Cover comprising solidified seal material

Abstract

The present disclosure regards a method of manufacturing covers (20) for use during sealing of an evacuated gap (6) of a vacuum insulated glass unit (1). The method comprises providing a plurality of covering body workpieces (21), wherein said plurality of covering body workpieces comprises a seal material (22) comprising a glass solder material, wherein the seal material is arranged at a surface of each of the provided plurality of covering body workpieces. Said plurality of covering body workpieces (21) are arranged in a working space. The seal material (22) is heated in the working space to a target temperature (Tar21) by means of a heater (60). The heating may be provided so as to provide an outgassing of the glass solder material (22). The heated covering body workpiece (21) and outgassed glass solder material (22) is thereafter cooled so as to solidify the seal material (22). A method of manufacturing a vacuum insulated glass unit (1) is also disclosed.

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.

[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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] Patent document LIS2021388667 discloses providing an exhaust channel passage through which gas is exhausted.

[0012] 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.

[0013] Summary

[0014] The present disclosure relates, in a first aspect, to a method of manufacturing one or more covers. The one or more covers may be configured for subsequent use during sealing of an evacuated gap of a vacuum insulated glass unit. The method comprises providing one or more covering body workpieces. The provided one or more covering body workpieces comprises a seal material comprising a glass solder material. The seal material is arranged at a surface of the one or more covering body workpieces. The one or more covering body workpieces is / are arranged in a working space. The seal material is heated in the working space to a target temperature by means of a heater. The one or more heated covering body workpieces and seal material is / are then cooled so as to solidify the seal material. One or more covers is / are obtained from the one or more cooled covering body workpieces.

[0015] 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.

[0016] 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 10-2mbar, such as 10-3mbar 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.

[0017] 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.

[0018] 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.

[0019] 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. The seal material at the workpiece(s) may in some embodiments of the present disclosure comprise or be a solder glass material, such as a low melting point solder glass material, such as a glass frit material.

[0020] In some embodiments, the seal material at the work piece(s) may consist of a solder glass material, such as a low melting point solder glass material, such as a glass frit material.

[0021] The seal material may in some embodiments of the present disclosure comprise binder material and / or solvent material, at least prior to said heating of the solder material.

[0022] The cover manufacturing may be a batch manufacturing. In other embodiments, it may be a continuous process manufacturing.

[0023] The covering body workpieces may be heated by means of heating the seal material of the cover and / or by means of conduction heating, convection heating and or the like provided by means of the heater. The covering body workpieces may be heated directly or indirectly by means of the heater.

[0024] The target temperature may be predefined, such as preset.

[0025] The cover comprises a seal material which may be e.g. the glass solder material.

[0026] In one or more embodiments of the present disclosure, said heating of the seal material may comprise heating to a target temperature above 200°C, such as above 300°C, such as above 350°C.

[0027] 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. In some embodiments of the present disclosure, the heating of the seal material may comprise 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.

[0028] In some embodiments of the present disclosure, said working space may be a vacuum chamber, and the pressure may be reduced in the vacuum chamber, such as by means of a pump. In some embodiments, the pressure may be reduced in the vacuum chamber while the seal material is heated in the vacuum chamber.

[0029] 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.

[0030] In some embodiments of the present disclosure, 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.

[0031] In some embodiments of the present disclosure, said reducing of the pressure in the vacuum chamber may comprise reducing the pressure in the vacuum chamber to a pressure below 500 millibar such as below 100 millibar.

[0032] 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.

[0033] In some embodiments of the present disclosure, said heating may comprise heating the seal material comprising the glass solder material of the cover to a temperature above the rated glass transition temperature of the glass solder material. 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.

[0034] In some embodiments of the present disclosure, said heater may comprise a radiation heater. In some embodiments of the present disclosure, the radiation heater may comprise a laser. Radiation heating may e.g. enable providing a controlled and / or adapted heating of the seal material.

[0035] In one or more embodiments of the present disclosure, 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. 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] In one or more embodiments of the present disclosure, the temperature of the seal material may be 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. The inventors have seen indications that a slow heating of the seal material, such as a glass solder frit material, may be advantageous in order to obtain covers with solidified seal 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.

[0040] In one or more embodiments of the present disclosure, the temperature of the seal material may be 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.

[0041] 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.

[0042] In some embodiments of the present disclosure, said heat increase rate may be provided over at least 50%, such as over at least 70% or over at least 95% of said heating time.

[0043] In some embodiments of the present disclosure, 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.

[0044] In some embodiments of the present disclosure, the heating time before the seal material reaches the target temperature is at least 30 minutes, such as at least 1 hour.

[0045] In some embodiments of the present disclosure, the heating time 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. In one or more embodiments of the present disclosure, the amount of binder material in the solidified seal material may be below 5 wt%, such as below 2 wt%, such as below 1 wt%. However, in some embodiments, an amount of binder material may be maintained in the seal material at the cover in order to obtain e.g. advantageous seal material properties.

[0046] In some embodiments of the present disclosure, the amount of solvent in the solidified seal material may be below 4 wt%, such as below 2 wt%, such as below 1 wt%. In some embodiments of the present disclosure, the amount of solvent in the solidified seal material may be below 0.5 wt%, such as below 0.1 wt%.

[0047] In some embodiments of the present disclosure, said heating by means of said heater may reduce 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 of binder material in the seal material before said heating by means of the heater.

[0048] In some embodiments of the present disclosure, the amount of binder material in the seal material 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%.

[0049] In some embodiments of the present disclosure, the amount of binder material in the seal material after it has been heated by the heater and solidified by cooling it, may be between 0.1 wt% and 5 wt%, such as between 0.4 wt% and 2 wt%.

[0050] In one or more embodiments of the present disclosure, said heating by means of said heater may reduce the amount of solvent material in the seal material by at least 40 wt%, such as at least 80 wt%, such as at least 95 wt% when compared to the amount of solvent material in the seal material before said heating by means of the heater (60).

[0051] In one or more embodiments of the present disclosure, a surface roughness of the surface of the solidified seal material which faces away from the surface of the work piece may be 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. In one or more embodiments of the present disclosure, the surface roughness of the surface of the solidified seal material which faces away from the surface of the work piece may be between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 75 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0052] 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.

[0053] 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.

[0054] 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 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.

[0055] 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.

[0056] 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. Surface roughness may be defined according to ISO 21920, such as ISO 21920-2.

[0057] In one or more embodiments of the present disclosure, said providing of the one or more covering body workpieces may comprise applying the glass solder material to a surface of the one or more covering body workpieces.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In one or more embodiments of the present disclosure, a softening temperature of the one or more covering body workpieces may be higher than a softening temperature of the glass solder material.

[0062] 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.

[0063] 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.

[0064] In one or more embodiments of the present disclosure, a surface roughness of the surface of the solidified seal 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.

[0065] In one or more embodiments of the present disclosure, the surface roughness of the surface of the solidified seal material which faces away from the surface of the work piece may be between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 80 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0066] 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.

[0067] 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.

[0068] In some embodiments of the present disclosure, said surface roughness of the surface of the solidified seal material, such as of the surface of the glass solder material, may be 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.

[0069] In some embodiments of the present disclosure, 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 seal material surface which is unbonded to the surface of the covering body. In one or more embodiments of the present disclosure, said solidified seal material may have 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. This may e.g. provide a more space saving solution and / or a cost efficient solution.

[0070] In one or more embodiments of the present disclosure, the height, such as local maximum height, of the solidified seal material varies less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm over the entire extent of the seal material.

[0071] 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.

[0072] In one or more embodiments of the present disclosure, the surface roughness of the seal material surface may be 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.

[0073] 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.

[0074] 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.

[0075] In one or more embodiments of the present disclosure, the solidified seal material may comprise or consist of a continuous ring of seal material, such as a continuous, annular ring of seal material. 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.

[0076] In one or more embodiments of the present disclosure, the solidified seal 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.

[0077] 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.

[0078] In other embodiments, the covering body may comprise or consist of a structural metal body or a structural ceramic body.

[0079] In some embodiments of the present disclosure, the thickness of the covering body (21) may be 2.5 mm or less, such as 1.5 mm or less.

[0080] 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).

[0081] 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.

[0082] 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.

[0083] For example, such materials may be more easy to cut after the seal material has been solidified.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] The present disclosure moreover relates, in a second aspect, to use of a cover according to 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. The vacuum insulated glass unit may be for use in a building window such as a roof window.

[0091] The use of the cover may comprise that the solidified seal material is re-heated by means of a heater to soften the solidified seal material while the gap is evacuated. A clamping part I pushing part may or may not be used. The clamping part I pushing part is configured to provide a pushing force onto the covering body so as to press the cover towards a surface and in some embodiments thereby compress and deform the heated, softened seal material of the cover.

[0092] The present disclosure moreover relates, in a third aspect, to a method of manufacturing a vacuum insulated glass unit. The method comprises: providing a vacuum insulated glass unit assembly, wherein the vacuum insulated glass unit assembly comprises:

[0093] - a first glass sheet and a second glass sheet,

[0094] - 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,

[0095] - a peripheral edge seal which is configured to surround and seal the gap,

[0096] - 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.

[0097] The method according to the third aspect further comprises: providing a cover comprising a covering body and a solidified seal material, wherein the solidified seal material comprises glass solder material, wherein the seal material is attached to a surface of the covering body, 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, evacuating the gap of the heated 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, and cooling the softened seal material so as to harden the softened seal material, thereby sealing the evacuated gap.

[0098] 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.

[0099] 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.

[0100] For example, in some embodiments, advantageous evacuation of the gap of the VIG unit assembly may be obtained.

[0101] For example, in some embodiments, "vacuum clamping" of the peripheral edge seal may be enabled in a more simple way.

[0102] In some embodiments, said seal material of the covering body comprises glass solder material.

[0103] The solidified seal material of the 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.

[0104] In one or more embodiments of the third aspect, 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.

[0105] In some embodiments of the third aspect, said provided cover is a cover may be a cover according to one or more embodiments of the first aspect and / or according to one or more of items 1-33.

[0106] In one or more embodiments of the third aspect, said evacuation of the gap by means of the pump may comprises that the gas is evacuated from the gap through one or more gas passages), wherein the one or more gas passages is / are arranged between said surface part of the first glass sheet and a surface of the solidified seal material which faces said surface part of the first glass sheet.

[0107] This may e.g. enable a solution where improved sealing options may be obtained and / or a more simple cover manufacturing may be allowed. Hence, instead of terminating the solder material at one or more predefined locations at the cover surface so as to provide a predefined flow path for evacuated air through the seal material, one or more gas passages may be arranged between the surface part of the first glass sheet and a surface of the solidified seal material which faces said surface part of the first glass sheet.

[0108] The seal material may thus be configured to extend continuously and uninterrupted and with substantially no discontinuations so that no predetermined flow tunnel is formed by and between the second surface of the first glass sheet, the surface of the covering body, and between opposing side surface parts of the seal material facing a predefined flow path. In other embodiments, however, a discontinuation may be provided in order to enable or improve gap evacuation.

[0109] Said surface part of the first glass sheet and the surface of the solidified seal material which faces said surface part of the first glass sheet may thus abut the gas passage.

[0110] In one or more embodiments of the third aspect, the surface of the solidified seal material supports, such as directly supports, on the surface part of the first glass sheet during said evacuation of the gap by means of the pump.

[0111] This may e.g. enable more simple VIG unit manufacturing and / or more simple sealing of the gap. Instead, the cover may support directly on the surface part of the first glass sheet, and when the gap is to be seal after it has been evacuated, the seal material of the cover may be heated and softened.

[0112] In some embodiments, prior to the heating and softening of the seal material of the cover, the flow path may be present between the seal material and the surface part of the first glass sheet on which the solidified seal material supports.

[0113] In one or more embodiments of the third aspect, at least 80%, such as at least 95%, such as at least 98%, of the evacuated gas may be evacuated through said one or more gas passages.

[0114] Said one or more gas passages arranged between said surface part of the first glass sheet and the surface of the solidified seal material may thus be the primary gas passages, or even substantially the sole gas passages for the evacuated gas from the gap of the VIG unit assembly.

[0115] In one or more embodiments of the third aspect, said one or more gas passages may be provided as a consequence of a surface roughness of the surface of the solidified seal material. This may provide a simple and / or efficient gas evacuation. 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.

[0116] The surface roughness of the seal material may in embodiments be obtained as a result of a first pre-heating and pre-softening of the seal material that was provided in order to obtain the solidified seal material at the cover.

[0117] In one or more embodiments of the third aspect, said one or more gas passages may be provided as a consequence of a surface roughness of said surface part of the first glass sheet.

[0118] This may provide a simple and / or efficient gas evacuation. 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.

[0119] The surface roughness of said surface part of the first glass sheet may in embodiments be obtained as a result of cutting, such as laser cutting in the surface of the glass sheet. For example it may be a result of cutting a part of the through hole, such as a stepped portion of the through hole, in the glass sheet. In some embodiments this cutting may be done by means of a laser.

[0120] In one or more embodiments of the third aspect, wherein said one or more gas passages may be provided as a consequence of a combination of the surface roughness of the surface of the solidified seal material and the surface roughness of said surface part of the first glass sheet.

[0121] This may provide a simple and / or efficient gas evacuation. 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.

[0122] In one or more embodiments of the third aspect, the surface roughness of the surface of the solidified seal material which faces said surface part of the first glass sheet may be 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.

[0123] In one or more embodiments of the third aspect, the surface roughness of the surface of the solidified seal material which faces said surface part of the first glass sheet may be between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 80 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0124] In one or more embodiments of the third aspect, the surface roughness of the surface part of the first glass sheet which faces the solidified seal material may be 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.

[0125] In one or more embodiments of the third aspect, the surface roughness of the surface part of the first glass sheet which faces the solidified seal material is between 10 pm, and 150 pm, such as between 25 pm and 100 pm, such as between 35 pm and 80 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0126] In some embodiments of the present disclosure, the surface roughness of the surface part of the first glass sheet which faces the solidified seal material may 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 surface. This may e.g. enable enhanced bonding / connection and thus a stronger sealing.

[0127] 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. The surface roughness may e.g. be determined by means of a profilometer or a laser scanner. 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.

[0128] 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.

[0129] Surface roughness may be defined according to ISO 21920, such as ISO 21920-2.

[0130] In one or more embodiments of the third aspect, said surface roughness of the surface of the solidified seal material is obtained as a result of a pre-heating of the seal material of the cover so as to e.g. obtain binder burnout and / or a further softening of the solder amterial, and a subsequent pre-cooling of the softened seal material so as to solidify the seal material.

[0131] The surface roughness may at least partly also be caused by outgassing of the seal material, such as glass solder material, during the cover manufacturing.

[0132] In one or more embodiments of the third aspect, said pre-heating may comprise heating the glass solder material of the cover to a temperature above the rated glass transition temperature Tg of the glass solder material.

[0133] In one or more embodiments of the third aspect, said pre-heating may comprise heating the glass solder material of the cover to a temperature above the rated melting temperature Tm of the glass solder material.

[0134] In one or more embodiments of the third aspect, said surface roughness of the surface of the solidified seal material may be obtained as a result of a method of manufacturing the cover, wherein said method of manufacturing the cover is a method according to one or more of items 1-33 and / or according to the first aspect.

[0135] In one or more embodiments of the third aspect, said surface roughness of the seal 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 seal material surface which is unbonded to the surface of the covering body.

[0136] In one or more embodiments of the third aspect, said solidified seal 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. This may e.g. provide a more space saving and / or cost efficient solution .

[0137] In one or more embodiments of the third aspect, the heigh, such as the local maximum height, of the solidified seal material varies less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm over substantially the entire extent (22e) of the seal material.

[0138] 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.

