Two-stage airtight seal and its manufacturing process

Abstract

A vacuum glass assembly has first and second spaced-apart non-metallic substrates connected to each other by a sealing element to form an evacuable interior space therebetween. The sealing element is formed by: joining a metal bridging element to at least one of the substrates using cold welding to form a first-level seal; forming a second-level seal at least partially in contact with the first-level seal. The sealing element is configured to hermetically isolate the interior space from the surrounding environment, and both the first-level seal and the second-level seal contribute to the hermeticity of the sealing element.

Description

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with U.S. Government support under SBIR assistance agreement DE-SC0017841 awarded by the U.S. Department of Energy. The U.S. Government has certain rights in this invention.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to U.S. Provisional Patent Application No. 63 / 038,102, filed on June 11, 2020, the entire contents of which are incorporated herein by reference. Field of the Invention

[0005] The present invention relates to a method for creating a two-stage hermetic sealing element for an envelope having an interior region isolated from the environment. Background Art

[0006] Many existing evacuated glazing assemblies (e.g., vacuum insulated glass ("VIG") assemblies) include two or more panels (e.g., glass panes) that are separated from each other by a certain space. Temperature differences across the glass assembly can significantly affect the structure of the assembly and, in some cases, cause the assembly to fail. For example, when an evacuated glazing assembly is installed in the exterior wall of a temperature-controlled and / or insulated building, the temperature of the outer panel is generally close to the outside air temperature (contracting when exposed to cold and expanding when exposed to heat). The inner panel is generally maintained at a relatively constant temperature consistent with the inside air temperature. Movement (i.e., contraction or expansion) of the outer panel relative to the inner panel is called "differential pane movement", and excessive differential pane movement may cause the evacuated glazing assembly to fail due to cracking, seal failure, or other mechanisms. Summary of the invention

[0007] One type of sealing element that can be used to seal between the plates of the vacuum glass assembly includes a metal bridging element (e.g., a metal foil) that is welded to a metal adhesive layer deposited on the plates. An example of such a hermetic sealing element is provided in U.S. Provisional Application No. 62 / 936,140, ​​filed on November 15, 2019, the entire contents of which are incorporated herein by reference.

[0008] Hermetic seals may fail (i.e., leak) via a variety of different mechanisms, including: micro-leak paths along the interface between the metal bridging element and the glass, defects in the metal bridging element (e.g., scratches, wrinkles, microstructural damage, perforations through or along the edge of the weld, joints between discontinuous segments of the metal bridging element, etc.), defects in the glass (e.g., scratches), defects due to uncontrolled process parameter variations (e.g., due to "tramp" metal adhering to the weld tip), and misalignment of weld segment overlaps. While these failure mechanisms can be reduced using tightly controlled manufacturing processes, there is still a need for a seal configuration that can provide a more reliable hermetic seal in a cost-effective manner.

[0009] In one aspect, the present invention provides a vacuum glass assembly having a first substrate and a second substrate spaced apart, the first substrate and the second substrate being connected to each other by a sealing element to form a vacuumable interior space therebetween. The sealing element is formed by: joining a metal bridging element to at least one of the substrates using cold welding to form a first-level seal; forming a second-level seal at least partially in contact with the first-level seal. The sealing element is airtight and is configured to effectively airtightly isolate the interior space from the surrounding environment.

[0010] In another aspect, the present invention provides a vacuum glass assembly, the vacuum glass assembly comprising a first substrate, a second substrate spaced apart from the first substrate to define an interior space therebetween, and a sealing element disposed between the first substrate and the second substrate to hermetically isolate the interior space from the surrounding environment. The sealing element comprises a first-level seal formed by a cold welding joint between a metal bridging element and the first substrate, and a second-level seal at least partially in contact with the first-level seal.

[0011] In another aspect, the present invention provides a method for forming a sealing element for making a hermetic seal between two substrates of a vacuum glass assembly. The method includes: joining a metal bridging element to each of the two substrates to form a first hermetic seal level; applying a sealing material at least partially in contact with the first hermetic seal level; and heating the sealing material to form a second hermetic seal level.

