Welding/sealing glass-enclosed space in a vacuum

• US 5,489,321 A
• Filed: 07/14/1994
• Issued: 02/06/1996
• Est. Priority Date: 07/14/1994
• Status: Expired due to Fees

• Current Assignee: Midwest Research Institute
• Original Assignee: Midwest Research Institute
• Inventors: Tracy, C. Edwin, Benson, David K.
• Primary Examiner(s): Lacey, David L.
• Assistant Examiner(s): VINCENT, SEAN E
• Application Number:
  US08/274,788
• Time in Patent Office: 572 Days
• Field of Search: 65/36, 65/40, 65/43, 65/152, 156/89, 156/99, 156/102, 156/104, 156/272.8, 156/290, 156/299, 156/272.2
• US Class Current: 65/43
• CPC Class Codes: C03B 23/245 Hollow glass sheets
• CPC Class Codes: C03C 27/06 Joining glass to glass by processes other than fusing fusing C03B23/20; units for use as elements for closing wall or like openings and comprising two or more parallel glass panes in spaced relationship, the panes being permanently secured together E06B3/66
• CPC Class Codes: E06B 3/6612 Evacuated glazing units
• CPC Class Codes: Y02A 30/249 Glazing, e.g. vacuum glazing
• CPC Class Codes: Y02B 80/22 Glazing, e.g. vaccum glazing

Abstract

A method of welding and sealing the edges of two juxtaposed glass sheets together to seal a vacuum space between the sheets comprises the steps of positioning a radiation absorbant material, such as FeO, VO₂, or NiO, between the radiation transmissive glass sheets adjacent the edges and then irradiating the absorbant material, preferably with a laser beam, through at least one of the glass sheets. Heat produced by the absorbed radiation in the absorbant material melts glass in the portions of both glass sheets that are adjacent the absorbant material, and the melted glass from both sheets flows together to create the weld when the melted glass cools and hardens. The absorbant material can be dissolved and diffused into the melted glass to the extent that it no longer absorbs enough energy to keep the glass melted, thus, with appropriate proportioning of absorbant material to source energy power and welding heat needed, the process can be made self-stopping.

Claims

1. A method of welding together two juxtaposed sheets of glass that are transparent to certain radiation, comprising the steps of:

positioning a radiation absorbent and heat dissipating material between said sheets;

directing a beam of said radiation through at least one of said sheets to said material and allowing said material to absorb sufficient amounts of said radiation to produce and emanate sufficient heat to said glass sheets to melt portions of said glass sheets that are adjacent said material;

allowing the melted portions of said adjacent sheets to flow together and then to cool below melting point temperature and solidify to form a weld from the melted portion of said adjacent sheets.

2. The method of claim 1, including the step of dissolving said material into said melted glass.

3. The method of claim 2, including the step of allowing said dissolved material to diffuse into said melted glass to a sufficient extent that the material absorbs insufficient amounts of said radiation to produce enough heat to keep the glass melted.

4. The method of claim 1, wherein said material comprises an oxide.

5. The method of claim 4, wherein said oxide comprises iron oxide (FeO).

6. The method of claim 4, wherein said oxide comprises vanadium oxide (VO₂).

7. The method of claim 4, wherein said oxide comprises nickel oxide (NiO).

8. The method of claim 1, wherein said radiation has a wavelength in the range of 0.3 to 2.2 μ

m.

9. The method of claim 8, wherein said radiation is a laser beam.

10. The method of claim 9, wherein said laser beam is produced by a Nd:

YAG laser.

11. The method of claim 3, wherein the material is positioned with respect to the radiation and the glass sheets so as to produce sufficient heat to result in a completed weld fastening said two sheets together with a vacuum-tight seal.

12. A method of welding together and hermetically sealing a space between peripheral edges of two juxtaposed sheets of glass which are substantially transparent to optical energy, comprising the steps of:

positioning a strip of optical energy absorbent and heat dissipating material between the peripheral edges of the respective juxtaposed sheets of glass; and

irradiating said strip of material through at least one of said sheets of glass with enough of said optical energy to produce enough heat in said strip of material to heat, melt, and flow together portions of both of said sheets of glass that are adjacent said strip; and

allowing said melted portions of said sheets of glass to cool, solidify and to hermetically seal to each other.

13. The method of claim 12, including the step of dissolving said strip of material with the melted glass.

14. The method of claim 13, including the step of allowing the dissolved strip of material to diffuse into the melted glass enough to lower absorption of the optical energy enough so that insufficient heat is produced by the remaining absorption to keep the glass melted.