[0139] In one or more embodiments of the third aspect, the surface roughness of the 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.

[0140] 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.

[0141] 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.

[0142] In one or more embodiments of the third aspect, the solidified seal material comprises or consist of a continuous ring of seal material, such as a continuous, annular ring of seal material. 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.

[0143] In one or more embodiments of the third aspect, the solidified seal material comprises or consist of a continuous ring of glass solder material, such as a continuous, annular ring of glass solder material.

[0144] In one or more embodiments of the third aspect, the solidified seal material, prior to said heating of the solidified seal material by means of said heater, 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.

[0145] This may e.g. enable easy arranging of the cover and seal material in one operation. It may also help to obtain an improved and / or more reliable sealing of the evacuated gap.

[0146] In one or more embodiments of the third 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. In some embodiments, said laser cutting may be conducted prior to or during assembling of the vacuum insulated glass unit assembly.

[0147] 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.

[0148] In one or more embodiments of the third aspect, the first glass sheet is a tempered glass sheet, such as a thermally tempered glass sheet, and wherein said laser cutting is provided prior to tempering of the first glass sheet. In one or more embodiments of the present disclosure, said provided cover, prior to said arranging of the cover, may have been subjected to:

[0149] - a heating of the glass solder material of the cover so as to e.g. outgas the seal material, and

[0150] - a cooling of the softened glass solder material so as to solidify the glass solder material.

[0151] In one or more embodiments of the third 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 seal material so as to soften the solidified seal material.

[0152] 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.

[0153] In one or more embodiments of the third aspect, said clamping force may be 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.

[0154] 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.

[0155] In one or more embodiments of the third aspect, the clamping force may directly or indirectly push the covering body so as to deform the softened seal material.

[0156] This may provide an improved seal of the evacuated gap and / or help to provide a less space consuming cover.

[0157] In one or more embodiments of the third 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. 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.

[0158] In one or more embodiments of the third aspect, the clamping part comprises a spring configured to provide said clamping force.

[0159] The spring may be advantageous as it may be reused and provide a consistent, desired force onto the cover.

[0160] Additionally or alternatively, in embodiments of the present disclosure, the clamping part may comprise a weight using gravity to provide the clamping force. In some embodiments, a combination of a spring and a weight may be used.

[0161] In one or more embodiments of the third 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.

[0162] 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.

[0163] In one or more embodiments of the third aspect, the clamping part may be arranged inside the evacuation cup, such as is attached directly or indirectly to a housing of the evacuation cup.

[0164] In one or more embodiments of the third aspect, said heating and softening of the peripheral edge seal material may be provided while the evacuation cup evacuates the gap, thereby providing a clamping of the peripheral edge seal material by means of a pressure difference between the gap and the exterior of the vacuum insulated glass unit assembly. This may e.g. provide an improved peripheral edge seal. It may additionally or alternatively provide an advantageous adaption of the thickness of the peripheral edge seal to the surface topography of the respective glass sheets, such as thermally tempered glass sheets. Thermally tempered glass sheets may be suffering from various surface variations, for example so called roller waves.

[0165] Said clamping of the peripheral edge seal may also be referred to as “Vacuum clamping”. Here pressure difference between the gap (that is evacuated) and the VIG unit assembly exterior may provide a force on the peripheral edge seal which may help to provide an improved sealing at the edge of the VIG unit.

[0166] In one or more embodiments of the third aspect, said heating of the solidified seal material of the cover so as to soften the solidified seal material to provide that the seal material adhere 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.

[0167] This may e.g. be advantageous from a manufacturing point of view.

[0168] In one or more embodiments of the third aspect, said radiation heater may comprise a laser, and wherein said heating beam is a laser beam.

[0169] 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.

[0170] In other embodiments, the radiation heating, such as infrared heating may heat the entire material of the cover.

[0171] In one or more embodiments of the third aspect, the second glass sheet is placed / located between the radiation heater and the seal material of the cover, so that the seal material of the cover is heated my means of a heating beam which is radiated through the second glass sheet. 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.

[0172] In one or more embodiments of the third aspect, said heating of the solidified seal material of the cover so as to soften the solidified seal material comprises heating to a temperature above the glass transition temperature of the seal material 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.

[0173] In one or more embodiments of the third 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. A step surface may be arranged between the larger diameter portion and the smaller diameter portion, and said arranging of the cover may comprise arranging the solidified seal 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.

[0174] The stepped through hole may be a countersunk hole.

[0175] 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.

[0176] 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. The step surface 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.

[0177] In one or more embodiments of the third aspect, the diameter of the larger diameter portion is at least 2 mm larger, such as at least 3 mm larger, than the diameter of the smaller diameter portion.

[0178] In one or more embodiments of the third aspect, the diameter of the larger diameter portion is between 5 mm and 12 mm, such as between 6 mm and 9 mm.

[0179] This may e.g. provide a space saving solution and / or a more visually pleasing solution.

[0180] 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.

[0181] 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.

[0182] In some embodiments of the present disclosure, the diameter of the smaller diameter portion may be less than 5 mm, such as less than 4 mm, such as less than 3 mm or less than 2 mm.

[0183] In one or more embodiments of the third aspect, the thickness of the covering body may be 2.5 mm or less, such as 1.5 mm or less, and / or wherein 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).

[0184] 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, and / or wherein 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 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.

[0185] In one or more embodiments of the third aspect, the depth, such as the maximum depth, of the larger diameter portion is between 0.05 mm and 0.35 mm larger, such as between 0.15 and 0.25 mm, larger than the thickness, such as the maximum thickness, of the covering body.

[0186] In one or more embodiments of the third aspect, 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, 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.

[0187] This may e.g. provide a more space-saving solution and / or a solution that is resistant.

[0188] In one or more embodiments of the third aspect, the first glass sheet and / or the second glass sheet has / have a thickness between 2 mm and 5 mm, such as between 3 mm and 4 mm and / or between 4 mm and 5 mm (both endpoints included).

[0189] 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, or at least 60% lower, than the thickness of the first glass sheet,

[0190] 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.

[0191] 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.

[0192] In one or more embodiments of the third aspect, the thickness of the covering body may be at least 5% lower, or at least 10% lower, than the depth (DE1) of the larger diameter portion. In one or more embodiments of the third aspect, wherein the thickness of the covering body may be 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.

[0193] In one or more embodiments of the third aspect, the thickness of the covering body may be 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.

[0194] In one or more embodiments of the third aspect, the method of manufacturing the vacuum insulated glass unit comprises laminating the vacuum insulated glass unit, wherein said lamination of the vacuum insulated glass unit comprises attaching a lamination glass sheet to the second major surface of the first glass sheet by means of a lamination interlayer so that the lamination glass sheet extends over and covers the cover and the through hole.

[0195] 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.

[0196] 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 second major surface of the first glass sheet.

[0197] In some embodiments of the present disclosure, the lamination interlayer may have a thickness of at least 0.4 mm, such as at least 0.6 mm, such as at least 0.7 mm.

[0198] In one or more embodiments of the third aspect, the covering body extend into the lamination interlayer.

[0199] 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. In some embodiments of the present disclosure, the surface of the covering body which faces away from the seal material is flush with or below the second surface of the first glass sheet after said cooling of the softened seal material so as to seal the evacuated gap.

[0200] 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

[0201] 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.

[0202] 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.

[0203] 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.

[0204] This may provide a stronger VIG unit and / or enable larger mutual distance between adjacent support structures in the evacuated gap. It may also allow use of thinner first and / or second glass sheets. This may e.g. improve heat insulation performance of the VIG unit and / or provide advantages in relation the aesthetics of the VIG unit.

[0205] 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.

[0206] In some embodiments of the third aspect, the covering body may comprise or consist of a structural glass body.

[0207] In other embodiments, the covering body may comprise or consist of a structural metal body.

[0208] In one or more embodiments of the third aspect, 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.

[0209] In one or more embodiments of the third aspect, the surface of the covering body which faces away from the gap and the sealing material may be arranged substantially flush with or below the second major surface of the first glass sheet.

[0210] In one or more embodiments of the third aspect, the providing of the cover comprises manufacturing the cover by means of a method according to any of items 1-33 and / or according to one or more embodiments of the first aspect described above.

[0211] In one or more embodiments of the third aspect, said providing of the cover comprises picking or ejecting, such as dropping, said cover comprising the covering body and the solidified seal material.

[0212] In one or more embodiments of the third aspect, the amount of binder material in the solidified seal material may be below 5 wt%, such as below 2 wt%, such as below 1 wt%

[0213] In one or more embodiments of the third aspect, the amount of solvent in the solidified seal material may be below 4 wt%, such as below 2 wt%, such as below 1 wt%, such as below 0.5 wt%. In one or more embodiments of the third aspect, said heating of the solidified seal material by means of a heater so as to soften the solidified seal material to provide that the softened seal material adhere to the surface part of the first glass sheet around the through hole may or may not provide a further reduction of the amount of binder material in the seal material of the cover when compared to the amount of binder material in the seal material before said heating by means of the heater.

[0214] In one or more embodiments of the third aspect, the heigh, such as local maximum height, of the solidified seal material vary less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm or less than 0.01 mm over the entire longitudinal extent of the seal material of the cover.

[0215] In some embodiments, the amount (wt%) of binder material in the seal material before it has been heated by the heater and solidified by cooling it (during manufacturing of the cover) may be higher than the amount (wt%) of binder material in the seal material after it has been heated by the heater and solidified by cooling it.

[0216] In some embodiments, the amount (wt%) of binder material in the seal material before it has been heated by the heater and solidified by cooling it to seal the hole and thereby seal the evacuated gap may be higher than the amount (wt%) of binder material in the seal material after it has been heated by the heater and solidified by cooling it to seal the evacuated gap.

[0217] In some embodiments, the amount (wt%) of solvent material in the seal material before it has been heated by the heater and solidified by cooling it (during manufacturing of the cover) may be higher than the amount (wt%) of solvent material in the seal material after it has been heated by the heater and solidified by cooling it.

[0218] In some embodiments, the amount (wt%) of solvent material in the seal material before it has been heated by the heater and solidified by cooling it to seal the hole and thereby seal the evacuated gap may be higher than the amount (wt%) of solvent material in the seal material after it has been heated by the heater and solidified by cooling it to seal the evacuated gap. The present disclosure additionally relates, in a fourth aspect, to a cover, wherein the cover comprises a covering body and a solidified seal material arranged on the covering body. In some embodiments of the present disclosure, the cover may be a cover obtained by means of a method according to any of items 1-33 and / or 96-101. In some embodiments, the cover may be a cover obtained by means of a method according to one or more embodiments of the first aspect.

[0219] In some embodiments of the fourth aspect, the surface roughness of the surface of the solidified seal material which faces away from the covering body may be above 10 pm, such as above 25 pm, such as above 35 pm. In some embodiments of the present disclosure, the surface roughness of the surface of the solidified seal material which faces away from the covering body 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 some embodiments, said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

[0220] In some embodiments of the fourth aspect, the surface roughness of the 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, such as substantially randomly, across the surface of the glass solder material.

[0221] In some embodiments of the fourth aspect, the solidified glass solder material comprises or consist of a continuous ring of glass solder material, such as a continuous, annular ring of glass solder material.

[0222] In some embodiments of the fourth aspect, the solidified seal material comprises a substantially continuous layer of solidified glass solder material, such as wherein the glass solder material covers at least 50%, such as at least 70%, such as at least 90% of the surface of the covering body.

[0223] In some embodiments of the fourth aspect, the solidified seal 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. In some embodiments of the fourth aspect, the height, such as local maximum height, of the solidified seal material varies less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm over the entire extent of the seal material.

[0224] In some embodiments of the fourth aspect, the amount of binder material in the solidified seal material is below 5 wt%, such as below 2 wt%, such as below 1 wt% and / or 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%, such as below 0.2 wt%.

[0225] The present disclosure moreover relates, in a fifth 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:

[0226] - 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,

[0227] - arranging the workpiece in a working space,

[0228] - heating the seal material in the working space to a target temperature by means of a heater,

[0229] - cooling the covering body workpiece and seal material so as to solidify the seal material,

[0230] - 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.

[0231] 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.

[0232] In some embodiments of the fifth aspect, the seal material may comprise a glass solder material.

[0233] In one or more embodiments of the fifth aspect, wherein 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.

[0234] In one or more embodiments of the fifth 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 (22).

[0235] 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.

[0236] In one or more embodiments of the fifth 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.

[0237] In one or more embodiments of the fifth 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.

[0238] In one or more embodiments of the fifth 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.

[0239] 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.

[0240] 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 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.

[0241] This may e.g. enable an advantageous gas evacuation when the cover is used for sealing an evacuated VIG unit gap.

[0242] 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.

[0243] 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.

[0244] In one or more embodiments of the fifth aspect, the covering body is made from metal or glass, such as annealed glass.

[0245] 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.

[0246] The method of manufacturing the VIG unit may in some embodiments include the step of collecting an obtained cover from a controlled, such as reduced, such as sealed, atmosphere environment of a container in which it has been stored until use of it, such as wherein the collected cover is placed so as to cover the through hole and so that the solidified solder material is configured to be heated by a heater to seal the gap when the gap of the VIG unit assembly has been evacuated to a desired pressure.

[0247] In one or more embodiments of the third aspect, said provided cover may be a cover obtained by means of a method described herein.

[0248] The present disclosure moreover relates, in a sixth 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:

[0249] - 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,

[0250] - 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.

[0251] This may e.g. provide a more cost efficient and / or fast manufacturing method.

[0252] In some embodiments of the sixth aspect, the seal material at the covering body workpiece comprises a glass solder material.

[0253] In some embodiments of the sixth aspect, the seal material at the covering body workpiece is a solidified seal material.

[0254] In some embodiments of the sixth 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.

[0255] In some embodiments of the sixth 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.

[0256] In some embodiments of the sixth 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.

[0257] In some embodiments of the sixth 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.

[0258] In one or more embodiments of the present disclosure regarding the method of manufacturing a cover for sealing a VIG unit as previously described, said heating of the seal material comprises one or more controlled temperature holding periods, such as constant temperature holding periods, between the time of initiating the heating and time of reaching the target temperature. 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.

[0259] In one or more embodiments of the present disclosure, 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. 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.

[0260] In one or more embodiments of the present disclosure, the heat increase rate, such as heating gradient, is decreased as the temperature of the seal material is increased. 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.

[0261] In one or more embodiments of the present disclosure, 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. 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.

[0262] 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.

[0263] 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. 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.

[0264] In one or more embodiments of the present disclosure, heating of the seal material during the heating time, 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.

[0265] 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.

[0266] In one or more embodiments of the present disclosure, the controlled 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. Additionally or alternatively, 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. Additionally or alternatively, 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.

[0267] 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.

[0268] 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 seal 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.

[0269] In one or more embodiments of the present disclosure, the one or more covering body workpieces are in a reduced atmosphere during the binder burnout temperature holding period. 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.

[0270] In one or more embodiments of the present disclosure, the one or more covering body workpieces are at atmospheric pressure during the binder burnout temperature holding period. 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.

[0271] The target temperature may be in the range of 300 - 500 °C, such as in the range of 350 - 450 °C, such as in the range of 370 - 400 °C. Additionally or alternatively, the target temperature may be at least 300 °C, such as at least 350 °C, such as at least 370 °C. Additionally or alternatively, the target temperature may be less than 500 °C, such as less than 450 °C, such as less than 400 °C.

[0272] In one or more embodiments of the present disclosure, cooling of the one or more heated covering body workpieces and seal material comprises a controlled, such as constant, cooling temperature holding period. 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.

[0273] In one or more embodiments of the present disclosure, 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. Additionally or alternatively, 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. Additionally or alternatively, 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.

