Two-stage hermetic seal and process of making same
An evacuated glazing assembly has first and second spaced-apart, non-metal substrates connected to each other by a seal element to form an evacuable interior space therebetween. The seal element is formed by bonding a metallic bridge element to at least one of the substrates by cold welding to form a first stage seal and forming a second stage seal at least partially in contact with the first stage seal. The seal element is configured to hermetically isolate the interior space from the surrounding environment, and both the first stage seal and the second stage seal contribute to the hermeticity of the seal element.
1 . An evacuated glazing assembly having first and second spaced-apart substrates connected to each other by a seal element to form an evacuable interior space therebetween, wherein the seal element is formed by:
bonding a metallic bridge element to at least one of the substrates using cold welding to form a first stage seal; and
forming a second stage seal in contact with and disposed at least partially over the first stage seal, the second stage seal further positioned partially laterally inward of the first stage seal such that the second stage seal is partially bonded directly to the at least one of the substrates,
wherein the second stage seal is configured to hermetically seal the first stage seal, and
wherein the seal element is configured to hermetically isolate the interior space from the surrounding environment.
2 . The evacuated glazing assembly of claim 1 , wherein forming the second stage seal includes applying a sealing material partially in contact with the first stage seal.
3 . The evacuated glazing assembly of claim 2 , wherein the sealing material includes solderglass.
4 . The evacuated glazing assembly of claim 2 , wherein the sealing material includes metal solder.
5 . The evacuated glazing assembly of claim 2 , wherein the sealing material includes an organic sealing material.
6 . The evacuated glazing assembly of claim 2 , wherein forming the second stage seal further includes heating the evacuated glazing assembly.
7 . The evacuated glazing assembly of claim 1 , wherein forming the second stage seal includes welding at least a portion of the first stage seal.
8 . The evacuated glazing assembly of claim 1 , wherein cold welding includes contacting the metallic bridge element with a vibrating sonotrode.
9 . The evacuated glazing assembly of claim 1 , wherein the metallic bridge element includes a first segment bonded to the first substrate, and a second segment bonded to the second substrate.
10 . The evacuated glazing assembly of claim 9 , wherein the first segment is welded to the second segment.
11 . The evacuated glazing assembly of claim 9 , wherein the first segment is bonded to the second segment using a connecting material.
12 . An evacuated glazing assembly comprising:
a first substrate;
a second substrate spaced from the first substrate to define an interior space therebetween;
a seal element disposed between the first substrate and the second substrate to hermetically isolate the interior space from a surrounding environment, wherein the seal element includes:
a metallic bridge element at least partially located between the first substrate and the second substrate, the metallic bridge element having an elongated section extending along a peripheral side of the evacuated glazing,
a first stage seal defined by a cold-welded bond between the metallic bridge element and the first substrate, the first stage seal having an inboard edge extending along the elongated section of the metallic bridge element and the first substrate, and
a second stage seal in contact with the first stage seal along the inboard edge, and the second stage seal further at least partially covering the first stage seal.
13 . The evacuated glazing assembly of claim 12 , wherein the first stage seal includes a metallic or inorganic interlayer between the metallic bridge element and the first substrate.
14 . The evacuated glazing assembly of claim 12 , wherein the second stage seal includes a sealing material configured to be heated to form the second stage seal and applied at least partially in contact with the first stage seal.
15 . The evacuated glazing assembly of claim 12 , wherein the second stage seal includes a welded portion of the metallic bridge element different from the cold-welded bond.
16 . The evacuated glazing assembly of claim 12 , wherein the first stage seal defines a structural connection between the metallic bridge element and the first substrate having a shear strength greater than a tensile strength of the metallic bridge element.
17 . The evacuated glazing assembly of claim 12 , wherein both the first stage seal and the second stage seal contribute to the hermeticity of the seal element.
18 . The evacuated glazing assembly of claim 12 , wherein the second stage seal is configured to fill imperfections in the first stage seal.
19 . The evacuated glazing assembly of claim 12 , wherein the first substrate is made of a non-metallic material.
20 . The evacuated glazing assembly of claim 19 , wherein the second substrate is made of a non-metallic material.
21 . A method of forming a seal element for hermetically isolate an interior space between a first substrate and a second substrate of an evacuated glazing assembly from a surrounding environment, the method comprising:
bonding a metallic bridge element to each of the first substrate and the second substrate via respective cold-welds to form corresponding first stage seals between the metallic bridge element, each of the first stage seals having an inboard edge extending along the metallic bridge element and the first and second substrates, respectively;
applying a sealing material at least partially in contact with and along the inboard edge of each of the first stage seals, the sealing material further disposed at least partially over each of the first stage seals; and
heating the sealing material to form a second stage seal.
22 . The method of claim 21 , wherein the sealing material includes at least one selected from a group consisting of: solderglass, metal, and organic sealing material.