[0012] Other features and aspects of the present invention will become apparent from the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a partial cross-sectional view of an exemplary vacuum glass assembly including an interior space and a sealing element isolating the interior space from a surrounding environment.

[0014] Figure 2 for Figure 1 A partial cross-sectional view of the first and second stages of a sealing element bonded to a substrate.

[0015] Figure 3 FIG. 1 is a partial cross-sectional view of a first stage and a second stage of a sealing element according to another embodiment.

[0016] Figure 4 FIG. 1 is a partial cross-sectional view of a first stage and a second stage of a sealing element according to another embodiment.

[0017] Figure 5 FIG. 1 is a partial cross-sectional view of a first stage and a second stage of a sealing element according to another embodiment.

[0018] Figure 6 FIG. 1 is a partial cross-sectional view of a first stage and a second stage of a sealing element according to another embodiment.

[0019] Figure 7 for Figure 1 A partial cross-sectional view of a vacuum glass assembly including a sealing element according to another embodiment.

[0020] Figure 8 for Figure 1 A partial cross-sectional view of a vacuum glass assembly including a sealing element according to another embodiment.

[0021] Fig. 9 Photographs of first and second stages of a sealing element embodying aspects of the present invention.

[0022] Fig.10 is a top view showing the bonding of the foil to the substrate.

[0023] Fig.11 FIG. 4 is a flow chart of a sealing process according to an embodiment of the present invention.

[0024] Before describing in detail any embodiment of the present invention, it should be understood that the present invention is not limited in its application to the details of construction and arrangement set forth in the following description or shown in the above drawings. The present invention is capable of other embodiments and can be implemented or carried out in various ways without significantly departing from the spirit of the present invention.

[0025] definition

[0026] As used herein, the term "pane" refers to a glass element used as a wall element or substrate in a flat hermetically-sealed enclosure assembly.

[0027] "Differential pane movement" refers to the relative pane movement between two adjacent panes that occurs when the temperature of one pane changes relative to the temperature of the other pane. "Differential pane movement" may also refer to the relative pane movement that occurs under mechanical or other influences, such as impact during handling or use.

[0028] "Hermeticity" or "level of hermeticity" refers to a measure of the maximum leak rate that a seal can achieve, measured, for example, in standard cubic centimeters of helium per second per centimeter of seal length ("sccs / cm") or equivalent. In general, higher hermeticity corresponds to lower leak rate values, and vice versa.

[0029] "Hermetic" means that the seal can achieve a hermeticity suitable for the application or specified by the application. It should be recognized that each level in a multi-level seal (such as the sealing levels described and shown herein) can be described as hermetic, which does not mean that each level of hermeticity is the same.

[0030] The term "highly-malleable" refers to an object or material having a yield stress of no greater than 10,000 psi (eg, no greater than 5,500 psi).

[0031] The term "solid state" with respect to welding or coating refers to a joining process that does not involve melting of the materials being joined.

[0032] The term "cold welding" refers to a solid-state process used to join two or more components.

[0033] The term "sonotrode" refers to a vibrating tool that imparts translational motion to the components of the substrates to be welded via an ultrasonic joining device.

[0034] The term "mechanical horn (mechtrode)" or "mechanized horn (mechatrode)" refers to a mandrel or other end-effector tool used in a process for solid state bonding or coating of materials by relative motion under pressure, which process does not generally involve ultrasonic vibrations.

[0035] With respect to the location of a first feature relative to a second feature on a component having a generally planar shape, the term "inboard" refers to the location of the first feature on a side of the second feature that is closer to the centroid of the generally planar shape.

[0036] With respect to the location of a first feature relative to a second feature on a component having a generally planar shape, the term "outboard" refers to the location of the first feature on a side of the second feature further from the centroid of the generally planar shape.