[0274] The cooling temperature may be in the range of 200 - 350 °C, such as in the range of 250 - 325 °C, such as in the range of 280 - 310 °C. Additionally or alternatively, the cooling temperature may be at least 200 °C, such as at least 250 °C, such as at least 280 °C. Additionally or alternatively, the cooling temperature may less than 350 °C, such as less than 325 °C, such as less than 310 °C. A prolonged cooling temperature holding period may be favorable in order to provide an improved seal material, such as substantially stress-free, solidified seal 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.

[0275] In one or more embodiments of the present disclosure, the one or more covering body workpieces are in a reduced atmospheric pressure during the controlled, such as constant, cooling temperature holding period. A reduced atmosphere may provide a favorable surface chemistry / 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.

[0276] In one or more embodiments of the present disclosure, the one or more covering body workpieces are at atmospheric pressure during the controlled, such as constant, cooling temperature holding period. 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.

[0277] In one or more embodiments of the present disclosure, heating of the seal 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 ozone, and / or to an inactive gas, such as a noble gas. 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.

[0278] 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.

[0279] In one or more embodiments of the present disclosure, 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. Such protrusions may provide a simple means of centring 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 centring effect of the covering body. Protrusions may favorably be provided at locations not corresponding to channels in the solidified seal material if such exist.

[0280] 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 seal 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.

[0281] The gaps are understood to e.g. stretch across the entire height of the covering body between major surfaces thereof.

[0282] In one or more embodiments of the present disclosure, the step of obtaining one or more covers comprises providing three or more protrusions in the side surface of the covering body. Three or more protrusions may provide a centring effect across the entire perimeter of the covering body. Additionally, it may leave sufficient space for more effective evacuation between the protrusions.

[0283] In one or more embodiments of the present disclosure, the step of obtaining one or more covers comprises providing three or more gaps in the side surface of the covering body. In one or more embodiments of the present disclosure, the 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. Equidistant protrusions may provide a centring effect in all lateral directions. 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.

[0284] In one or more embodiments of the present disclosure, the covering body of each 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. This design of the covering body provides an alternative to a circular shape with protrusions and / or gaps cut out of I into, respectively. In order to be suitable, a polygon-shaped 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.

[0285] In one or more embodiments of the present disclosure, the polygon has at least five vertices, such as at least six vertices, such as at least seven vertices. The larger the number of vertices, the more does the polygon approximate a circle. A balance must be found between efficient evacuation and strong sealing. The efficient evacuation may be partially provided by the difference in radial distance to a vertex and an edge (difference between protrusion and gap). Meanwhile, a sufficiently strong seal may be provided by selecting a polygonal shape with a large enough inscribed circle such that the overlap of the covering body and the floor of the larger diameter (recessed) portion of the through hole is sufficient also at the edges of the polygon. If this overlap is too short, for example if the polygonal shape only contains a few vertices such that the difference in radial distance is large between a vertex and an edge, the seal may suffer from stresses and / or may crack at these points of narrow seal. In one or more embodiments of the present disclosure, each protrusion and / or each gap in the side surface of the covering body has a semicircular cross section. If the covering bodies are 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.

[0286] Alternatively, the protrusions and / or gaps may be elliptical, polygonal, and / or irregularly shaped.

[0287] In one or more embodiments of the present disclosure, 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, and / or wherein 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. 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.

[0288] 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 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 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.

[0289] 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.

[0290] 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 the the floor of a larger diameter portion of the through hole, such as between solidified seal 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.

[0291] 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 space between a side surface of the covering body and a side surface (10bs) of the larger diameter portion, wherein said space has a total area as seen from above of at least 4.0 mm2, such as at least 6.0 mm2, such as at least 10.0 mm2. 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 space between a side surface of the covering body and a side surface of the larger diameter portion, wherein said space has a total area as seen from above of at least 50%, such as at least 75%, such as at least 90% of the area of the smaller diameter portion of the through hole.

[0292] A sufficiently large non-overlapping space of the covering body and the larger diameter portion of the through hole may provide a more efficient evacuation, as it may provide a good vertical evacuation passage around the covering body. In order to balance and optimize the evacuation, this non-overlapping space may be selected based on the cross-sectional area of the smaller diameter portion of the through hole. In one or more embodiments of the present disclosure, the step of evacuating the gap of the vacuum insulated glass (VIG) unit assembly proceeds with a gas extraction rate of at least 0.05 L / s, such as at least 0.06 L / s, such as at least 0.07 L / s.

[0293] It is understood that in some embodiments the average flow resistance from the gap 6 to the ambient environment, such as the interior of an evacuation cup, when determined in seconds per liter (s / L) evacuated gas, may be less than 30 s / L, such as less than 20 s / L, such as less than 18 s / L. In some embodiments, the average flow resistance from the gap 6 to the ambient environment, such as the interior of an evacuation cup, when determined in seconds per liter evacuated gas, may be between 2 s / L and 30 s / L, such as between 4 and 25 s / L, such as between 6 and 20 s / L. A larger gas extraction rate corresponds to a faster evacuation of a given volume. Since VIG units for building windows and / or refrigerator doors may be relatively large, a correspondingly large volume of gas must be extracted from the gap between the two glass sheets. Therefore, it may be advantageous to provide an evacuation pathway with a suitably low resistance and thereby a relatively high gas extraction rate with a reduced physical footprint of the cover and through hole.

[0294] In one or more embodiments of the present disclosure, the step of heating the solidified seal material comprises raster scanning a laser beam across the surface of the solidified solder material that faces away from the covering body. 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. 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 the solidified seal material that is opposite the glass sheet of the covering body.

[0295] In one or more embodiments of the present disclosure, the 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. 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.

[0296] 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.

[0297] In one or more embodiments of the present disclosure, the 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. 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.

[0298] 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. 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. Another aspect of the present disclosure is a cover, wherein a primer layer, such as a single primer layer or a multilayer primer layer, is arranged as part of the seal layer up against the covering body. Additional layers of the seal layer may be arranged on top of the primer layer. 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.

[0299] It is understood that in other embodiments, the seal at the cover may not comprise (a) primer(s). As described in more details further below, 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.

[0300] In one or more embodiments, the primer layer is arranged so as to cover substantially the whole major surface of the covering body. 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. 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. 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.

[0301] In one or more embodiments, the primer layer is arranged so as to cover the same area of the major surface of the covering body as is covered by the seal material.

[0302] In one or more embodiments, the primer layer is arranged so as to cover the whole major surface of the covering body except a center area, such as wherein the primer layer forms a ring around the center area. For example, the primer layer may in some embodiments be arranged across substantially the entire major surface of the covering body. 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. 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.

[0303] 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. A plurality of covers can then 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.

[0304] 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. 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.

[0305] 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.

[0306] In one or more embodiments, the primer layer comprises a material with a softening temperature, such as the Littleton softening temperature that is lower than the softening temperature, such as the Littleton softening temperature, of the covering body and higher than the softening temperature, such as the Littleton softening temperature, of the seal material.

[0307] 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.

[0308] 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.

[0309] An additional aspect of the present disclosure is a cover as previously described, wherein solidified seal material is substantially non-crystalline, such as wherein the crystallinity is less than 30%, such as less than 20%, such as less then 10%.

[0310] Crystalline grains and / or regions in the seal material may increase the brittleness of the material and thereby reduce the strength of the seal. Crystallization may occur if the seal material is heated to too high temperatures. Most common seal materials are predominantly amorphous such that short-range order may be present without any long-range order. This may reduce the risk of the material cracking and / or shifting along a crystalline direction and / or a grain boundary. In one or more embodiments of the present disclosure, the solidified seal material comprises or consists of a low-temperature glass solder material. Choosing a low- temperature glass solder material for the seal material may provide a solution where the temperatures necessary to sinter and / or soften the material are lower. This may provide a more energy efficient manufacturing process and hence a more environmentally friendly production. Additionally or alternatively, choosing a low- temperature glass solder material may enable the through hole to be sealed without increasing the temperature to a range where a thermally tempered first glass sheet would lose its tempering.

[0311] In one or more embodiments of the present disclosure, the 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. These oxides may be known in various combinations as low-temperature solder glass materials.

[0312] In one or more embodiments of the present disclosure, the solidified solder 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, TeCh, and / or TesCL.

[0313] 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. 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 de-temper. 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.

[0314] In one or more embodiments of the present disclosure, the Te / V-based solder material additionally comprises one or more of AI2O3, SiC>2, MgO, P2O5, Bi20s, 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. 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. In one or more embodiments of the present disclosure, the solder material comprises Bi2C>3 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.

[0315] 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.

[0316] 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.

[0317] 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. 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.

[0318] 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.

[0319] 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.

[0320] 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. 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] 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. 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 detempering 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.

[0326] 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. 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.

[0327] 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.

[0328] In one or more embodiments of the present disclosure, one or both of the one or two primer layers comprises one or more inorganic oxides, such as at least 50 wt-% of one or more inorganic oxides.

[0329] 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.

[0330] In one or more embodiments of the present disclosure, each of the one or two primers, comprises Bi, such as Bi2Oa. 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-% Bi2Oa. In one or more embodiments of the present disclosure, one or both of the one or two primer layers comprise Bi20s in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0331] 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.

[0332] 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-%. 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.

[0333] 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.

[0334] 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. 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.

[0335] 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.

[0336] 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.

[0337] According to one or more embodiments of the present disclosure, one or both primer layers 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 the glass sheet at a temperature above the glass transition temperature of both the primer layer material and the glass of the glass sheet. This may e.g. be done during a thermal tempering process for thermally tempering the glass sheets prior to assembling the glass sheet assembly. 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.

[0338] 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 the one or more laser light beams (e.g. in combination with the 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.

[0339] 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.

[0340] 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 / covering body.

[0341] 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. 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.

[0342] 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.

[0343] 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.

[0344] 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.

[0345] 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.

[0346] 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.

[0347] 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. It is generally understood that the solder material types mentioned above may be used for the seal material of the cover and / or for the edge seal material that encloses the evacuated gap.

[0348] It is generally understood that the solder material used at the edge seal may or may not comprise one or more single layer or multi-layer primer layers. An 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

[0349] • 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

[0350] • comprise Bi2Os, e.g. in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0351] 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 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.

[0352] It is understood that the temperatures such as glass transition temperature, Littleton temperature and / or the like mentioned above may also or may not apply for the edge serai material, such as the above mentioned edge seal material, of the edge seal.

[0353] It is however understood that in other embodiments, the edge seal may comprise edge seal solder material without the use of one or more primers.

[0354] In one or more embodiments of the present disclosure, the heating of the seal material comprises controlling the gradient of the heating of the solder material so that the gradient is controlled to decrease between the initiation of the heating and the time when the target temperature is reached.

[0355] In one or more embodiments of the present disclosure, the gradient of the heating of the solder is controlled to decrease after a binder burnout temperature has been reached.

[0356] In one or more embodiments of the present disclosure, the method of manufacturing a cover for a VIG unit comprises shaping the solidified seal by means of a shaping tool.

[0357] An additional aspect of the present disclosure is 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:

[0358] • 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,

[0359] • arranging the one or more covering body workpieces in a working space,

[0360] • heating the seal material in the working space to a target temperature (Tar21) by means of a heater, wherein said heating is provided so as to provide an outgassing of the glass solder material,

[0361] • cooling the one or more heated covering body workpieces and seal material so as to solidify the seal material,

[0362] • obtaining one or more covers from the one or more cooled covering body workpieces, wherein the method comprises shaping the solidified seal by means of a shaping tool.

[0363] 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.

[0364] 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.

[0365] In one or more embodiments of the present disclosure, 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 seal material that faces away from the covering body workpiece or covering body. 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.

[0366] In one or more embodiments of the present disclosure, 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 cooled covering body workpieces.

[0367] In one or more embodiments of the present disclosure, 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. 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. 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.

[0368] In one or more embodiments of the present disclosure, 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. 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. 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.

[0369] In one or more embodiments of the present disclosure, 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 seal material. 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.

[0370] In one or more embodiments of the present disclosure, said shaping of the solidified seal material comprises modifying the surface roughness, such as by means of polishing. 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 seal material in addition to any evacuation channels. By manipulating the surface roughness, the direction of the air flow during evacuation can be controlled.

[0371] In one or more embodiments of the present disclosure, said shaping of the solidified seal comprises increasing the surface roughness of the solidified seal material so as to provide a surface roughness in order to reduce the flow resistance when the solidified seal 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 (predefined) 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. 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.

[0372] In one or more embodiments of the present disclosure, said shaping of the solidified seal comprises shaping the solidified seal material so as to reduce the flow resistance when the solidified seal 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.

[0373] In one or more embodiments of the present disclosure, 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.

[0374] In one or more embodiments of the present disclosure, said 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.

[0375] In one or more embodiments of the present disclosure, 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. In one or more embodiments of the present disclosure, the step of comparing each covering body 21 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.

[0376] 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. 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. Alternatively, the cover(s) may be arranged in an atmosphere comprising or containing a gas that reduces contamination of the cover.

[0377] In one or more embodiments of the present disclosure, the controlled, such as reduced atmosphere environment comprises a desiccator. 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.

[0378] In one or more embodiments of the present disclosure, the reduced atmosphere environment 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. Description of the drawings

[0379] The present disclosure will in the following be described in greater detail with reference to the accompanying drawings:

[0380] Fig. 1 illustrates a schematic view of a VIG unit assembly and a cover, according to various embodiments of the present disclosure,

[0381] Fig. 2 illustrates a schematic view of VIG unit manufacturing, according to various embodiments of the present disclosure,

[0382] 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,

[0383] 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,

[0384] Figs. 4a-4b illustrates schematically a cover according to various embodiments of the present disclosure,

[0385] Fig. 5 illustrates schematically a VIG unit according to various embodiments of the present disclosure,

[0386] Fig. 6 illustrates schematically a laminated VIG unit according to various embodiments of the present disclosure,

[0387] 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,

[0388] 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,

[0389] Fig. 9 illustrates schematically a VIG unit according to various embodiments of the present disclosure,

[0390] 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, 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,

[0391] Fig. 11 illustrates schematically manufacturing of a through hole, according to embodiments of the present disclosure,

[0392] 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,

[0393] Fig. 13 illustrates schematically manufacturing of a plurality of covers in a working space, according to embodiments of the present disclosure,

[0394] Fig. 14 illustrates schematically heating of covers during cover manufacturing, according to various embodiments of the present disclosure,

[0395] Fig. 15 illustrates schematically a flow chart relating to VIG unit manufacturing, according to embodiments of the present disclosure,

[0396] 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,

[0397] Fig. 17 Fig. illustrates schematically evacuation of a gap, where gas leaves through a gas passage, according to embodiments of the present disclosure,

[0398] 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,

[0399] Figs. 19A-

[0400] 19E illustrate grayscale images of a successful test of using a cover with the solidified seal material, according to embodiments of the present disclosure,

[0401] Figs. 20A-

[0402] 20B illustrate microscopic images of a test of a step surface, according to embodiments of the present disclosure,

[0403] 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, Fig. 22 illustrates a manufacturing of a vacuum insulated glass (VIG) unit, according to further embodiments of the present disclosure,

[0404] Fig. 22a illustrates a pushing body according to embodiments of the present disclosure,

[0405] Figs. 23A-

[0406] 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,

[0407] 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,

[0408] Figs. 27A-

[0409] 27B : illustrate heat profiles for manufacturing covering body workpieces according to various embodiments of the present disclosure, Fig. 28A-

[0410] 31 : illustrate top and / or bottom view of covering bodies with protrusions and / or gaps according to embodiments of the present disclosure,

[0411] Fig. 32 : illustrates a system for shaping of solidified seal material according to embodiments of the present disclosure,

[0412] Fig. 33: : illustrates a cover with a seal according to embodiments of the present disclosure,

[0413] Fig. 34A-

[0414] 35B : illustrate cross sections I side views of covers according to embodiments of the present disclosure, Fig. 36 : illustrates a cover with a primer layer according to embodiments of the present disclosure,

[0415] Fig. 37 : illustrates a cross section of a through hole of a VIG unit with a cover according to embodiments of the present disclosure,

[0416] Figs. 38A-

[0417] 38D : illustrate top views of primer layers according to embodiments of the present disclosure, and

[0418] Fig. 39 : illustrates a cross section of a through hole with a cover according to embodiments of the present disclosure, and

[0419] Fig. 40 : illustrates a laser raster pattern used for heating the seal material and seal the gap according to embodiments of the present disclosure.

