Abstract A method of producing a heat-reflecting glass sheet which comprises applying to a glass sheet by vacuum deposition a zinc sulphide anti-reflection layer followed by a metal layer, of for example gold, silver or copper, with a high infrared reflection capacity. In accordance with the invention, the colour-imparting interference action of the zinc sulphide layer is stabilized to provide colour uniformity, even if large glass surfaces are involved, by first applying to the glass sheet a vacuum-coated dielectric intermediate layer which is substantially absorptionfree for visible light and has a refractive index corresponding to that of the glass sheet. Preferred materials for the said intermediate layer are a metal oxide or metal oxide mixture, silicon oxides such as silicon monoxide and glass. The thickness of the intermediate layer is suitably substantially less than the wavelength of visible light.
A HEAT-REFLECTING GLASS SHEET, COMPRISING: A GLASS SHEET, A ZINC SULPHIDE ANTI-REFLECTION LAYER WHICH IS VACUUM-COATED ONTO THE GLASS SHEET IN A THICKNESS OF 200 TO 600 A, AND A METAL LAYER OF HIGH INFRARED REFLECTION CAPACITY WHICH IS VACUUM-COATED ONTO THE ANTI-REFLECTION LAYER AND HAVING A THICKNESS OF 150 TO 500 A, WHEREIN THE IMPROVEMENT COMPRISES, A DIELECTRIC INTERMEDIATE LAYER WHICH IS SUBSTANTIALLY ABSORPTION-FREE FOR VISIBLE LIGHT AND CONSISTS ESSENTIALLY OF A MEMBER OF THE GROUP CONSISTING OF SILICON MONOXIDE AND SILICON DIOXIDE WITH A REFRACTION INDEX CORRESPONDING SUBSTANTIALLY TO THAT OF THE GLASS SHEET, THE SAID INTERMEDIATE LAYER BEING VACUUM-COATED BETWEEN THE GLASS SHEET AND THE ZINC SULPHIDE ANTI-REFLECTION LAYER AND HAVING A THICKNESS OF 30 TO 100 A.
Claim 2
Dependent Claim
121 words
A HEAT-REFLECTING GLASS SHEET, COMPRISING: A GLASS SHEET, A ZINC SULPHIDE ANTI-REFLECTION LAYER WHICH IS VACUUM-COATED ONTO THE GLASS SHEET IN A THICKNESS OF 200 TO 600 A, AND A METAL LAYER OF HIGH INFRARED REFLECTION CAPACITY WHICH IS VACUUM-COATED ONTO THE ANTI-REFLECTION LAYER AND HAVING A THICKNESS OF 150 TO 500 A, WHEREIN THE IMPROVEMENT COMPRISES, A DIELECTRIC INTERMEDIATE LAYER WHICH IS SUBSTANTIALLY ABSORPTION-FREE FOR VISIBLE LIGHT AND CONSISTS ESSENTIALLY OF A MEMBER OF THE GROUP CONSISTING OF SILICON MONOXIDE AND SILICON DIOXIDE WITH A REFRACTION INDEX CORRESPONDING SUBSTANTIALLY TO THAT OF THE GLASS SHEET, THE SAID INTERMEDIATE LAYER BEING VACUUM-COATED BETWEEN THE GLASS SHEET AND THE ZINC SULPHIDE ANTI-REFLECTION LAYER AND HAVING A THICKNESS OF 30 TO 100 A.
Claim 3
Dependent Claim
15 words
The heat-reflecting glass sheet as claimed in claim 1, wherein the metal layer comprises gold.
Claim 4
Dependent Claim
42 words
The heat-reflecting glass sheet according to claim 1, wherein at least one further protective layer is disposed on that surface of the metal layer which faces away from the zinc sulphide anti-reflection layer, said further protective layer consisting essentially of zinc sulphide.
Claim 5
Dependent Claim
29 words
The heat-reflecting glass sheet according to claim 3 and including a protective layer deposited on said further protective layer of zinc sulphide and consisting essentially of a silicon oxide.