[0037] The term "bridge element" means an element that is bonded to a substrate and forms a part of a hermetic sealing element that isolates an interior space from the environment. DETAILED DESCRIPTION

[0038] Figure 1 A portion of an exemplary vacuum glass assembly 10 (e.g., a window assembly configured for installation in a building exterior wall) is shown, the vacuum glass assembly including a first substrate 14 (e.g., a first panel) and a second substrate 16 (e.g., a second panel) spaced apart from the first substrate 14 to define an interior space 18 (also referred to as an evacuable gap or interior region) to be sealed and isolated from the surrounding environment of the vacuum glass assembly 10. One or more spacers 20 formed of an incompressible or substantially incompressible material (e.g., a composite material, plastic, glass, metal, etc.) may be positioned in the interior space 18 between the first and second substrates 14, 16 to maintain a consistent gap between the first and second substrates 14, 16. In the illustrated embodiment, the first and second substrates 14, 16 are non-metallic (e.g., glass, such as annealed glass or tempered glass). In other embodiments, one or both of the first and second substrates 14, 16 may be metal. A sealing element 22 is attached to each of the first and second substrates 14, 16 to hermetically isolate the interior space from the surrounding environment.

[0039] Continue to refer Figure 1, the sealing element 22 includes a metal bridging element 30 and a sealing material 34. The bridging element 30 may be formed of one or more layers of metal foil (e.g., aluminum foil). In the illustrated embodiment, the bridging element 30 is formed of two segments 30a, 30b, each of which is directly joined to the respective first and second substrates 14, 16 via a solid-state welding process (e.g., a friction welding process using an ultrasonic horn) to form a weld 36. In the illustrated embodiment, the two segments 30a, 30b are connected to each other by a connecting weld 42 (e.g., a fusion weld, such as a laser weld, a MicroTIG weld, a resistance weld, etc., or the weld 42 may include a solid-state weld). In other embodiments, the segments 30a, 30b of the bridging element 30 may be integrally formed from a piece of material, or the segments 30a, 30b may be connected together in other ways.

[0040] refer to Figure 2 , the bridging element 30 is attached to the first substrate 14 by a weld 36. The bridging element 30 extends through the interior space 18 along the outer edge boundary of the interior space 18 (i.e., between the first and second substrates 14, 16) to hermetically seal the interior space 18. The weld 36 forms a first seal level 38 (also referred to as a first stage seal or primary seal or an outer seal level) of the sealing element 22. The first stage seal 38 is airtight and also provides a structural connection between the bridging element 30 and the first substrate 14. That is, the first stage seal 38 is configured to resist shear forces generated due to thermal expansion or differential plate movement. In some embodiments, the structural connection between the bridging element 30 and the first substrate 14 formed by the first stage seal 38 has a shear strength greater than the tensile strength of the bridging element 30 itself.

[0041] refer to Figure 3 In some embodiments, the sealing element 22 further includes an interlayer 37, which can be made of a metal (e.g., aluminum) or an inorganic material. In particular, the interlayer 37 is formed as a coating that is deposited or otherwise disposed on an edge portion (e.g., along the periphery) of the first substrate 14. For example, in some embodiments, the interlayer 37 can be deposited on the first substrate 14 using a mechanical horn. The bridging element 30 is attached to the first substrate 14 on the interlayer 37 to form a weld 36 (e.g., by a solid-state welding process, such as a friction welding process using an ultrasonic horn), thereby forming a first-level seal 38. The interlayer 37 can increase the mechanical strength and / or airtightness of the first-level seal 38.

[0042] refer to Figures 2 to 3 , the sealing material 34 is at least partially in contact with the first stage seal 38 and forms a second seal stage 40 (also referred to as a second stage seal or secondary seal or an inner seal stage) of the sealing element 22. The sealing material 34 can be composed of solder glass, metal solder, or other materials suitable for bonding to the bridge element 30 and / or the first substrate 14 and forming a seal with a desired airtightness. Generally, the airtightness of a defective first seal stage 38 is less than (i.e., leaks more) than the airtightness of the corresponding second seal stage 40. Conversely, the airtightness of a non-defective first seal stage 38 is generally similar to the airtightness of the corresponding second seal stage 40. Accordingly, the airtightness of the combined two-stage sealing element 22 is in the same order as the airtightness of the second stage seal 40.