[0420] Description

[0421] 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.

[0422] 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.

[0423] 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.

[0424] 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 .

[0425] 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.

[0426] 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.

[0427] 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.

[0428] A step surface 10s is arranged between the larger diameter portion 10b and the smaller diameter portion 10a.

[0429] 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. 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.

[0430] 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.

[0431] 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.

[0432] 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.

[0433] 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.

[0434] The covering body 21 may comprise or consist of a structural body such as a structural glass body or a structural metal body.

[0435] 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.

[0436] 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

[0437] 21 hereby covers at least a part 10a of the through hole 10.

[0438] In fig. 1, The arranging of the cover 20 comprises arranging the solidified seal material

[0439] 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.

[0440] 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.

[0441] 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. 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.

[0442] 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.

[0443] 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.

[0444] 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] 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.

[0449] 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.

[0450] 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.

[0451] 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.

[0452] 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.

[0453] 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.

[0454] 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.

[0455] 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.

[0456] 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. 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.

[0457] 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.

[0458] 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.

[0459] 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.

[0460] Further embodiments comprising using a clamping part / pushing part 40 are illustrated in figs. 22-23D, which are described in more details further below.

[0461] 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. 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.

[0462] 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.

[0463] 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.

[0464] 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.

[0465] 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.

[0466] 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. 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.

[0467] 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.

[0468] 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.

[0469] 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.

[0470] 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 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. 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.

[0471] 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.

[0472] 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.

[0473] 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.

[0474] 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. 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.

[0475] As illustrated in fig. 4, the solidified seal 22 material may encompasses 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.

[0476] 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.

[0477] 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.

[0478] 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.

[0479] 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.

[0480] 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.

[0481] 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.

[0482] 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.

[0483] 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.

[0484] 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.

[0485] 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.

[0486] The lamination interlayer 8a may comprise or be one or more of the following::

[0487] • ethylene vinyl acetate (EVA), • polyisobutylene (PIB),

[0488] • polyacetals such as polyvinyl butyral (PVB),

[0489] • transparent polyurethane (Pll),

[0490] • thermoplastic polyurethane (TPU),

[0491] • polyvinyl chloride (PVC),

[0492] • polyesters,

[0493] • cyclo olefin polymers (COP),

[0494] • ionomers and / or an adhesive configured to be activated by ultraviolet radiation.

[0495] PVB, EVA or TPU may however be preferred as the lamination interlayer 8.

[0496] 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.

[0497] 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.

[0498] 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.

[0499] 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.

[0500] 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.

[0501] 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.

[0502] 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.

[0503] 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.

[0504] 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.

[0505] Fig. 9 illustrates schematically a cross section of a VIG unit 100 according to various embodiments of the present disclosure.

[0506] 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.

[0507] 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.

[0508] 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.

[0509] 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.

[0510] 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.

[0511] 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.

[0512] 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,

[0513] 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. 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.

[0514] 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.

[0515] 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.

[0516] 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.

[0517] 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.

[0518] 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.

[0519] 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.

[0520] The first glass sheet 2 and the second glass sheet 3 may have the same or different thickness TH1. 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.

[0521] 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.

[0522] 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.

[0523] 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.

[0524] 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.

[0525] 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.

[0526] 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.

[0527] The seal material 22 may hence adhere to both the surfaces 21a, 10s, and moreover to the surfaces 21c, 10bs.

[0528] 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.

[0529] 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.

[0530] 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.

[0531] 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.

[0532] 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.

[0533] 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. 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.

[0534] 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.

[0535] 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 .

[0536] 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.

[0537] 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.

[0538] 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 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.

[0539] See also the previous description relating to surface roughness of the first glass sheet 2 surface and the seal material 22 surface 22a roughness. 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.

[0540] 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.

[0541] 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.

[0542] 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.

[0543] 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.

[0544] 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. 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.

[0545] 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.

[0546] 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.

[0547] 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.

[0548] 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.

[0549] 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. The heating / fi ring 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.

[0550] 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.

[0551] 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.

[0552] 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.

[0553] 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).

[0554] 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.

[0555] 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.

[0556] 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.

[0557] 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.

[0558] 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.

[0559] 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.

[0560] 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.

[0561] 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.

[0562] The plurality of covering bodies 21 may be placed on a base 95 in the vacuum chamber 50.

[0563] In some embodiments, the heater 60 comprises a radiation heater, such as a laser.

[0564] 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.

[0565] 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.

[0566] 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.

[0567] 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.

[0568] 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.

[0569] 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.

[0570] 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. 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.

[0571] 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.

[0572] 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.

[0573] 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.

[0574] 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. 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.

[0575] 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.

[0576] 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.

[0577] This heat increase rate may in some embodiments of the present disclosure be conducted over at least 20% of the total heating time Ht21.

[0578] 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.

[0579] 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.

[0580] 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.

[0581] 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. 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.

[0582] 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.

[0583] 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.

[0584] 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.

[0585] 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.

[0586] 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.

[0587] 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.

[0588] 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. 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.

[0589] 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.

[0590] 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%.

[0591] 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%.

[0592] 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.

[0593] 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%.

[0594] 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%.

[0595] 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. 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.

[0596] 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.

[0597] 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.

[0598] 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.

[0599] 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.

[0600] 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%. 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.

[0601] 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.

[0602] 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.

[0603] 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.

[0604] 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.

[0605] 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.

[0606] 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.

[0607] 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.

[0608] Finally, the softened seal material 22 and the VIG unit is cooled in Step S156 to provide the final VIG unit.

[0609] 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.

[0610] 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.

[0611] In Step S161 , workpieces for use as covering body 21 are provided. It may e.g. be glass body workpieces or metal body workpieces.

[0612] 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.

[0613] 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). 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.

[0614] 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.

[0615] 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.

[0616] 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.

[0617] 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.

[0618] 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.

[0619] 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. 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.

[0620] 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.

[0621] 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.

[0622] 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.

[0623] Even though not shown in fig. 18, the solidified seal material 22 may comprise a continuous ring of solidified seal material 22, in this case an annular ring of seal material. The seal material 22 surface 22a roughness is obtained by means of preheating and subsequent cooling of the seal material 22 as e.g. described according to various embodiments above and / or below. Figs. 19A-19E illustrates grayscale images of a successful test of using the cover 20 illustrated in fig. 17 with the solidified seal material 22. The images in figs. 19A-19E are taken to provide a view through the glass sheet 3 (see fig. 1) opposite the hole 10.

[0624] In fig. 19A, the cover 20 has been arranged on a glass sheet, and no heating has been provided yet to a degree where the seal material 22 softens. As can be seen in the figures 19B-19E, the seal material 22 gradually turns darker. The darkening indicates that the seal material is heated to soften and adhere to the step surface 10s around the smaller diameter hole 10a. This may e.g. be obtained by means of laser heating or the like, see e.g. fig. 2 which is described above.

[0625] In fig. 19B it can be seen that a smaller dark area is formed (enclosed by dashed lines to improve understanding). As the heating and softening gradually evolves (see gradually evolving in figs. 19->19-> 19-> 19E), it can be seen that continuously larger areas AR1 of the seal material bonds to the step surface 10s, since the darkened area increases. In the figures 18B-18E, the dark area AR1 is encircled by dashed lines for improved understanding - the dashed lines are white to improve contrast and readability. In fig. 18E, the seal material 22 fully adhere to the step surface continuously around the smaller diameter hole and encircles the smaller diameter hole. Hence, a full, hermetic, airtight connection is formed when the seal material 22 is cooled again.

[0626] Fig. 20A-20B illustrates microscopic images of the step surface 10s according to a test. The surface 10s roughness may be obtained by a laser cutting into the surface of the glass sheet 2, see e.g. the description above in relation to fig. 11. A surface roughness parameter of a part of the step surface 10s that is later to bond with the seal material 22 of the cover is in fig. 20B measured to be 72 pm. This laser roughness may be adapted by proper control of the laser, by selecting a suitable size laser and / or by surface treatment after the laser cutting.

[0627] Fig. 21 illustrates microscopic images of a test sample comprising the glass sheet 2 with the stepped through hole 10 which is covered by the cover 20. The hole 10 comprises the smaller diameter portion 10a and the larger diameter portion 10b. The covering body 21 comprises the surface 21a which faces the step surface 10s. The seal material 22, in this case a glass frit material, is placed between the covering body surface 21a and the glass sheet 2 surface 10s. As can be seen, the covering body 21 surface 21a is smooth, whereas the step surface 10s of the glass sheet 2 facing the seal material 22 is rough and comprises a surface roughness as e.g. described above.

[0628] The seal material 22 has been subjected to the heating and softening by means of a heater 7, such as a radiation heater, such as a laser or an infrared heater (see e.g. fig. 2), and thus, any initial surface roughness of the seal material 22 that may have resulted in a gas passage for gas that is evacuated from the gap of the VIG unit has been removed, and the shape and size seal material 22 has been adapted due to the heating and under influence of a clamping part 40 (see fig. 2) so as to also bond to the surface step 10s. As can be seen in the enlarged rectangle of the image, the seal material 22 extends to abut and bond well to the step surface 10s. The seal material 22 hence provides an airtight hermetic seal between the covering body 21 and the glass sheet 2.

[0629] Fig. 22 illustrates schematically a manufacturing of a vacuum insulated glass (VIG) unit by means of a VIG unit assembly 1 , according to further embodiments of the present disclosure. As also illustrated in fig. 2, a clamping part / pushing part 40 may be arranged inside the evacuation cup 9. The clamping part 40 may or may not be attached directly or indirectly to the housing 9b of the evacuation cup 9. The evacuation cup 9 may provide a counter force so that the clamping part 40 can provide the clamping force / pushing 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 provide the force F 1.

[0630] 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 70 pushes 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. In fig. 22, an intermediate pushing body 42 is used. The intermediate pushing body 42 is arranged between the force F1 inducing clamping part 40 and the covering body 21 surface 21b.

[0631] The maximum width, such as the maximum diameter, of the intermediate pushing body 42 is larger than the maximum width (See D3 of fig. 9) of the covering body 21 , and is larger than the maximum width (such as the maximum diameter, see D1 in fig. 9) of the evacuation hole 10. A surface 42a of the intermediate pushing body 42 faces and presses towards the covering body 21. The intermediate pushing body 42 transfers the pushing force F1 to the covering body 21. The heater 7, such as radiation heater, such as a laser, heats the solidified seal material 22 to soften it. When the seal material 22 has softened and is thus not more solidified, the intermediate pushing body 42 transfers the force F1 from the clamping / pushing part 40 and thereby presses the covering body 21 further into the larger diameter portion 10b of the hole 10.

[0632] At some point, in some embodiments of the present disclosure, the pushing body 42 is displaced so that the surface 42a of the pushing body 42 reaches the major surface 2b of the glass sheet 2. This acts as a mechanical stop and prevents the pushing body 42 from pushing the covering body 21 further into the hole. In the embodiment illustrated in fig. 22, the pushing body 42 surface 42a is substantially plane and will provide that the surface 21b of the covering body 21 may be substantially flush with the glass sheet 2 surface 2b when the seal material 22 has been cooled.

[0633] In some embodiments of the present disclosure, gas evacuation channels 43 may be provided, such as cut or milled, into the surface 42a of the pushing body 42, see also fig. 22a. These channels 43 may provide predetermined gas GA flow paths also when the seal material 22 has been softened and the body 42 rests on the glass sheet surface 2b.

[0634] In some embodiments of the present disclosure, the clamping part 40 may be arranged opposite the evacuation hole 10, as e.g. illustrated in figs 2 and 22. In other embodiments (not illustrated), the clamping part 40 may be arranged at another location, such as opposite the glass sheet 2 surface 2b, and the pushing body 42 may be placed between the clamping part I pushing part 40 and the glass sheet 2 surface 2b. It is generally understood that even though gaskets are not shown in figs. 2 and 22, it is understood that one or more gaskets 9x, such as e.g. annular gaskets, may be arranged between the evacuation cup 9 and the glass sheet 2 surface 2b in order to provide a tightening between the cup 9 body and the glass sheet 2.

[0635] Fig. 22a illustrates schematically a pushing body 42 according to embodiments of the present disclosure. The pushing body 42 may be used during VIG unit manufacturing as e.g. described above in relation to e.g. fig. 2 and / or 22. The view is towards the pushing surface 42a of the pushing body 42 that is configured to push the covering body 21. Predefined gas evacuation channels 43 are be provided in the surface 42a of the pushing body 42. The evacuation channels 43 may be obtained e.g. during manufacturing of the pushing body 42, such as by means of cutting, casting, machining, milling and / or the like. These evacuation channels 43 may provide predetermined gas GA flow paths also when the seal material 22 has been softened and the body 42 rests on the glass sheet surface 2b.

[0636] In fig. 22a, the surface 42a comprises six predefined channels that extends radially from the center of the pushing body 42. It is naturally under stood that in some embodiments, fewer than six or more than six channels 43 may be provided, such as between one channel 43 and sixteen channels, such as between two channels 43 and eight channels, such as between two channels and six channels, endpoints included.

[0637] The channels 43 may as illustrated extend to the outer boundary 42x of the pushing body 42 so that gas can enter through the side.

[0638] In other embodiments of the present disclosure (not illustrated), instead of the predefined channels 43, or in addition to the predefined channels 43, a surface roughness may be provided in at least a part of the surface 42a. This surface roughness may or may not be larger than the surface roughness of the covering body surface 21b and / or the surface roughness of the glass sheet 2 surface 2b. The surface roughness of the surface 42a which is configured to be arranged to face the covering body 21 surface 21b may be between 10 pm and 250 pm such as between 25 pm and 150 pm, such as between 45 pm and 100 pm. Said surface roughness may be the Ra or Rz surface roughness parameter, preferably the Ra parameter. The surface roughness may provide one or more gas evacuation channels, also when the pushing body 42 supports on the glass sheet surface 2b.

[0639] Figs. 23A-23D illustrates various embodiments of a pushing body 42 according to various embodiments of the present disclosure.

[0640] The pushing body in fig. 23A has a surface 42a configured so that when the support surface 42a of the pushing body support on the glass sheet 2 surface 2b, the surface of the covering body 21 will be substantially flush with the surface 2b of the glass sheet 2.

[0641] The pushing body 42 in fig. 23B comprises a protruding part for engaging with the surface 21b of the covering body 21. This provides that when the surface 42a of the pushing body 42 support on the glass sheet 2 surface 2b, the surface 21b of the covering body 21 will be arranged below the surface 2b of the glass sheet 2.

[0642] The pushing body 42 in fig. 23C comprises a recessed part for engaging with the surface 21b of the covering body 21. This provides that when the surface 42a of the pushing body 42 supports on the glass sheet 2 surface 2b, the surface 21b of the covering body 21 will be arranged above the surface 2b of the glass sheet 2. For example, the pushing body may be configured so that when the surface 42a of the pushing body 42 supports on the glass sheet 2 surface 2b, the surface 21b of the covering body 21 may be arranged between 0.1 and 1 mm, such as between 0.1 and 0.5 mm, for example between 0.2 and 0.4 mm above the surface 2b of the glass sheet 2.

