Low emissivity coatings on transparent substrates

• US 4,462,883 A
• Filed: 09/19/1983
• Issued: 07/31/1984
• Est. Priority Date: 09/21/1982
• Status: Expired due to Term

• Current Assignee: Pilkington Brothers Unlimited (Pilkington PLC)
• Original Assignee: Pilkington Brothers Unlimited (Pilkington PLC)
• Inventors: Hart, Frederick H.
• Primary Examiner(s): Demers, Arthur P.
• Application Number:
  US06/533,796
• Time in Patent Office: 316 Days
• Field of Search: 428/621, 204/192 C, 204/192 R, 204/192 P
• US Class Current: 204/192.26
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3615 Coatings of the type glass/metal/other inorganic layers, at least one layer being non-metallic
• 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: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/18 on other inorganic substrates
• CPC Class Codes: C23C 14/20 on organic substrates
• CPC Class Codes: G02B 1/116 including electrically conducting layers
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: Y10T 428/12535 with additional, spatially distinct nonmetal component

Abstract

A low emissivity coating on a transparent substrate of glass or plastics material is produced by cathode sputtering a layer of silver and thereafter reactively sputtering an anti-reflection metal oxide layer over the silver in the presence of oxygen or an oxidizing gas, wherein a small amount of an additional metal other than silver is sputtered onto the silver before the overlying anti-reflection metal oxide layer is applied.

The process produces a new low emissivity coated product comprising a glass or plastics substrate with a low emissivity coating comprising a silver layer, a small amount of additional metal dispersed non-uniformly in the silver layer and possibly extending over the silver layer, and an overlying anti-reflection metal oxide coating.

Claims

1. A process for the production of a low emissivity coating on a transparent substrate of glass or plastics material by cathode sputtering comprising, in sequence,

(i) sputtering a layer of silver from 5 to 30 nm thick onto the transparent glass or plastics substrate

(ii) sputtering at least one additional metal other than silver in amount equivalent to a layer 0.5 to 10 nm thick onto the silver and

(iii) reactively sputtering, in the presence of oxygen or an oxidising gas, at least one anti-reflection metal oxide layer over the silver and additional metal.

2. A process according to claim 1 wherein the or each additional metal is a metal which forms a colourless metal oxide on subsequent reactive sputtering of the anti-reflection metal oxide.

3. A process according to claim 1 wherein the additional metal is copper.

4. A process according to claim 1 wherein additional metal is sputtered onto the silver in a total amount equivalent to a layer 1 to 5 nm thick.

5. A process according to claim 1 wherein the layer of silver sputtered is 8 to 15 nm thick.

6. A process according to claim 1 wherein an anti-reflection layer is sputtered onto the substrate before sputtering of the silver layer.

7. A process according to claim 1 for the production of a low emissivity coating on a transparent substrate of glass by cathode sputtering comprising

(a) depositing an anti-reflection layer of SnO₂ 30 to 50 nm thick onto the glass substrate by reactive sputtering of tin in the presence of oxygen or an oxidising gas;

(b) sputtering a layer of silver 8 to 12 nm thick onto said anti-reflection layer;

(c) sputtering copper in an amount equivalent to a layer of copper 1 to 5 nm thick onto said silver layer;

and thereafter

(d) depositing on the coating so formed an anti-reflection layer of SnO₂ 30 to 50 nm thick by reactive sputtering of tin in the presence of oxygen or an oxidising gas.

8. A process according to claim 1 wherein the sputtering processes are aided by magnetic enhancement.

9. A process according to claim 1 for the production of a low emissivity coating on a transparent glass substrate by D.C. magnetron sputtering comprising, in sequence,

(i) sputtering an anti-reflection metal oxide layer on to the substrate;

(ii) sputtering a layer of silver from 8 to 15 nm thick onto the said layer;

(iii) sputtering an additional metal or metals other than silver in an amount equivalent to a layer 0.5 to 5 nm thick onto the silver; and

(iv) reactively sputtering, in the presence of oxygen or an oxidising gas, an anti-reflection metal oxide layer or layers over the silver and additional metal.

10. A process according to claim 9 wherein the additional metal is copper.

11. A process according to claim 9 wherein the additional metal is a metal which forms a colourless metal oxide on subsequent reactive sputtering of the anti-reflection metal oxide layer.