Coated substrate with high reflectance

• US 20050142365A1
• Filed: 11/02/2004
• Published: 06/30/2005
• Est. Priority Date: 03/20/1998
• Status: Active Grant

• Current Assignee: Eric Tixhon
• Original Assignee: Eric Tixhon
• Inventors: Tixhon, Eric
• Granted Patent: US 7,195,821 B2
• Time in Patent Office: Days
• US Class Current: 428/432
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• 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 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2217/75 Hydrophilic and oleophilic coatings
• CPC Class Codes: C03C 2218/112 by spraying
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/407 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A transparent coated substrate with rather high reflectance, especially for use as in exterior glazing panels for buildings or automotives, is provided by a substrate carrying a coating stack comprising a pyrolytically-formed main layer containing oxide of tin and an outer layer comprising TiO₂, whereby the so-coated substrate has a reflectance (RL) of more than 10%. The coated substrate advantageously shows photocatalytic and hydrophilic properties.

Claims

1. A transparent substrate carrying a coating stack comprising a pyrolytically-formed main layer comprising oxide of tin, wherein the stack includes an outer layer comprising titanium oxide-and having a refractive index in the range 2.0 to 2.8, whereby the so-coated substrate has a reflectance (RL) of more than 10%.

2. A coated transparent substrate as claimed in claim 1, in which the outer layer further contains an oxide of one or more of nickel, tin, zinc and zirconium

3b. b. A coated transparent substrate as claimed in claim 1, wherein the outer layer has photocatalytic properties, the photocatalytic activity being at least 2. 10⁻

3 cm−

1 min−

1, preferably greater than 5. 10<sup>−

3</sup> cm-1 min<sup>−

1</sup>.

3ter. ter. A coated transparent substrate as claimed in claim 1 or 3b, wherein the outer layer present, after UV irradiation, hydrophilic properties, the contact angle with water being lower than 10°

, preferably lower that 5°

.

4. A coated transparent substrate as claimed in claim 1 in which the outer layer comprises oxides of titanium and tin.

5b. b. A coated transparent substrate as claimed in claim 1, in which the main layer has a geometric thickness in the range of 40 to 500 nm.

5ter. ter. A coated transparent substrate as claimed in claim 5b, in which the main layer has a geometric thickness of at least 250 nm

6. A coated transparent substrate as claimed in claim 1, in which the outer layer has a geometric thickness in the range 10 to 350 nm.

7b. b. A coated transparent substrate as claimed in claim 1, in which the main layer contains oxides of tin and antimony.

8. A coated transparent substrate as claimed in claim 7b, in which the Sb/Sn molar ratio in the main coating layer is in the range 0.01 to 0.5.

9. A coated transparent substrate as claimed in claim 8, in which the Sb/Sn molar ratio is in the range 0.03 to 0.21.

12. A coated transparent substrate as claimed in claim 1, in which the coating stack further comprises an undercoat positioned between the substrate and the main coating layer.

13b. b. A coated transparent substrate as claimed in claim 12, wherein the undercoat is selected from oxide of silicon, aluminum oxinitride, and mixture of oxides of aluminum and of vanadium.

15. A coated transparent substrate as claimed in claims 12, in which the geometric thickness of-the undercoat is in the range 30 to 100 nm. preferably 60 to 75 nm.

16. A coated transparent substrate as claimed in claims 12, in which the undercoat imparts to the coated substrate a more neutral tint in reflection.

16b. b. A coated transparent substrate as claimed in claim 16, wherein the Hunter values in reflection a and b are comprised between −

15 and 5, and preferably between −

10 and 0.

17. A coated transparent substrate as claimed in claim 1, in which the coating stack further comprises an intermediate layer positioned between the main coating layer and the outer layer.

18. A coated transparent substrate as claimed in claim 17, in which the intermediate layer comprises aluminum oxide or silicon oxide or SnO₂ doped with fluorine.

19. A coated transparent substrate as claimed claim 1, having a luminous transmittance (TL) of at least 40%, preferably at least 60% and more preferably at least 65%.

21. A coated transparent substrate as claimed in claim 1, having a maximum reflectance (RL) of 30% and preferably of 25%.

22. A coated transparent substrate as claimed in claim 21, having a maximum reflectance (RL) of 20%.

23. A glazing panel comprising a coated transparent substrate as claimed in any preceding claim.

24. A glazing panel as claimed in claim 23, comprising two or more substrate sheets of which one is a coated transparent substrate as claimed in any of claims 1 to 22.

25. A glazing panel as claimed in claim 23 or claim 24, for use as a building glazing panel.

26. A glazing panel as claimed in claim 23 or claim 24, for use as a vehicle window.