[0643] In embodiments of the present disclosure, the evacuated gas may be evacuated through the pushing body 42.

[0644] In still further embodiments of the present disclosure, as illustrated in fig. 23D, the pushing body 42 may comprise or consist of a material structure which is pervious to the evacuated gas GA. Since the material structure may be pervious to the evacuated gas GA, the evacuated gas may be evacuated through openings such as pores of the pushing body 42 during evacuation, and into the cup interior 9a. Hence, even when the pushing body support on the glass sheet 2a surface, gas may be evacuated through at least a part of the pushing body 42. For example, the pushing body 42 may in some embodiments comprise a sintered part, such as a block, of material, for example sintered metal, sintered ceramics and / or sintered glass in order to obtain a body 42 part pervious to the evacuated gas. In some embodiments, a part of the pushing body 42 proximate the covering body 21 may be pervious to the evacuated gas GA, whereas a part of the pushing body 42 distant to the covering body 21 may be non-pervious to the evacuated gas. In other embodiments, substantially the entire pushing body may comprise or consist of the material structure pervious to the evacuated gas GA.

[0645] In still further embodiments of the present disclosure, the pushing body 42 may comprise one or more through holes (not illustrated), which guides the evacuated gas GA through the pushing body 42.

[0646] As can be seen in fig. 23D, the pushing body 42 may be displaced by the support on the glass sheet 2 surface 2b.

[0647] It is understood that in still further embodiments of the present disclosure, the pushing body 42 may not be pushed to a location where it support on the major glass sheet surface 2b. Instead, the clamping part / pushing part 40 may be configured to provide the desired force, and hence the pushing force F1 from the clamping part / pushing part 40 may determine the amount of displacement of the covering body 21 towards the support surface 10s. This may e.g. be obtained in combination with the properties, such as the softening properties, of the of the seal material 22. The heating temperature of the seal material 22 may be controlled by the heater (see ref. 7 of figs. 22 and 2), e.g. in order to obtain the desired seal material viscosity.

[0648] Figs. 23A-25C illustrates various embodiments of the present disclosure, wherein a plurality of covers 20 ( see Figs. 24C, 25C) are obtained from a cooled covering body workpiece (which has been heated in the working space 50, figs. 24A, 25A). Each cover (20) obtained from said covering body workpiece (21) comprises a part of the workpiece 21 body and the solidified glass solder material. The covers 20 may e.g. be cut (see fig. 24B, 25B), from the workpiece.

[0649] Figs. 24A-24C illustrates schematically an embodiment of the present disclosure, wherein a plurality of covers 20 are manufactured from and obtained from a single covering body workpiece 21. The workpiece 21 comprises a plurality of discretely arranged portions of seal material 22 which are distributed across a surface of the workpiece 21, such as a single glass sheet or metal sheet. The seal material portions may in some embodiments have a substantially identical size and shape, and a plurality of substantially identical covers 20 may be obtained from the same workpiece.

[0650] The seal material portions may e.g. be arranged onto the surface by means of a nozzle, by means of printing, such as 3D printing, may be applied applying by means of smearing and / or the like.

[0651] The covering body workpiece 21 with the seal material portions thereon is arranged in the working space 50.

[0652] The workpiece 21 with the discretely arranged seal material portions 22 disposed thereon is first heated (Fig. 24A) in the working space 50, e.g. as previously described, see e.g. fig. 50 and the description thereto. The seal material 22 is heated in the working space 50 to a target temperature Tar21 by means of a heater 60, e.g. as previously described, see e.g. one or more of figs. 13-16 and the description relating thereto. This may provide an outgassing of the seal material as e.g. previously described.

[0653] When the seal material portions 22 has been heated and outgassed, the heated glass solder material 22 and the covering body workpiece is cooled so as to solidify the glass solder material.

[0654] In fig. 24B, the covering body workpiece with the now fired, solidified seal material thereon is then processed further so as to obtain a plurality of covers from the single workpiece 21 comprising the solidified seal mateiral. In this example, a cutter 110 is used for obtaining the covers 20. The cutter may e.g. comprise or be a laser cutter, a waterjet cutter, a saw, such as a band saw and / or the like.

[0655] The covers 20 obtained from said covering body workpiece 21 each comprises the solidified glass solder material 22. In the illustrated example, the solidified seal material may be attached to the covering body 21 and be configured to encompasses the through hole of the VIG unit assembly in an uninterrupted manner. In fig. 24A, the seal material obtains this by being a continuous ring of seal material.

[0656] Hence, each cover 20 will be cut from the workpiece 21 to comprises one of the discretely arranged solidified portions of the seal material. See fig. 24C.

[0657] Figs. 25A-25C illustrates schematically further embodiments of the present disclosure, wherein a plurality of covers 20 are manufactured from a single covering body workpiece 21. Here, the seal material 22 at the workpiece 21 comprises or consist of a substantially continuous layer of seal material, such as a continuous layer of the glass solder material. This is heated in the working space 50 as e.g. previously disclosed, for example to outgas the seal material 22, and the entire workpiece 21 is then cooled to tool and solidify the seal material 21.

[0658] A plurality of covers 20 are obtained, such as cut by means of a cutter 110, from the workpiece 21 (see fig. 25B) so that a plurality, such as at least 5, at least 20 or at least 50, of the obtained covers 20 (se fig. 25C) comprises a part of the covering body workpiece 21 and a solidified seal material 22 originating from the continuous layer of seal material 22. In this embodiment, the solidified seal 22 material of the provided covers 20 is a continuous layer of seal material which extends over substantially the entire surface that is configured to face the evacuated gap.

[0659] It is understood that in further embodiments of the present disclosure (not illustrated), the workpiece 21 may comprise a plurality of discretely arranged portions of seal material, and a plurality of covers may be provided, such as cut, from an area of the workpiece 21 comprising one of the portions of the seal material.

[0660] It is generally understood that in some embodiments of the present disclosure, the seal material may be applied onto the workpiece to have a predetermined shape, such as e.g. according to a predetermined template. The template may be a physical template or a digital template that is stored on a data storage. A computer processor may be configured to control a printer, such as a 3D printer, control a nozzle and / or the like according to the digital template so as to apply the seal material onto the workpiece 21 in accordance with the template so as to obtain the desired seal material 22 layout on the workpiece 21. It is understood that the workpiece 21 from which the covers are obtained in some embodiments of the present disclosure may be made from e.g. metal or glass, such as annealed glass.

[0661] The seal material 22 at the cover 20 in fig. 25c comprises a substantially continuous layer of solidified glass solder material, since it has been cut out from a covering body comprising continuous solidified seal material (see fig. 25B). In some embodiments, the seal material of the obtained covers may cover at least 50%, such as at least 70%, such as at least 90% of the surface of the covering body. In some embodiments, the seal material of the obtained covers may cover at least 95%, of the surface of the covering body.

[0662] Fig. 26 illustrates schematically an embodiment of the present disclosure wherein a cover comprising a continuous layer of seal material is used for sealing the evacuated gap. As can be seen, the surface roughness of the seal material surface 22a may be sufficient to provide one or more gas passages 25 for the evacuated gas GA. Again, in some embodiments, the glass sheet surface 10s facing the seal material 22 may or may not have a surface roughness that helps to provide or increase the size of, gas passages 25. The surface roughness of the seal material 22 of the cover and / or the surface roughness of the glass sheet surface 10s may e.g. be as described above according to various embodiments of the present disclosure.

[0663] Figs. 27A-27C illustrate schematically heating profiles for manufacturing one or more covering body workpieces 21 each comprising a glass solder material 22 that is solidified, according to various embodiments of the present disclosure. It is generally understood that the temperature illustrated in the figures may be the temperature T21 of the one or more cover body workpieces 21. Alternatively, it may be the temperatures inside the working space 50. Otherwise, it may illustrate the set temperature (as opposed to the actual temperature) inside the working space 50. It is generally understood that the heating profiles of figs. 27A-27C may provide further embodiments of the heating described previously in order to obtain the solidified solder material 22, or may be alternatives thereto. Fig. 27A shows a heating profile, where the temperature is ramped according to predetermined linear heating ramps. A number of Heating steps TStep, Tbb, where the temperature is maintained constant, are interposed between the initial temperature Tinit and the target temperature Tar21. These steps may be provided to enable a switch between, e.g. linear, heating ramp speeds and / or they may help to provide an improved binder burnout Tbb before softening the glass solder material 22 at the target temperature Tar21.

[0664] In certain embodiments, the linear ramping speeds may decrease as the temperature is increased towards the target temperature Tar21. Hence, the gradient of the heating may be configured to reduce as the temperature gets closer to the target temperature. It can for example be seen that the gradient between Tinit and Tstep is larger than the gradient between Tbb and target temperature Tar21. This may e.g. in some embodiments aid in providing a stronger sealing of the evacuated gap at the evacuation hole, as a slow heating may provide a solidified sealing material 22 with a low (or substantially no) amount of binder remaining and / or with a desired, such as high, surface roughness at the solidified solder material that may help to provide or increase the size of gas passages 25.

[0665] After holding the target temperature Tar21 for a certain period (between the end of the heating Tend and the beginning of the cooling Tc), the one or more covering body workpieces 21 are cooled. This may proceed according to the heating profile illustrated in Fig. 27A, where the covering body workpiece(s) 21 are first cooled according to a controlled cooling ramp to a cooling temperature Tcool, where they are kept for a predetermined period of time. This period may be longer, e.g. in order to enable a homogenization of the solidifying glass sealing material 22. After this holding period at the cooling temperature Tcool, the covering body workpieces 21 may be allowed to cool naturally to room temperature, see from time Tn.

[0666] Fig. 27B illustrates a further embodiment of a heating profile, where the covering body workpiece(s) 21 temperature is ramped directly to a binder burnout temperature Tbb without an interposed / intermediate step. It is generally understood that any number of constant temperature steps may be provided during any part of the manufacturing procedure, according to various embodiments of the present disclosure. For example, in some embodiments, between 1 and 10 heating steps, such as between 1 and 5 heating steps may be provided (endpoints included).

[0667] Fig. 27C illustrates a heating profile according to further embodiments of the present disclosure, where the temperature changes between the set temperatures TStep, Tbb, Tar21 , Tcool are substantially instantaneous set rather than a controlled ramp according to e.g. linear heating ramp profiles as in Figs. 27A-B. In this embodiment, the temperature illustrated may be the temperature inside the working space 50 or it may be the set temperature of the working space 50 such that the actual temperature inside the working space 50 and / or the temperature of the one or more cover body workpieces 21 may follow a different, such as a more gradual, temperature profile. A substantial instantaneous temperature change may be provided by means of powerful heaters of any kind, by exchanging the air surrounding the one or more cover body workpieces 21, or by quickly moving the one or more cover body workpieces 21 between different compartments inside the working space 50 which have different temperatures.

[0668] According to alternative embodiments, the heating increase may proceed according to a different profile than the ones illustrated in Figs. 27A-C. For example, the heating rate may increase gradually according to a non-linear heating profile, such as an exponential and / or logarithmic heating profile.

[0669] The binder burnout temperature (Tbb) may be 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.

[0670] The controlled binder burnout temperature (Tbb) holding period may have a duration of at least 15 minutes, such as at least 30 minutes, such as at least 60 minutes. Additionally or alternatively, the controlled 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. Additionally or alternatively, 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. The target temperature (Tar21) may be in the range of 300 - 500 °C, such as in the range of 350 - 450 °C, such as in the range of 370 - 400 °C. Additionally or alternatively, the target temperature (Tar21) may be at least 300 °C, such as at least 350 °C, such as at least 370 °C. Additionally or alternatively, the target temperature (Tar21) may be less than 500 °C, such as less than 450 °C, such as less than 400 °C.

[0671] The cooling temperature (Tcool) may be in the range of 200 - 350 °C, such as in the range of 250 - 325 °C, such as in the range of 280 - 310 °C. Additionally or alternatively, the cooling temperature (Tcool) may be at least 200 °C, such as at least 250 °C, such as at least 280 °C. Additionally or alternatively, the cooling temperature (Tcool) may less than 350 °C, such as less than 325 °C, such as less than 310 °C.

[0672] The controlled, such as constant, cooling temperature (Tcool) holding period may have a duration of at least 2 hours, such as at least 6 hours, such as at least 10 hours. Additionally or alternatively, the controlled, such as constant, cooling temperature (Tcool) holding period may have 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. Additionally or alternatively, the controlled, such as constant cooling temperature (Tcool) holding period has a duration of less than 24 hours, such as less than 18 hours, such as less than 14 hours.

[0673] One example of a heating profile may comprise heating the covering body workpieces 21 from room temperature to a Tstep of 180 °C with a heat increase rate 120 °C / h corresponding to 2 °C / min. After a 5 minute dwell time at 180 °C, the covering body workpieces 21 are heated to a binder burnout temperature Tbb of 260 °C with a heat increase rate of 60 °C / h corresponding to 1 °C / min. Following a binder burnout temperature holding period of 1 hour dwell time at Tbb = 260 °C, the covering body workpieces 21 are further heated to the target temperature Tar21 of 370 °C with a heat increase rate of 30 °C / hour corresponding to 0.5 °C / min. The covering body workpieces 21 are kept at this target temperature Tar21 for a 2 hours dwell time before being cooled to 300 °C with a cooling rate of 60 °C / hour. The cooling temperature holding time is 12 hours dwell time, before the covering body workpieces 21 are allowed to naturally cool to room temperature. For all the heating profiles illustrated in Figs. 27A-C, it is generally understood that all or some of the manufacturing procedure may take place in a reduced atmosphere. For example, the working space 50 may comprise a vacuum chamber. The binder burnout at the binder burnout temperature Tbb may for example proceed under atmospheric pressure, while the subsequent heating to the target temperature Tar21 may take place under vacuum. The holding period at the target temperature Tar21 and subsequent cooling and holding at a cooling temperature Tcool may similarly be performed under a vacuum I reduced pressure, e.g. as previously described. The vacuum may provide an inert atmosphere that may affect the surface chemistry of the glass solder material 22 or one or more cover body workpieces 21. For example, heating to the target temperature Tar21 may serve the additional purpose of cleaning the surface of the one or more cover body workpieces 21 as organic residue may evaporate from the surface. By maintaining a vacuum during the heating and subsequent cooling, the surface can be maintained in a substantially clean state. This may be advantageous for the use of the cover body workpiece 21 for sealing the evacuated gap 6 of a vacuum insulated glass unit 1 , where impurities may deteriorate the desired vacuum level inside the evacuated gap.

[0674] Additionally or alternatively, a reduced atmosphere may influence the outgassing properties of the glass solder material 22. For example, it may cause bubbles of outgassing organic species to form and aggregate at the surface of the glass solder material 22. This may provide a high level of surface roughness when the glass solder material 22 cools and solidifies. Alternatively, a reduced atmosphere may e.g. help to reduce the number and size of bubbles, such as gaseous inclusions, forming at the surface of the glass solder material 22 to provide a more dense solidified glass solder material 22 that may aid in providing a strong and hermetic sealing of the evacuated gap 6 of the vacuum insulated glass unit 1.

[0675] In a further embodiment, the entire manufacturing process illustrated in Figs. 27A-C may proceed under a reduced atmosphere.

[0676] In addition to a reduced atmosphere, or alternatively to a reduced atmosphere, the one or more cover body workpieces 21 may in some embodiments of the present disclosure be subjected to an active gas, such as ozone O3 during the manufacturing process. This flushing of active gas may be provided at any time during the manufacturing process illustrated in Figs. 27A-C. For example, the cover body workpieces 21 may be subjected to cycles of alternating reduced pressure and flushing of an active gas. This may provide a scrubbing or a cleaning of the surface of the heated cover body workpieces 21. Additionally or alternatively, the influx of air may provide a force to burst the bubbles forming in the softened glass solder material 22.

