Heat-treatment convertible coated glass and method of converting same

• US 5,376,455 A
• Filed: 10/05/1993
• Issued: 12/27/1994
• Est. Priority Date: 10/05/1993
• Status: Expired due to Term

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lingle, Philip J., Hartig, Klaus W.
• Primary Examiner(s): Robinson, Ellis P.
• Assistant Examiner(s): Speer, Timothy M.
• Application Number:
  US08/131,696
• Time in Patent Office: 448 Days
• Field of Search: 428/428, 428/432, 428/334, 428/335, 428/336, 428/448, 428/689, 428/698, 428/699, 428/450, 428/472, 428/622, 428/627, 428/630, 428/631, 428/673, 428/680
• US Class Current: 428/428
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3607 Coatings of the type glass/inorganic compound/metal
• CPC Class Codes: C03C 17/3626 one layer at least containing a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3652 the coating stack containing at least one sacrificial layer to protect the metal from oxidation
• CPC Class Codes: C03C 17/366 Low-emissivity or solar control coatings
• CPC Class Codes: C03C 17/3681 the multilayer coating being used in glazing, e.g. windows or windscreens
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: Y10T 428/12542 More than one such component
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/12597 Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
• CPC Class Codes: Y10T 428/12896 Ag-base component
• CPC Class Codes: Y10T 428/12944 Ni-base component
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A high performance, durable sputter coated, heat-treatable glass which after heat-treatment exhibits about 76% or more visible transmittance, a hemispherical emissivity (E_h) of about 0.16 or less, and a normal emissivity (E_n) of about 0.12 or less is formed by sputter coating a layer system on a glass substrate which includes an undercoat and overcoat of Si₃ N₄, a silver layer, and two nickel or nichrome layers on opposite sides of the silver layer, and wherein the lower nickel-based layer is about three times as thick as the other nickel based layer. The increased thickness of the lower nickel-based layer allows the coated glass article to be both heat-treatable, and "low-E" after the heat-treatment. This allows matching with other known glasses in the family of layer components by way of the heat-treatment process. The layer system employed allows, even if not matchable to another glass, for the sputter coating operation to include the coating of other members of the family of coating without change of targets, efficient use of the coater targets that exist, and minimal operational changes during production.

Claims

1. A heat-treatable coated glass article having a sputter coated layer system thereon which comprises from the glass outwardly:

a) a first layer of Si₃ N₄ having a thickness of about 350 Å

-450 Å

;

b) a first layer of nickel or nichrome having a thickness of greater than about 20Å

;

c) a layer of silver having a thickness of about 50 Å

-120 Å

;

d) a second layer of nickel or nichrome having a thickness of at least about 7 Å

;

e) a second layer of Si₃ N₄ having a thickness of about 450 Å

-550 Å

; and

wherein

said coated glass article when said glass is clear glass and has a thickness of about 2.5 mm-3.5 mm, has the following characteristics after heat-treatment;

space="preserve" listing-type="tabular">______________________________________ Transmittance (Ill. C 10°

obs.) about 76%-78% Sheet resistance (R.sub.s) less than about 12 ohms/sq. Emissivity, normal (E.sub.n) less than about 0.12 Emissivity, hemispherical (E.sub.h) less than about 0.16. ______________________________________

2. The glass article according to claim 1, wherein the thickness of the first Si₃ N₄ layer is about 375 Å

and the thickness of the second Si₃ N₄ layer is about 500 Å

.

3. The glass article according to claim 2 wherein the silver layer is about 75 Å

thick.

4. The glass article according to claim 1, wherein the thickness of the first sputter coated nickel or nichrome layer is about three times as great as the thickness of the second nickel or nichrome layer.

5. The glass article according to claim 4, wherein the first nickel or nichrome layer is about 20-50 Å

thick and the second nickel or nichrome layer is about 7-15 Å

thick.

6. The glass article according to claim 1 wherein said layer system consists essentially of said five layers, and wherein said sputter coated article is durable and chemically resistant.

7. A sputter-coated, heat treated glass article wherein, prior to heat treatment, said article is provided with a pre-coated layer system which from the glass outwardly comprises:

a) a first layer of Si₃ N₄ having a thickness of about 350 Å

-450 Å

;

b) a first layer of nickel or nichrome having a thickness of greater than about 20 Å

;

c) a layer of silver having a thickness of about 50 Å

-120 Å

;

d) a second layer of nickel or nichrome having a thickness of at least about 7 Å

;

e) a second layer of Si₃ N₄ having a thickness of about 450 Å

-550 Å

; and

wherein

said sputter-coated, heat treated glass article, when said glass is clear glass and has a thickness of about 2.5 mm-3.5 mm, has the following characteristics;

space="preserve" listing-type="tabular">______________________________________ Transmittance (Ill. C 10°

obs.) about 76%-78% Sheet resistance (R.sub.s) less than about 12 ohms/sq. Emissivity, normal (E.sub.n) less than about 0.12 Emissivity, hemispherical (E.sub.h) less than about 0.16. ______________________________________

8. A sputter-coated, heat treated glass article according to claim 7 wherein said heat treatment is selected from bending, tempering, heat strengthening, or combinations thereof.

9. A sputter-coated, heat treated glass article according to claim 8 wherein said heat treatment includes tempering.

10. A sputter-coated, heat treated glass article according to claim 7 wherein said emissivity of said heat treated glass article is less than the emissivity of said pre-coated, unheat treated glass article.

11. The heat treated article according to claim 10, wherein said normal emissivity (E_n) is about 0.15 or less before heat-treatment and about 0.11 or less after heat-treatment;

and wherein said hemispherical emissivity (E_h) is less than about 0.18 before heat-treatment and less than about 0.14 after heat-treatment.