[0043] In some embodiments, the sealing material 34 can be an organic sealing material. In such embodiments, the organic sealing material is preferably an organic sealing material with low outgassing and low permeation rate (low-outgassing and low-permeation rate organic sealing material). In the past, organic sealing materials could not provide a lasting airtight sealing performance in a passive (i.e., non-actively pumped) vacuum glass assembly. However, the two-stage sealing element 22 allows the second sealing level 40 to use an organic sealing material because the airtight first-stage sealing 38 minimizes the exposure of the second-stage sealing 40 to the external environment. In other words, the first-stage sealing 38 reduces the potential gas permeation through the second-stage sealing member 40, which allows the second-stage sealing 40 to use a wider variety of materials without affecting the overall airtightness of the sealing element 22.

[0044] In the illustrated embodiment, the sealing material 34 covers the entire primary seal 38. In other embodiments, the sealing material 34 can be disposed in contact with only a portion of the primary seal 38 (e.g., the secondary seal 40 can be positioned against the inside edge of the primary seal 38, covering the interface bond between the primary seal 38 and the first substrate 14). The sealing material 34 can be bonded to one or both of the first substrate 14 and the bridging element 30.

[0045] The melting and / or curing temperature of the sealing material 34 is lower than the melting temperatures of the first and second substrates 14, 16 and other portions of the vacuum glass assembly 10. In some embodiments, the sealing material 34 is melted and / or cured by heating at least a portion of the vacuum glass assembly 10 containing the sealing material 34 using a heating device to bond with the first substrate 14 and the bridge element 30. In some embodiments, the entire vacuum glass assembly 10 may be heated using a heating device (e.g., an oven) to melt and / or cure the sealing material 34, thereby forming a second-level seal 40.

[0046] refer to Figure 2 Because the primary seal 38 is located outside the secondary seal 40, the structural connection formed by the weld 36 between the bridge element 30 and the first and second substrates 14, 16 substantially bears all shear stresses that may be applied to the sealing element 22. That is, if a force F is applied to the sealing element 22 (e.g., due to uneven thermal expansion and / or differential plate movement), substantially all of the shear stress will be borne by the high-strength weld 36 of the primary seal 38, rather than by the secondary seal 40. Because the secondary seal 40 is shielded from mechanical stresses by the primary seal 38, the airtightness of the secondary seal 40 can be maintained for a longer period of time. However, in other embodiments, the secondary seal 40 can be at least partially located outside the primary seal 38.

[0047] Figures 4 to 6 Various configurations of the secondary seal 40 are shown. For example, the secondary seal 40 may be formed by melting the inner edge of the bridging element 30 ( Figure 4 ) and / or the middle portion of the bridging element 30 in the region of the primary seal 38 ( Figure 5 In such embodiments, the second level seal 40 may be formed by laser welding. Figure 6 The secondary seal 40 may be formed by cold welding the inner edge of the bridge element 30 and / or the middle portion of the bridge element 30 within the primary seal area. Figures 4 to 6 The embodiment of the secondary seal 40 shown in FIG. 4 enables the secondary seal 40 to be formed before or after the primary seal 38 , providing additional flexibility in the manufacturing process.

[0048] although Figures 2 to 6 Only the first substrate 14 is shown, but the sealing element 22 also includes substantially identical first and second sealing stages ( Figure 1 ). Back to Figure 1 , a connecting weld 42 may be applied to the exterior of the bridge element 30 to join the segments 30a, 30b of the bridge element 30 together. Figure 7In another embodiment of a similar vacuum glass assembly 10A, the connecting weld 42 can be replaced with a connecting material 43 that joins the segments 30a, 30b of the bridge element 30. For example, the connecting material 43 can be a metal solder or a solder glass material. Using the connecting material 43 instead of the connecting weld 42 can provide lower heat input into the sealing element 22 and the first and second substrates 14, 16 during the application process. In another embodiment, the connecting material 43 can be an adhesive.