[0677] It is generally understood that in some embodiments of the present disclosure, the obtained covers 20 may substantially after manufacturing thereof be placed and stored in a container (not illustrated). The environment in the container may be controlled, such as a reduced, such as a sealed, atmosphere environment in the container in order to reduce contamination of the cover, such as the covering body and solidified solder material. Here the obtained covers comprising the solidified seal material may be stored substantially until it / they 20 is / are to be used for sealing the gap 6 of a VIG unit 1. In some embodiments, the wherein the controlled atmosphere environment comprises a desiccator. An some embodiments, a getter or the like may be configured to be active during the period where the covers are arranged in the container, the getter may e.g. be placed in the container with the stored covers. In some embodiments, the controlled atmosphere environment may be 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.

[0678] Hence, during manufacturing of the VIG unit 100, an obtained cover 20 may be collected from the container containing the controlled, such as reduced, such as sealed, atmosphere environment, and the collected cover is placed to cover the through hole and so that the solidified solder material is configured to be heated by a heater when the gap of the VIG unit assembly has been evacuated, e.g. as previously described.

[0679] Figs. 28A-31 illustrate schematically various further geometries of a cover body I covering body 21 where protrusions 53 or gaps 54 in the circumference of the cover body 21 side surface 21c are introduced. These protrusions 53 or gaps 54 may help to provide an improved air passage between the side surface 21c of the covering body 21 and a side surface 10bs of the first glass sheet which faces the side surface 21 c of the covering body 21 and provide a centering of the cover body 21 in a stepped through hole 10 as e.g. described above and / or below. The protrusions may help to place the covering body in a desired position in a larger diameter portion of the stepped through hole, which may help to e.g. assure consistent and / or efficient gap evacuation when manufacturing larger quantities of VIG units. The protrusions 53 and / or gaps 54 are understood to extend at least 30%, such as at least 50%, such as all of the height of the cover body 21.

[0680] In the case of the geometry illustrated in Figs. 28A-B, protrusions 53 will cause the majority of the side surface 21c all around the covering body 21 to be displaced by at least the depth of the protrusion 54 from the side surface 10bs of the larger diameter portion 10b of the stepped through hole 10 in the first glass sheet 2. The number of protrusions 54 may be one or more, preferably two or more or three or more, and they 53 may e.g. in further embodiments be spaced at equal angles around the outer boundary OB, such as circumference, of the side surface 21c of the cover body 21.

[0681] In the case of the geometry illustrated in Figs. 29A-B, gaps 54, such as recesses, such as grooves, are provided in the side surface 21c of the cover body 21. These gaps 54 may help to improve efficient air passages or channels between the side surface 21c of the cover body 21 and the side surface 10bs of the first glass sheet 2 facing a larger diameter portion of the evacuation hole during the step of evacuating the gap 6 of the vacuum insulated glass unit 2. The number of gaps 54 may be one or more, such as two or more or three or more (four are illustrated in fig. 29A, three are illustrated in fig,. 29B) and they may or may not, in further embodiments of the present disclosure, be spaced at equal angles around the circumference of the side surface 21c of the cover body 21. In figs. 29A-29B, the gaps 54 are recesses that are spaced at equal angles around the circumference, in Fig. 29A with a mutual angle of 90° between them 54, and in Fig. 29B with a mutual angle of 120° between them 54.

[0682] Fig. 30 illustrates a cover body 21 geometry where both protrusions 53 and gaps 54 are provided at the circumference of the side surface 21c. It is understood that more than two protrusions may be provided, e.g. as illustrated in figs 28A-28B.

[0683] Similarly, Fig. 31 illustrates an example of a cover body 21 geometry, where the “protrusions” 53 and “gaps” 54 are formed by vertices 53 and edges 54 of a polygon. In the case of Fig. 31, a heptagon is illustrated, but any shape (regular or irregular), such as a polygonal shape, such as a e.g. a pentagon, hexagon, heptagon, octagon or more may be used. If the through-hole 10 is circular, the shape illustrated in Fig. 31 may provide a cover body 21 that is self-centered in the through-hole 10 by means of the vertices 53 of the polygon while allowing air to more efficiently flow between the side surface 10bs of the first glass sheet 2 and the cover body 21 at the positions of the edges 54 of the polygon, where the distance between the cover body 21 and the side surface 10bs of the first glass sheet 2 is larger than at the vertices 53.

[0684] The gaps 54 and / or protrusions 53 may be of a semicircular shape, see e.g. figs 28A- 30. The radius of the semicircular cross section may be in the range of 1 - 20%, such as 2 - 15%, such as 5 - 10% of a width of the covering body (21) surface (21a) comprising the solder material (22). Additionally or alternatively, the radius of the semicircular cross section may be 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.

[0685] Alternatively, the gaps 54 and / or protrusions 53 may be of a different shape but still have a similar or identical dimension as described above. This is for example the case for the polygonal “protrusions” and “gaps” illustrated in Fig. 31.

[0686] Following the step of heating and cooling the cover body workpieces so as to obtain a dense solidified glass solder, the surface 22a of this glass solder 22 may have a certain surface roughness. In some embodiments of the present disclosure, the surface of the solidified solder material may be postprocessed in order to achieve a more preferred surface roughness and / or shape and / or glass solder topology or glass solder material 22 layout of the solidified solder material 22 of the cover 20 than the one obtained after the heating step provided so as to obtain the solidified solder material. Such postprocessing can for example comprise shaping the solidified seal material 22 by means of one or more shaping tools 58. This could for example entail laser treatment, either surface modification or laser drilling. Additionally or alternatively, it may comprise milling, such as by means of a saw or drill, an abrasive and / or the like. Additionally or alternatively, shaping of the solidified seal 22 may comprise etching, such as chemical or physical etching.

[0687] Fig. 32 illustrates schematically a cross section through a cover 20 according to embodiments of the present disclosure. A glass solder material 22 has been applied to a major surface 21a of the cover body 21 and has been heat-treated as e.g. described previously to outgas the solder material, soften the solder material and / or the like. The figure shows an example of post-shaping of the solidified seal 22, where predefined evacuation channels 53 are cut into the surface 22a of the solder material 22 by means of a shaping tool 58. The figure shows a laser cutter 58 for shaping the solidified solder material 22 by means of a laser beam 58a, although the channels 53 may be obtained by means of milling, sawing, drilling, etching, etc. e.g. as described previously.

[0688] As illustrated in the figure, the predefined channels 53 need not extend all the way through the height of the solidified seal 22. Rather, a remaining part of the seal 22 may be left as a “floor” to the predefined channel 23 (or a ceiling when the cover 20 is placed on the solidified seal 22 part on the first glass sheet 2. This may e.g. help to improve the bonding of the solder material to the glass sheet 2 and close the gap 23 when the cover is used for sealing an evacuated gap.

[0689] The predefined evacuation channel(s) 53 of the cover 20 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) 53 of the cover 20 may be deeper and / or wider than paths in the surface of the solidified solder material 22 caused by surface roughness. The predefined evacuation channel(s) 53 of the cover 20 may be shaped to extend along a predefined evacuation path Devac at a predetermined location.

[0690] Fig. 33 shows a top view of a cover 20, viewed towards the solidified solder material 22, where six predefined channels 23 have been shaped in the solidified seal 22. The glass solder 22 has been omitted and / or removed in a central area 26. This may provide a solution where the risk of softened glass solder running / dripping into the evacuation through hole 10 during the step of sealing the evacuation is reduced. The cut-out in fig. 32 shows a detailed view of one of these channels 23 extending from an inner boundary 26a of the solidified seal 22 to an outer boundary 27b of the solidified seal 22. The direction of evacuation Devac is illustrated as being (in this case) radially outwards from the center area 26 towards the side surface 21c of the cover body 21.

[0691] It is understood that the predefined evacuation channels 23 may be provided in addition to existing gas passages 25 in the surface 22a of the solidified seal 22. Alternatively, existing gas passages 25 in the surface 22a of the solidified seal 22 due to surface roughness may be reduced or even substantially omitted.

[0692] In one or more embodiments, the predefined evacuation channels 23 are cut so as to be linear and radially dissecting the solidified seal material. However, other shapes such as spiral shaped evacuation channels, or another, e.g. predefined pattern of evacuation channels may be provided.

[0693] Generally, the step of shaping the solidified seal 22 may be provided in addition to or as an alternative to using a mold to apply the glass solder frit material 22 in a certain shape with evacuation passages, e.g. before the heat treatment as e.g. previously described to obtain the solidified solder material. For example, a rough outline of a desired seal shape may be provided by a mold during the step of applying the glass frit paste. This shape may be modified during the heating to soften and subsequent cooling of the glass frit paste to obtain the solidified seal 22. For example, surface tension in softened glass frit material 22 may alter the shape of the seal 22 on the cover body surface 21a. Therefore, it may be an advantage to shape the seal 22 afterwards in order to improve the shape and / or reshape the solidified seal material 22 to the desired shape.

[0694] In some embodiments, the seal 22 may be applied in a shape that has no predefined channels or gas passages (apart from those provided by the surface roughness). The step of shaping the solidified seal 22 may thus in some embodiments provide predefined channels 23 and / or improve such as reshape or increase surface roughness.

[0695] In certain embodiments, the initiation of the shaping of the solidified seal 22 may be determined by means of a quality assurance setup, such as a visual inspection and / or automated quality assurance system (not illustrated). Such a quality assurance step may for example comprise a camera. The analysis may for example be provided by a computer algorithm, such as a pre-trained machine learning algorithm and / or deterministic thresholds. The quality assurance system may or may not provide output that is used by the cutting tool to shape the surface of the solidified solder material. Each covering body workpiece 21 with solidified seal 22 may undergo a check to determine whether the shape of the solidified seal 22 is acceptable given a set of predetermined standards, or the check may be done to samples produced.

[0696] A factor for determining and shaping the solidified seal material 22 may be the desired total volume of the gas evacuation channels 23 and / or a total minimum surface area of the gas evacuation channels 23. Additionally or alternatively, the quality assurance system may determine if the surface roughness is adequate and / or if the height of the solidified seal 22 is appropriate at all points or predefined points. If a covering body workpiece 21 does not satisfy the standards, it may be sorted for postprocessing so as to shape the solidified seal 22, and / or the data obtained may be used for shaping the solidified solder material.

[0697] Alternatively, all covering body workpieces 21 may undergo subsequent shaping of the solidified seal 22 independently of their particular shape after cooling.

[0698] In some embodiments, the step of shaping the solidified seal 22 may take place before, during or after a plurality of covers 20 are cut from a covering body workpiece 21 , if covers are cut from a covering body workpiece after the solidified seal material has been obtained.

[0699] Fig. 34A-35B illustrates various embodiments of a predefined evacuation channel 23 in a solidified seal 22 when the covering body 21 is placed on the first glass sheet 2. The predefined channel(s) 23 may be obtained by means of shaping predefined channel or channels 23 in the solder material prior to heating and softening it to obtain the solidified seal material, and / or it may be a result of shaping the solidified seal material by means of a cutting tool as e.g. previously described. The cross-section illustrated in Fig. 34A shows a channel that extends from the height He of the solidified solder 22 all the way to the major surface of the covering body 21a. This may provide a large channel that may enable a fast and efficient evacuation of the gap 6 in the VIG unit 1.

[0700] Fig. 34B shows an embodiment of the present disclosure, where the predefined channel 23 only extends partway from the top of the solidified seal 22 so that there is a continuous stretch of solidified seal 22 between the predefined channel 23 and the covering body 21 . This may provide a solidified seal 22 that may be more likely to flow into the channels 23 when the gap 6 has been evacuated. This may be due to the fact that the continuous stretch of solidified seal 22 may be heated to a higher extent than the covering body 21 during the step of sealing the evacuation hole 10. Additionally or alternatively, the surface tension of the softened seal material may cause the continuous stretch of seal material 22 to be a better base for the remaining seal material 22 to flow onto. Additionally or alternatively, the continuous stretch of solidified seal 22 may have provided a good bonding or wetting with the covering body surface, and the re-heated solder material 22 that is to flow into the channel when sealing the VIG unit gap 6 may more easily blend / in with bond with the continuous stretch of solidified seal 22. It is understood that in some embodiments, the height of the continuous stretch of solidified seal 22 between the channel walls may be larger than, lower than or substantially correspond to, the final height of the solder material after the sealing of the evacuated gap.

[0701] It is generally understood that the seal material 22 used for obtaining the solidified solder material may comprise glass solder frit material such as a low melting point glass solder frit material. In some embodiments of the present disclosure, the low melting point glass solder frit material may have a rated glass transition temperature Tg below 360 °C, such as below 330 °C, such as below 315 °C. An example of a solder material 7a glass transition temperature may be between 290 °C and 320 °C, such as between 300 °C and 310 °C.

[0702] In some embodiments of the present disclosure, the low melting point glass solder frit material may have a rated glass transition temperature Tg above 200 °C, such as above 250 °C, such as above 310°C. An example of a solder material glass transition temperature may be between 250 °C and 360 °C, such as between 300 °C and 330°C. Another example of a solder material glass transition temperature may be between 290 °C and 320 °C, such as between 300 °C and 310 °C.

[0703] Another example of a solidified solder material 22 glass transition temperature may be between 310 °C and 360 °C, such as between 320°C and 350 °C, such as between 330°C and 340 °C, endpoints may or may not be included. Another example of a solder material 22 glass transition temperature may be between 330°C and 359 °C, such as between 320°C and 355 °C. In some embodiments of the present disclosure, the solidified low melting point glass solder frit material 22 at the cover 20 may have a rated glass transition temperature Tg above 350 °C, such as above 400 °C, such as above 420 °C.

[0704] In some embodiments of the present disclosure, the low melting point glass solder frit material 22 may have a rated glass transition temperature Tg above 330 °C, such as above 340 °C, such as above 350 °C.

[0705] In some embodiments of the present disclosure, the seal material of the cover may additionally comprise one or more primer layers 28 positioned between the solder material 22 and the covering body 21 and / or between the solder material 22 and the first glass sheet 2. See e.g. the description relating to one or more figures described below, such as e.g. Figs. 35A-36 and Fig. 39. In that case, the solidified seal material 22 may bond to the major surface 21a of the primer layer 28 surface. The / these primer layer(s) 28 may e.g. act as absorbers during the local heating (See e.g. fig. 22 and the description thereto) of the solder material 22. Additionally or alternatively, the primer layer(s) 28 may provide a better match between properties, such as glass transition temperature and / or thermal expansion coefficient of the covering body 21 and the solder material 22. Additionally or alternatively, the primer layer(s) 28 may allow the construction of a more inexpensive VIG unit 1 as glass frit used for primer may be less expensive than the solder material 22. 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.

[0706] It is understood that in other embodiments, the seal at the cover 20 may not comprise (a) primer(s) 28. As described in more details further below, the first glass sheet may additionally or alternatively comprise a primer layer 28 at the first glass sheet so that this primer is placed between the first glass sheet and the solidified seal material 22 of the cover, so as to bond with the solidified seal material 22 of the cover when this is heated and softened so as to seal the evacuated gap. The primer layer 28 at the cover 20 may be arranged on the major surface of the covering body 21 so as to cover at least the same area as the solder material 22 covers. For example, this may result in a cover 20 where the primer layer 28 is or is not visible when the cover 20 is viewed from the side of the solder material 22.

[0707] Alternatively, the primer layer 28 may be arranged so as to cover a larger area than the solder material 22.

