater (60), such as wherein said heating is provided so as to provide an outgassing of the glass solder material,- cooling the one or more heated covering body workpieces (21) and seal material (22) so as to solidify the seal material (22),- obtaining one or more covers (20) from the one or more cooled covering body workpieces (21).

93. Method according to claim 92, wherein said heating of the seal material (22) comprises heating to a temperature between 200°C and 450°C, such as between 300°C and 400°C, such as between 320°C and 370°C.

94. Method according to any of claims 92-93, wherein said working space (50) comprises or is a vacuum chamber, and wherein the pressure is reduced in the vacuum chamber (50), such as by means of a pump (80), at least while said glass solder material (22) is heated in the vacuum chamber.

95. Method according to any of claims 92-94, wherein said heating of the seal material (22) comprises one or more controlled temperature (TStep, Tbb) holding periods, such as constant temperature holding periods, between the time of initiating the heating (Tinit) and time (Tend) of reaching the target temperature (Tar21).

96. Method according to any of claims 92-95, wherein the heat increase rate, such as heating gradient, is decreased (Figs. 41A-41C) as the temperature (T21) of the seal material (22) is increased.

97. Method according to any of claims 92-96, wherein said heating of the seal material (22), such as until the target temperature (Tar21) is reached, comprises heating at a controlled, such as constant, binder burnout temperature (Tbb) holding period, such as a constant binder burnout temperature (Tbb) holding period, at a temperature (Tbb) in the range of 200 - 320 °C, such as in the range of 230 - 290 °C, such as in the range of 250 - 270 °C.26198. Method according to claim 97, wherein the controlled, such as constant, binder burnout temperature (Tbb) holding period has a duration of at least 15 minutes, such as at least 30 minutes, such as at least 60 minutes, and / or wherein the controlled, such as constant, binder burnout temperature (Tbb) holding period, such as constant binder burnout temperature (Tbb) holding period, has a duration in the range of 15 minutes - 2 hours, such as in the range of 30 minutes - 1.5 hours, and / or wherein the binder burnout temperature (Tbb) holding period, such as constant binder burnout temperature (Tbb) holding period, has a duration of less than 3 hours, such as less than 2 hours, such as less than 1.5 hours.

99. Use of a cover (20) according to any of claims 1-61 for covering and sealing of an evacuation hole (10) in a glass sheet (2) of a vacuum insulated glass unit (1) so as to seal an evacuated gap (6) of a vacuum insulated glass unit (1).

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