[0049] refer to Figure 8 In another embodiment of a similar vacuum glass assembly 10B, the bridge element 30 is formed by a single substantially planar section. Figure 1 and Figure 7 In the embodiment shown, the connecting weld 42 and the connecting material 43 are respectively shown. In the embodiment shown, the peripheral edges of the first substrate 14 and the second substrate 16 are offset from each other, so that the outer edge of the first substrate 14 is spaced apart from the outer edge of the second substrate 16. This offset arrangement provides a path for forming the outer sealing level 38 and the inner sealing level 40.

[0050] Fig.11 An exemplary four-step process for forming a two-stage sealing element (such as the one described above) is shown. Figures 1 to 8 The embodiment of the sealing element 22 described above is used to place and connect the sealing element 22 relative to the first and second substrates 14 and 16. It can be understood that Fig.11 A general flow is covered, and additional steps may be incorporated into the process to facilitate the formation of the sealing element 22, and the placement and attachment of the sealing element 22 to the first and second substrates 14, 16. The general flow includes: i) preparing a non-metallic substrate (step S100); ii) bonding a metallic bridging element to the substrate to form a first sealing level (step S104); iii) applying a sealing material at least partially in contact with the first sealing level to form a second sealing level (step S108); and iv) further processing (step S112). These major steps may be performed sequentially, or one or more steps may be performed simultaneously.

[0051] In a first major step (step S100), the first and second substrates 14, 16 are prepared, which may include cleaning the first and second substrates 14, 16 (e.g., by plasma cleaning in some embodiments) and / or placing an interlayer (e.g., interlayer 37; Figure 3) is added to each of the first and second substrates 14, 16. In some embodiments, the interlayer 37 is applied to the first and second substrates 14, 16 using a process or method that does not include an oven for heating the first and second substrates 14, 16 and does not use a vacuum chamber (i.e., a no-oven, no-vacuum chamber process). For example, in some embodiments, a malleable metal (e.g., aluminum) is applied to a non-metallic substrate using friction surfacing. Friction surfacing includes: pressing a metal consumable (e.g., a mechanized welding head) formed of a malleable metal onto the surface of a non-metallic substrate, and moving one or both of the metal consumable and the substrate (i.e., achieving relative movement) to deposit or transfer the malleable metal onto the surface of the non-metallic substrate, thereby forming a metal layer that serves as part of the sealing element. In some configurations, a stabilizing gas (e.g., argon) can be used to expel oxygen during the friction surfacing process.

[0052] In the second main step (step S104), the metal bridge element 30 is directly bonded to each of the first and second substrates 14, 16 by a cold welding process, or bonded to an optional interlayer 37 and then bonded to the first and second substrates 14, 16. In particular, the ultrasonic horn of an ultrasonic seam welder can be used to weld the metal bridge element 30 and form a weld 36 defining a first sealing level 38.

[0053] In a third major step (step S108), a sealing material 34 is applied at least partially in contact with the first sealing level 38. In some embodiments, the sealing material 34 is provided as a powder (e.g., powdered solder glass) that is distributed on the first sealing level 38. In some embodiments, the sealing material 34 may be provided as a gel or the like. In other embodiments (e.g., Figures 4 to 6 ), the sealing material 34 may be part of the metal bridging element 30 itself, which is melted or otherwise transformed by laser welding, cold welding or other similar processes to form the second sealing level 40.

[0054] Finally, in a fourth major step (step S112), further processing may be performed, such as melting and / or curing the sealing material 34 (e.g., using an oven or other heat source) to form a second sealing level 40. Additional processing may include evacuating the interior space 18. Further processing of the assembly may take a variety of forms, including firing a getter in the interior space 18, and in some cases, a secondary welding or sealing step may be required to ensure that the interior space can be evacuated or permanently sealed.