[0708] In some embodiments, the primer layer 28 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 some embodiments, the primer layer 28 has a height of at least 10 pm, such as at least 20 pm, such as at least 30 pm. In some embodiments, the primer layer 28 has a height of no more than 100 pm, such as no more than 80 pm, such as no more than 50 pm.

[0709] For example, the primer layer 28 may in some embodiments be arranged across substantially the entire major surface 21a of the covering body 21. 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 26 of the covering body 21 surface 21a may be designed so as to be free from primer layer 28 as well as solder material 22. This may e.g. help to provide an improved barrier that may reduce the risk of the softened solder material 22 flowing into the through hole 10 during the sealing of the through hole 10.

[0710] The primer layer 28 at the cover may in some embodiments cover the major part of the surface 21a of the covering body 21 except the center area 26, for example providing a continuous stretch, such as ring, of material across any predefined evacuation channels 23 provided in the seal material 22. This is illustrated in Fig. 35B. An alternative, where the predefined channel 23 is provided through the primer layer 28 as well as the entire height of the solder material 22 is illustrated in Fig. 35A.

[0711] The primer layer 28 may be efficiently heated during the step of softening, such as locally heating, the solder material 22 so as to seal the through hole 10 after evacuating the gap 6. The heater may also heat the primer layer material at the channel 23. Having a primer layer 28 across the channels 23 may help to provide a heated and thus more susceptible base for the softened solder material 22 to flow across when sealing the evacuated gap and thus removing the channel(s) 23 after the channel(s). This may provide an improved design where the predefined channels 23 are more easily closed during the softening and heating step.

[0712] A top view of a cover 20 comprising a primer layer where 28 the primer layer is removed at the center area 26 of the major cover surface and where the primer extends across predefined channels 23 (in this case two channels) is schematically shown in Fig. 36.

[0713] Additionally or alternatively, a primer layer 28, such as a single layer or multilayer primer layer may be provided on the first glass sheet 2 around the through hole 10. This is schematically illustrated in fig. 37. In the case where the through hole 10 comprises a larger diameter portion 10b and a smaller diameter portion 10a constituting a recessed part, the primer layer 28 may be arranged at the floor surface 10s of the larger diameter portion 10b around the smaller diameter portion 10a. The VIG unit assembly 1 may comprise such a primer layer 28 for the surface 22a solidified seal material 22 of the cover 20 to support on already when the cover 20 is arranged at the first glass sheet, such as in the recessed portion (if present).

[0714] Fig. 38A illustrates schematically an embodiment of the present disclosure wherein the primer layer 28 at the VIG unit assembly comprises a full, substantially un-interrupted ring of primer around the through hole 10, 10a. Alternatively, the primer layer 28 may be a discontinuous shape, such as a ring with one or more openings. This may for example help to provide a more efficient gap evacuation through those openings. This is shown in Fig. 38B.

[0715] Alternatively, if the through hole 10 does not comprise a recessed portion, the primer layer 28 may be placed on the major surface 10s of the first glass sheet 2. This is shown schematically in Fig. 38C in the case of a continuous ring of primer 28 and in Fig. 38D in the case of a discontinuous ring of primer 28. It is understood that the surface of the solidified seal material 22 of the cover may be arranged to support on the primer layer at the VIG unit assembly 1.

[0716] In one or more embodiments, where the first glass sheet 2 is thermally tempered, the primer layer 28 on the first glass sheet 2 may be applied prior to thermally tempering the first glass sheet 2. In this way, the thermal tempering process may serve to e.g. at heat tret, such as at least sinter the primer layer material, such as a glass solder material, so as to obtain the primer layer 28. In one or more embodiments, the primer layer 28 is applied prior to providing the through hole 10. Alternatively, the primer layer 28 may be applied after providing the through hole 10.

[0717] The primer layer 28 on the first glass sheet 2 may help to improve the seal quality, such as particularly the adherence strength of the cover 20 to the first glass sheet 2. For example, the primer layer 28 may be heated during the sealing process to seal the evacuated gap so as to provide a good base for the solder material 22 to flow across and adhere to once it solidifies.

[0718] Fig. 39 illustrates schematically a cross section of a VIG unit 100 according to embodiments of the present disclosure. The VIG unit 100 is laminated and thus comprises a lamination glass sheet 8 that is attached to the first glass sheet 2 by means of a lamination interlayer 8a. The evacuated gap 6 is sealed by means of the cover 20. In fig. 39, a first primer layer 28 is placed between the covering body 21 and the seal material 2, which seal material 22 has a lower softening temperature than the primer 28. Moreover, in fig. 39 a second primer layer 28 is placed between the glass sheet surface 10s and the seal material 22 that has a lower softening temperature than that primer 28. Hence, the seal material 22 (originating from the solidified seal material previously described) has a lower softening temperature than the softening temperature of one or both primers.

[0719] It is however understood that in some embodiments, one or both primer layers 28 illustrated in fig. 39 may be omitted.

[0720] In one or more embodiments of the present disclosure, the solder material 22 comprises one or more inorganic oxides, such as at least 50% by weight of one or more inorganic oxides.

[0721] In one or more embodiments of the present disclosure, the 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. In one or more embodiments of the present disclosure, the solidified solder 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, TeCU, TeCh, and / or TesC

[0722] In one or more embodiments of the present disclosure, the Te / V-based solder material additionally comprises one or more of AI2O3, SiC>2, MgO, P2O5, Bi20s, 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.

[0723] In one or more embodiments of the present disclosure, the solder material 22 comprises Bi20s in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0724] In one or more embodiments of the present disclosure, the solder material 22 comprises B2O3 in combination with one or more of the following metal oxides: SiO2, 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.

[0725] In one or more embodiments of the present disclosure, the solder material 22 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.

[0726] In one or more embodiments of the present disclosure, the solder material 22 comprises less than 1 wt-%, such as less than 0.5 wt-%, such as less than 0.1 wt-% of Pb and V.

[0727] In one or more embodiments of the present disclosure, the solder material 22 has a glass transition temperature Tg, such as a rated glass transition temperature, higher than 300 °C, such as higher than 320 °C.

[0728] In one or more embodiments of the present disclosure, the solder material 22 has a glass transition temperature Tg, such as a rated glass transition temperature, higher than 340 °C, such as higher than 350 °C. In one or more embodiments of the present disclosure, the solder material 22 has a glass transition temperature Tg lower than 400 °C, such as lower than 390 °C, such as lower than 380 °C.

[0729] In one or more embodiments of the present disclosure, the solder material 22 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.

[0730] In one or more embodiments of the present disclosure, the solder material 22 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.

[0731] In one or more embodiments of the present disclosure, the solder material 22 has a melting temperature Tm higher than 400 °C, such as higher than 420 °C, such as higher than 450 °C.

[0732] 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.

[0733] In one or more embodiments of the present disclosure, the solder material 22 comprises a solder base material, such as a solder base material according to the previously disclosed aspects 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.

[0734] 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.

[0735] In one or more embodiments of the present disclosure, one or both of the the one or two primer layers 28 comprises 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 28 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.

[0736] In one or more embodiments of the present disclosure, each of the one or two primers 28, 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.

[0737] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 comprise Bi20a in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0738] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 comprise Bi, such as Bi20s in combination with Na2O and SiC>2.

[0739] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 (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-%.

[0740] In one or more embodiments of the present disclosure, the one or two primer layers 28 comprise less than 1 wt-%, such as less than 0.5 wt-%, such as less than 0.1 wt-%, of Pb and V.

[0741] In one or more embodiments of the present disclosure, the one or two primer layers 28 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.

[0742] 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.

[0743] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 has a glass transition temperature higher than 300 °C, such as higher than 320 °C, such as higher than 350 °C.

[0744] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 has a glass transition temperature higher than 400 °C, such as higher than 430 °C, such as higher than 480 °C.

[0745] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 have a glass transition temperature lower than 480 °C, such as lower than 450 °C.

[0746] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 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.

[0747] In one or more embodiments of the present disclosure, one or both of the one or two primer layers 28 may have a melting temperature (Tm) higher than 450 °C, such as higher than 480 °C, such as higher than 500 °C.

[0748] It is generally understood that the primer(s) 28 of the seal remains harder than the solder material 22, such as substantially un-softened, during substantially the entire heating of the solder material 22 by means of the one or more heating beams such as laser light beams.

[0749] It is generally understood that in some embodiments of the present disclosure, the step of heating and softening the solder material 22 by means of the one or more heating beams may be preceded by a step of affixing the one or more primer layers 28 onto a glass sheet 21 covering body 21, such as during thermal tempering of said glass sheet 2. In order to obtain a strong through hole 10 sealing, the primer layers 28 may be bonded to the glass sheet 2 at a temperature higher than that necessary to soften the solder material 22 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.

[0750] It is generally understood that the solder material types mentioned above may be used for the seal material 22, 28 of the cover and / or for the edge seal material 4 (see e.g. fig. 1) that encloses the evacuated gap.

[0751] It is generally understood that the solder material used at the edge seal 4 (see e.g. fig. 1) may or may not comprise one or more single layer or multi-layer primer layers (not illustrated). An a first edge seal material of the edge seal 4 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

[0752] • 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

[0753] • comprise Bi2Os,e g. in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

[0754] The primer layer(s) of the edge seal 4 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 edge seal 4 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 4 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 4, 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.

[0755] It is understood that the temperatures such as glass transition temperature, Littleton temperature and / or the like mentioned above may also or may not apply for the edge seal material, such as the above mentioned edge seal material, of the edge seal.

[0756] It is however understood that in other embodiments, the edge seal 4 may comprise edge seal solder material without the use of one or more primers.

[0757] In one or more embodiments of the present disclosure, the step of heating the solidified seal material comprises raster scanning a laser beam across the surface of the solidified solder material that faces away from the covering body. Fig. 40 shows a laser raster pattern that can be used in the step of heating the solidified seal material 22 so as to close the gap 6 of the VIG unit 1 , see e.g. also fig. 22. The pattern comprises narrowly spaced parallel straight lines.

[0758] In one or more embodiments of the present disclosure, the 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.

[0759] 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.

[0760] 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.

[0761] 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 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.

[0762] In one or more embodiments of the present disclosure, the 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.

[0763] 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.

[0764] Items

[0765] Various embodiments of the present disclosure is moreover described in the below items:

[0766] 1. 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), wherein said method comprises:

[0767] - providing one or more covering body workpieces (21), wherein said one or more covering body workpieces (21) comprises a seal material (22), such as comprising 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),

[0768] - arranging the one or more covering body workpieces (21) in a working space (50),

[0769] - 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,

[0770] - cooling the one or more heated covering body workpieces (21) and seal material (22) so as to solidify the seal material (22),

[0771] - obtaining one or more covers (20) from the one or more cooled covering body workpieces (21).

[0772] 2. Method according to item 1 , wherein said heating of the seal material (22) comprises heating to a temperature above 200°C, such as above 300°C, such as above 350°C. 3. Method according to item 1 or 2, 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.

[0773] 4. Method according to any of the preceding items, wherein said working space (50) 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.

[0774] 5. Method according to item 4, wherein said reducing of the pressure in the vacuum chamber (50) comprises reducing the pressure in the vacuum chamber to a pressure below 500 mbar, such as below 100 mbar, such as below 10 mbar.

[0775] 6. Method according to item 4 or 5, wherein said reducing of the pressure in the vacuum chamber (50) comprises reducing the pressure in the vacuum chamber (50) to a pressure below 500 millibar such as below 100 millibar.

[0776] 7. Method according to item 4, 5 or 6, wherein the method comprises equalizing said pressure in the vacuum chamber (50), such as during or after said cooling in the vacuum chamber (50).

[0777] 8. Method according to any of the preceding items, wherein said heating (60) comprises heating the glass solder material (22) to a temperature above the rated glass transition temperature (Tg) of the glass solder material (22).

[0778] 9. Method according to any of the preceding ite...

Claims

1. Claims1. 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), wherein said method comprises:• providing one or more covering body workpieces (21), wherein said one or more covering body workpieces (21) comprises a seal material (22), such as comprising 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),• 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).

2. The method according to claim 1, wherein said heating of the seal material (22) comprises heating to a temperature above 200°C, such as above 300°C, such as above 350°C.

3. The method according to claim 1 or 2, 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.

4. The method according to any of the preceding claims, wherein said working space (50) 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.

5. The method according to claim 4, wherein said reducing of the pressure in the vacuum chamber (50) comprises reducing the pressure in the vacuum chamber to a pressure below 500 mbar, such as below 100 mbar, such as below 10 mbar.

6. The method according to claim 4 or 5, wherein said reducing of the pressure in the vacuum chamber (50) comprises reducing the pressure in the vacuum chamber (50) to a pressure below 500 millibar such as below 100 millibar.

7. The method according to claim 4, 5 or 6, wherein the method comprises equalizing said pressure in the vacuum chamber (50), such as during or after said cooling in the vacuum chamber (50).

8. The method according to any of the preceding claims, wherein said heating (60) comprises heating the glass solder material (22) to a temperature above the rated glass transition temperature (Tg) of the glass solder material (22).

9. The method according to any of the preceding claims, wherein the temperature (T21) of the seal material (21) is increased in the working chamber (50) 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 (Ht21 ), such as until the target temperature (Tar21) is reached.

10. The method according to any of the preceding claims, wherein the temperature (T21) of the seal material (21) is increased in the working chamber (50) 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 (Tar21) is reached.

11. The method according to claim 9 or 10, wherein 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 (Ht21).

12. The method according to any of the preceding claims, wherein the heating time (Ht21) before the seal material (22) reaches the target temperature (Tar21) is at least 3 hours, such as at least 5 hours, such as at least 8 hours.16913. The method according to any of the preceding claims, 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).

14. The method according to claim 13, wherein the temperature (T21) of the seal material (22) is increased stepwise in the working chamber (50) according to two or more heat increase rates between the time of initiating the heating (Tinit) and time (Tend) of reaching the target temperature (Tar21).

15. The method according to any of claims 13-14, wherein the heat increase rate, such as heating gradient, is decreased as the temperature (T21) of the seal material (22) is increased.

16. The method according to claim 15, wherein the heat increase rate is controlled so as to decrease gradually as the temperature (T21) of the seal material (22) is increased.

17. The method according to claim 15, wherein the heat increase rate decreases in a stepwise manner as the temperature (T21) of the seal material (22) is increased, such as wherein the heat increase rate decreases after one or more temperature holding periods such as controlled temperature holding periods.

18. The method according to any of claims 1-17, wherein said heating of the seal material (22) comprises heating at a controlled 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.

19. The method according to claim 18, wherein the controlled 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 / or170 wherein the controlled 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.

20. The method according to any of claims 18-19, wherein the one or more covering body workpieces (21) are in a reduced atmosphere during the binder burnout temperature (Tbb) holding period.

21. The method according to any of claims 18-20, wherein the one or more covering body workpieces (21) are at atmospheric pressure during the binder burnout temperature (Tbb) holding period.

22. The method according to any of the preceding claims, wherein said cooling of the one or more heated covering body workpieces (21) and seal material (22) comprises a controlled, such as constant, cooling temperature (Tcool) holding period.

23. The method according to claim 22, wherein the controlled, such as constant, cooling temperature (Tcool) holding period has a duration of at least 2 hours, such as at least 6 hours, such as at least 10 hours, and / or wherein the controlled, such as constant, cooling temperature (Tcool) 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, and / or wherein the controlled, such as constant cooling temperature (Tcool) holding period has a duration of less than 24 hours, such as less than 18 hours, such as less than 14 hours.

24. The method according to any of claims 22-23, wherein the one or more covering body workpieces (21) are in a reduced atmospheric pressure during the controlled, such as constant, cooling temperature (Tcool) holding period.17125. The method according to any of claims 22-23, wherein the one or more covering body workpieces (21) are at atmospheric pressure during the controlled, such as constant, cooling temperature (Tcool) holding period.

26. The method according to any of the preceding claims, wherein said heating of the seal material (22) during the heating time (Ht21 ), such as until the target temperature (Tar21) is reached, comprises subjecting the one or more covering body workpieces (21) to an active gas, such as a noble gas, such as ozone.

27. The method according to any of the preceding claims, wherein said heating of the seal material (22) at the target temperature (Tar21), comprises subjecting the one or more covering body workpieces (21) to an active gas, such as ozone.

28. The method according to any of the preceding claims, wherein the heater (60) comprises a radiation heater, such as a laser.

29. The method according to any of the preceding claims, wherein the heater (60) heats a conduction heating part (95), such as a base, configured to heat the one or more covering body workpieces (21), so that the one or more covering body workpieces (21), heats the seal material (21).

30. The method 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%.

31. The method 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%.

32. The method according to any of the preceding claims, wherein said heating by means of said heater (60) reduces the amount of binder material in the seal material (22), 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 (60), and / or172 wherein, 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 above 0.1 wt%, such as above 0.4 wt%, such as above 1 wt%, and / or wherein 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 between 0.1 wt% and 5 wt%, such as between 0.4 wt% and 2 wt%.

33. The method according to any of the preceding claims, wherein said heating by means of said heater (60) reduces the amount of solvent material in the seal material (22) 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 (60).

34. The method according to any of the preceding claims, wherein a surface roughness of the surface (22a) of the solidified seal material (22) which faces away from the surface (21a) of the work piece (21) 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.

35. The method according to any of the preceding claims, wherein the surface roughness of the surface (22a) of the solidified seal material (22) which faces away from the surface (21a) of the work piece (21) is between 10 pm, and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 75 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

36. The method according to any of the preceding claims wherein said providing of the one or more covering body workpieces (21) comprises applying the glass solder material (22) to a surface (21a) of the one or more covering body workpieces (21).

37. The method according to any of the preceding claims, such as wherein a softening temperature of the one or more covering body workpieces (21), (21) is higher than a softening temperature of the seal material (22).

38. The method according to any of the preceding claims, such as wherein a softening temperature of the one or more covering body workpieces (21) is higher than a softening temperature of the glass solder material (22).

39. The method according to any of the preceding claims, wherein a surface roughness of the surface (22a) of the solidified seal material (22) which faces away from the surface (21a) of the work piece (21) 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 method according to any of the preceding claims, wherein the surface roughness of the surface (22a) of the solidified seal material (22) which faces away from the surface (21a) of the work piece (21) is between 10 pm , and 150 pm such as between 25 pm and 100 pm, such as between 35 pm and 80 pm, such as wherein said surface roughness is the Ra or Rz surface roughness parameter, preferably the Ra parameter.

41. The method according to any of the preceding claims, such as according to claim 24 or 25, wherein said surface roughness of the surface (22a) of the solidified seal material (22) is obtained as a result of said heating (60) of the seal material (22) of the cover (20) by means of the heater (60) and the subsequent cooling of the softened seal material (22) so as to solidify the seal material.

42. The method according to any of the preceding claims, such as according to claim 24, 25, or 26, wherein said surface roughness of the seal material (22) surface (22a) 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).

43. The method according to any of the preceding claims, wherein said solidified seal material (22) has a height (H22), 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.

44. The method according to any of the preceding claims, wherein the height (H22), such as local maximum height, of the solidified seal material (22) varies less than 0.1 mm, such as less than 0.05 mm, for example less than 0.03 mm over the entire extent (22e) of the seal material (22).

45. The method according to any of the preceding claims, wherein the surface roughness of the 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, such as substantially randomly, across the surface of the glass solder material (22).

46. The method according to any of the preceding claims, wherein the solidified seal material (22) comprises or consist of a ring of seal material (2), such as a continuous, annular ring of seal material.

47. The method according to any of the preceding claims, such as according to claim 46, wherein the solidified seal material (22) is in continuous, un-interrupted contact with, and continuously adheres to, the covering body (21) surface (21a) over substantially the full extent (22e), such as the full length, of the ring of seal material (2).

48. The method according to any of the preceding claims, wherein said heating of the seal material (22) comprises controlling the gradient of the heating of the solder material (22) so that the gradient is controlled to decrease (Fig. 27A) between the initiation of the heating (Tinit) and the time (Tend) when the target temperature (Tar21) is reached.

49. The method according to claim 48, wherein the gradient of the heating of the solder is controlled to decrease (Fig. 27A) after a binder burnout temperature (Tbb) has been reached.

50. The method according to any of the preceding claims, wherein the seal material comprises a primer layer (28) between the solder material and the covering body, such as wherein the method comprises the step of providing a primer layer (28) on the one or more covering body workpieces (21).17551. The method according to claim 50, wherein the primer layer (28) covers at least the same part(s) of the major surface (21a) of the covering body workpiece (21) as the solder material (22).

52. The method according to any of the preceding claims, wherein the step of obtaining one or more covers (20) comprises providing one or more, such as two or more, such as three or more, protrusions (53) and / or one or more, such as two or more, such as three or more, gaps, such as recesses, (54) in a side surface (21c) of the covering body (21).

53. The method according to any claim 52, wherein the protrusions (53) and / or gaps (54) in the side surface (21c) of the covering body (21) are located equidistantly from each other around the perimeter of the covering body (21).

54. The method according to claim 53, wherein the covering body (21) of each cover (20) has a polygonal cross section, such that each protrusion (53) is provided by a vertex of said polygon and each gap (54) is provided by an edge of said polygon.

55. The method according to any of claims 52-54, wherein each protrusion (53) and / or each gap (54) in the side surface (21c) of the covering body (21) has a semicircular cross section.

56. The method according to claim 55, wherein 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 (21) surface (21a) comprising the solder material (22), and / or wherein 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.

57. The method according to any of the preceding claims, wherein said obtaining of the one or more covers comprises shaping the solidified seal (22) by means of a shaping tool (58).

58. The method according to claim 57, wherein said shaping of the solidified seal (22) by means of the shaping tool (58) comprises shaping, such as re-shaping, at least176 a part of the surface (22a) of the solidified solder material that faces away from the covering body workpiece or covering body.

59. The method according to any of claims 57-58, wherein said shaping of the solidified seal (22) by means of the shaping tool (58) is provided before or after the one or more covers (20) is / are obtained, such as cut from, the one or more cooled covering body workpieces (21).

60. The method according to any of claims 57-59, wherein said shaping of the solidified seal (22) by means of the shaping tool (58) comprises cutting, such as laser cutting, mechanically cutting or etching into the solidified seal material.

61. The method according to any of claims 57-60, wherein said shaping of the solidified seal (22) by means of the shaping tool (58) comprises shaping, such as cutting, one or evacuation channels (23) into the surface (22a) of the solidified seal (22).

62. The method according to claim 61, wherein the one or more shaped evacuation channel(s) (23) is shaped by the shaping tool (58) so as to extend along a predefined paths, such as linear path, such as between an inner side boundary (26a, 26b) of the solidified solder material (22) and an outer side boundary (27a, 27b) of the solidified seal material (22).

63. Method according to any of claims 61-62, wherein one or more of said one or more evacuation channels (23) constitutes a discontinuation.

64. The method according to any of claims 57-63, wherein said shaping of the solidified seal (22) comprises modifying the surface roughness, such as by means of polishing.

65. The method according to any of claims 57-64, wherein said shaping of the solidified seal (22) comprises increasing the surface roughness of the solidified seal material so as to provide a surface roughness in order to reduce the flow resistance when the solidified seal material (22) supports on a glass sheet surface (10s) during evacuation of a gap (6) of a VIG unit assembly (1).17766. The method according to any of claims 57-65, wherein said shaping of the solidified seal (22) comprises shaping (23, 25) the solidified seal material so as to reduce the flow resistance when the solidified seal material (22) supports on a glass sheet surface (10s) during evacuation of a gap (6) of a VIG unit assembly (1).

67. The method according to any of claims 57-66, wherein said shaping of the solidified seal (22) is initiated based on a quality assurance inspection, such as an automated quality assurance inspection.

68. The method according to claim 67, wherein said quality assurance inspection comprises the use of a camera.

69. The method according to any of claims 66-68, wherein said quality assurance inspection comprises comparing, such as correlating, each cover (20), such as a measured or calculated seal material topology representation, with a predefined standard, such as a representation of a predefined, desired surface topology.

70. The method according to claim 69, wherein the step of comparing each cover (20) to a set of predefined standards comprises the use of artificial intelligence, such as machine learning and / or computer vision.

71. The method according to any of the preceding claims, 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 evacuated gap (6) of a vacuum insulating glass (VIG) unit (1).

72. The method according to claim 71 , wherein the controlled atmosphere environment comprises a getter and / or a desiccator.

73. The method according to any of claims 71-72, wherein 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.17874. The method according to any of the preceding claims, wherein the solidified 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, TeCU, TeCh, and / or TesC75. The method according to any of the preceding claims, wherein the solidified seal material (22) comprises Bi2Os in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

76. A cover (20) for use during sealing a through hole (10, 10a) of an evacuated gap (6) of a vacuum insulating glass (VIG) 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 glass solder material (22), wherein the glass transition temperature of the glass solder material (22) is lower than the glass transition temperature of the covering body (21), wherein said cover (20) is manufactured according to the method of any of the preceding claims.

77. Cover (20) according to claim 76, wherein solidified seal material (22) is substantially non-crystalline, such as wherein the crystallinity is less than 30%, such as less than 20%, such as less then 10%.

78. Cover (20) according to any of claims 76-77, wherein the solidified seal material (22) comprises or consists of a low-temperature glass solder material.

79. Cover (20) according to any of claims 76-78, wherein the solidified seal 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.

80. Cover (20) according to claim 79, wherein the solidified 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, TeCU, TeCh, and / or TesCL.17981. Cover (20) according to claim 80, wherein the solidified seal material (22) comprises more tellurium oxide than vanadium oxide by weight.

82. Cover (20) according to any of claims 79-81 , wherein the solidified seal material (22) comprises Bi2Os in combination with one or more of the following metal oxides: SiC>2, B2O3, ZnO, and / or AI2O3.

83. Cover (20) according to any of claims 79-82, wherein the solidified seal material (22) comprises B2O3 in combination with one or more of the following metal oxides: SiC>2, Bi2C>3, ZnO, and / or AI2O3.

84. Cover according to claim 79, wherein the solidified seal material (22) comprises SnO and P2O5.

85. Cover according to any of claims 79-84, wherein the solidified seal material (22) comprises less than 1 wt-%, such as less than 0.5 wt-%, such as less than 0.1 wt- % of Pb.

86. A cover (20) according to any of claims 79-85, wherein the seal material moreover comprises a primer layer (28), such as a single primer layer or a multilayer primer layer arranged between the solder material (22) and the covering body (21).

87. Cover (20) according to claim 86, wherein the primer layer (28) is arranged so as to cover substantially the whole major surface (21a) of the covering body (21), and / or wherein the primer layer (28) is arranged so as to cover the same area of the major surface (21a) of the covering body (21) as is covered by the seal material (22).

88. Cover (20) according to claim 86, wherein the primer layer (28) is arranged so as to cover 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).18089. Cover (20) according to any of claims 86-88, wherein the primer layer (28) 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 (28) 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 (28) has a height of no more than 100 pm, such as no more than 80 pm, such as no more than 50 pm.

90. Cover (20) according to any of claims 86-89, 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), and / or wherein the primer layer (28) 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 (21) and higher than the softening point, such as Littleton softening point, of the solder material (22).

91. Cover (20) according to any of claims 86-90, wherein the primer layer (28) covers between 50% and 100%, such as between 70% and 100%, such as between 70% and 93% of the major surface (21a) of the covering body (21), and / or wherein the primer layer (28) 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 (22).

92. A method of manufacturing a vacuum insulated glass (VIG) unit (1), the method comprising:• providing a vacuum insulated glass (VIG) unit assembly (1), wherein the vacuum insulated glass (VIG) unit assembly (1) comprises: o a first glass sheet (2) and a second glass sheet (3), o 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), o 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 major181 surface (2a) and a second, oppositely directed, major surface (2b) of the first glass sheet (2),• providing a cover (20) comprising a covering body (21) and a solidified seal material (22), wherein the solidified seal material (22) comprises glass solder material, wherein the seal material (22) is attached to a surface (21a) of the covering body (21),• arranging the 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 heated 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).

93. Method according to claim 92, wherein said provided cover is a cover (20) according to any one of claims 75-91 and / or a cover manufactured by means of a method according to any of claims 1-75.

94. Method according to any of claims 92-93, wherein the method comprises the step of collecting an obtained cover (20) from a controlled, such as reduced, such as sealed, atmosphere environment of a container, such as according to any of claims 72-74.

95. Method of according to any of claims 92-94, 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 smaller182 diameter portion (10a), wherein said arranging of the cover (20) comprises arranging the solidified seal material (22) opposite to, such as so as to support on, the step surface (10s, 2sp) so that the covering body (21) is arranged in the larger diameter portion (10b) and covers the smaller diameter portion (10a).

96. Method according to claim 95, wherein the step of arranging the cover (20) in the larger diameter portion (10b) of the through hole (10) in the first glass sheet (2) provides a maximum distance between a side surface (21c) of the covering body (21) and a side surface (10bs) of the larger diameter portion (10b) of at least 2%, such as at least 4%, such as at least 6% of a width of the covering body (21) surface (21a) comprising the solder material (22), and / or wherein the step of arranging the cover (20) in the larger diameter portion (10b) of the through hole (10) in the first glass sheet (2) provides a maximum distance between a side surface (21c) of the covering body (21) and a side surface (10bs) of the larger diameter portion (10b) of at least 0.2 mm, such as at least 0.4 mm, such as at least 0.5 mm, and / or wherein the step of arranging the cover (20) in the larger diameter portion (10b) of the through hole (10) in the first glass sheet (2) provides a maximum distance between a side surface (21c) of the covering body (21) and a side surface (10bs) of the larger diameter portion (10b) of at least 10%, such as at least 15%, such as at least 20% of the diameter of the smaller diameter portion (10a) of the through hole.

97. Method according to any of claims 92-96, wherein the step of arranging the cover (20) in the larger diameter portion (10b) of the through hole (10) in the first glass sheet (2) provides a space between a side surface (21c) of the covering body (21) and a side surface (10bs) of the larger diameter portion (10b), wherein said space has a total area as seen from above of at least 4.0 mm2, such as at least 6.0 mm2, such as at least 10.0 mm2, and / or wherein the step of arranging the cover (20) in the larger diameter portion (10b) of the through hole (10) in the first glass sheet (2), provides a space between a side surface (21c) of the covering body (21) and a side surface (10bs) of the larger diameter portion (10b), wherein said space has a total area as seen from above of at least 50%, such as at least 75%, such as at least 90% of the area of the smaller diameter portion (10a) of the through hole (10).18398. Method according to any of claims 92-97, wherein the step of heating the solidified seal material (22) comprises raster scanning a laser beam across the surface (22a) of the solidified solder material that faces away from the covering body (21).

99. Method according to claim 98, wherein 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.

100. Method according to any of claims 98-99, wherein 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.

101. Method according to any of claims 98-100, wherein 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.

102. A vacuum insulated glass (VIG) unit (1) manufactured according to any of claims 92-101.

103. A building window comprising a vacuum insulated glass (VIG) unit (1) according to claim 102.

104. Use of a cover according to any one of claims 75-91 for sealing an evacuated gap (6) of a vacuum insulating glass (VIG) unit (1).

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