[0055] Compared to a single-stage sealing element, the two-stage sealing element 22 according to the embodiments described and illustrated herein has many advantages. For example, if the airtightness of the first-stage seal 38 is degraded due to any of a variety of different mechanisms such as microleakage, perforation through or along the edge of a weld, defects in the metal bridging element 30 (e.g., scratches, wrinkles, etc.), defects in the first and second substrates 14, 16 (e.g., scratches), and misalignment, the second-stage seal 40 provides a redundant or secondary airtight seal to maintain the integrity of the sealing element 22. In this way, the first-stage seal 38 can be manufactured in a lower cost manner (e.g., with lower manufacturing tolerances, less quality control testing, etc.) while helping to achieve effective overall airtight sealing performance. In some embodiments, the two-stage sealing element 22 can also provide a longer service life for the sealed product. As Fig. 9 As shown, it should be appreciated that the secondary seal 40 may also repair (ie, eliminate leaks) defects 50 that may exist in the primary seal 38 (eg, by filling voids, microcracks, etc.).

[0056] Because the secondary seal 40 is at least partially located inside the primary seal 38 in some embodiments, gases that may be trapped therebetween or at the interface of the bridge element 30 with the first and second substrates 14, 16 cannot communicate with the interior space 18 to be evacuated. This can advantageously speed up the evacuation of the interior space 18. In addition, when solder glass is used as the sealing material 34, the secondary seal 40 can dissolve the portions of common coatings (such as low-E coatings) on the first and second substrates 14, 16 adjacent thereto, providing a barrier to prevent corrosion processes that may occur along the coatings, thereby protecting the evacuated interior space 18.

[0057] An important advantage of the two-stage sealing element 22 according to the embodiments described and illustrated herein is that the metal bridging element 30 is in both physical and bonded contact with the non-metallic substrate. This improves sealing performance.

[0058] In some embodiments, the two-stage sealing element 22 can provide a convenient chamber for containing a getter ribbon or getter particles that remove residual gas from the evacuated interior space. Such a chamber can inhibit the migration of getter material into visible areas of the product after the getter reacts.

[0059] In some embodiments (e.g., Figure 1), the second level seal 40 may maintain a gap between opposing portions of the metal bridging element 30, thereby inhibiting heat transfer between the two first and second substrates 14, 16 due to conduction through the metal bridging element 30.

[0060] In some embodiments, the two-stage sealing element 22 advantageously allows the use of foil strip segments to form the metal bridging element 30 (eg, Fig.10 2 (shown), rather than using a full sheet of foil to form the metal bridging element, which would subsequently need to be trimmed on the inside of the sealing element 22. Because the foil strips are connected using welds 54 at corners or other transitions, the first-stage seal 38 is more likely to have defects, resulting in a localized reduction in the airtightness in the area of ​​the welds 54. The second-stage seal 40 can seal any such defects to improve the overall airtightness of the sealing element.

[0061] Although Figures 1 to 8 Portions of an exemplary product including a two-stage sealing element are shown, but it is understood that other products may also include the sealing element (eg, a flat panel display). Therefore, the invention described and claimed herein should not be construed as covering only window assemblies.

[0062] It should be understood that, without departing from the spirit or features of the present invention, the present invention may be embodied in other specific forms, or include a combination of the embodiments described herein. Although specific embodiments have been illustrated and described, other modifications may also be made without seriously departing from the spirit of the present invention.

[0063] Various features of the invention are set forth in the following claims.

Claims

1. A vacuum glass assembly, comprising a first substrate and a second substrate spaced apart from each other, the first substrate and the second substrate being connected to each other by a sealing element to form a vacuumable inner space therebetween, wherein the sealing element is formed by: bonding a metallic bridging element to at least one of the substrates using a cold weld bond to form a primary seal; and forming a secondary seal, the secondary seal at least partially contacting the first primary seal, the secondary seal being located at least partially laterally inward from the first primary seal such that the secondary seal is at least partially directly bonded to at least one of the substrates; wherein the second stage seal is used to hermetically seal the first stage seal; The sealing element is configured to isolate the inner space from the surrounding environment in an airtight manner. 2 . The vacuum glass assembly of claim 1 , wherein forming the second-level seal comprises applying a sealing material at least partially in contact with the first-level seal. 3 . The vacuum glass assembly according to claim 2 , wherein the sealing material comprises solder glass or metal solder. The vacuum glass assembly according to claim 2 , wherein the sealing material comprises an organic sealing material. 5 . The vacuum glass assembly of claim 2 , wherein forming the second level seal further comprises heating the vacuum glass assembly. 6 . The vacuum glass assembly of claim 1 , wherein forming the second level seal comprises welding at least a portion of the first level seal.

7. The vacuum glass assembly of claim 1, wherein the primary seal is formed by a vibrating ultrasonic horn in contact with the metal bridging element. 8 . The vacuum glass assembly of claim 1 , wherein the metal bridging element comprises a first segment bonded to the first substrate and a second segment bonded to the second substrate.

9. The vacuum glass assembly of claim 8, wherein the first section is welded to the second section. 10 . The vacuum glass assembly according to claim 8 , wherein the first segment is joined to the second segment by a connecting material.

11. A vacuum glass assembly, comprising: a first substrate; a second substrate spaced apart from the first substrate to define an interior space therebetween; A sealing element, the sealing element being disposed between the first substrate and the second substrate to hermetically isolate the internal space from the surrounding environment, wherein the sealing element comprises: a metal bridging element extending between the first substrate and the second substrate; a primary seal formed by a cold welded joint between the metallic bridging element and the first substrate, the primary seal having an inner edge extending along the metallic bridging element and the first substrate, and A second primary seal is at least partially in contact with the first primary seal along an inside edge of the first primary seal. 12 . The vacuum glass assembly of claim 11 , wherein the second-level seal comprises an organic sealing material applied to the first-level seal to seal the first-level seal. 13 . The vacuum glass assembly according to claim 11 , wherein the first level seal comprises a metal interlayer or an inorganic interlayer between the metal bridging element and the first substrate.

14. The vacuum glass assembly of claim 11, wherein the second stage seal comprises a sealing material applied to at least partially contact the first stage seal.

15. The vacuum glass assembly of claim 11, wherein the secondary seal comprises a welded portion of the metal bridging element.

16. The vacuum glazing assembly of claim 11, wherein the first level seal forms a structural connection between the metal bridging element and the first substrate, the shear strength of the structural connection being greater than the tensile strength of the metal bridging element.

17. The vacuum glass assembly of claim 11, wherein both the first-stage seal and the second-stage seal contribute to the airtightness of the sealing element.

18. The vacuum glass assembly of claim 11, wherein the second level seal is configured to fill defects in the first level seal. The vacuum glass assembly according to claim 11 , wherein the first substrate is made of a non-metallic material. 20 . The vacuum glass assembly according to claim 19 , wherein the second substrate is made of a non-metallic material.

21. A method of forming a sealing element for hermetically sealing between two substrates of a vacuum glass assembly, the method comprising: bonding a metal bridging element to each of the two substrates through a corresponding bonding portion to form a first hermetic sealing level of the vacuum glass assembly; applying a sealing material at least partially in contact with the first hermetic sealing level along an inside edge of one or both of the joints to hermetic seal the first hermetic sealing level; as well as The sealing material is heated to form a second hermetic sealing level and hermetically seal the first hermetic sealing level.

22. The method of claim 21, wherein the joining of the metal bridging element to each of the two substrates through the respective joining portions is performed by cold welding.

23. The method of claim 21, wherein the sealing material comprises at least one selected from the group consisting of solder glass, metal, and an organic sealing material.

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