Low-maintenance coatings

• US 20060057298A1
• Filed: 07/12/2005
• Published: 03/16/2006
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Original Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Inventors: Krisko, Annette J., Pfaff, Gary L., Brownlee, James, Myli, Kari
• Granted Patent: US 7,713,632 B2
• Time in Patent Office: Days
• US Class Current: 427/402
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3423 at least one of the coatings comprising a suboxide
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/155 by reactive sputtering
• CPC Class Codes: C03C 2218/156 by magnetron sputtering
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence

Abstract

The invention provides a substrate bearing a low-maintenance coating. The coating includes two films: a first film comprising silica (e.g., silicon dioxide) and a second film comprising titania (e.g., titanium dioxide). Preferably, both films are provided within particular thickness ranges. The invention also provides methods of depositing such coatings.

Claims

1. A low-maintenance coating on a glass sheet, the coating comprising a first film positioned directly over a first major surface of the glass sheet and a second film positioned directly over the first film, wherein the first film includes a base film and has a thickness of less than about 300 angstroms, and wherein the second film includes a photocatalytic film and has a thickness of less than about 300 angstroms.

2. The low-maintenance coating of claim 1 wherein the base film is silica.

3. The low-maintenance coating of claim 1 wherein the photocatalytic film is titania.

4. The low-maintenance coating of claim 1 wherein the thickness of the first film is between about 70 angstroms and about 120 angstroms.

5. The low-maintenance coating of claim 1 wherein the thickness of the second film is between about 30 angstroms and about 120 angstroms.

6. The low-maintenance coating of claim 1 wherein the glass sheet is a window pane mounted in a window frame, and wherein the coated first major surface is exposed to an outdoor environment.

7. The low-maintenance coating of claim 2 wherein the coated first major surface is in periodic contact with rain.

8. The low-maintenance coating of claim 1 wherein the first film consists essentially of silica and the second film consists essentially of titania.

9. The low-maintenance coating of claim 8 wherein the silica is silicon dioxide, and the titania is titanium dioxide or substoichiometric titanium oxide.

10. The low-maintenance coating of claim 1 wherein the first and second films are both sputtered films.

11. A method of depositing a low-maintenance coating, the method comprising depositing a low-maintenance coating on a glass sheet, wherein a first film is deposited directly over a first major surface of the glass sheet and a second film is deposited directly over the first film, wherein the first film comprises a base film and is deposited at a thickness of less than about 300 angstroms, and wherein the second film comprises a photocatalytic film and is deposited at a thickness of less than about 300 angstroms.

12. The method of depositing a low-maintenance coating of claim 11 wherein the base film is silica.

13. The method of depositing a low-maintenance coating of claim 11 wherein the photocatalytic film is titania.

14. The method of depositing a low-maintenance coating of claim 11 wherein the thickness at which the first film is deposited is between about 70 angstroms and about 120 angstroms.

15. The method of depositing a low-maintenance coating of claim 11 wherein the thickness at which the second film is deposited is between about 30 angstroms and about 120 angstroms.

16. The method of claim 11 further comprising mounting the glass sheet in a window frame, such that the coated first major surface is exposed to an outdoor environment and is in periodic contact with rain.

17. The method of claim 11 wherein the first film is deposited as film consisting essentially of silica and the second film is deposited as film consisting essentially of titania.

18. The method of claim 17 wherein the silica is deposited as silicon dioxide, and the titania is deposited as titanium dioxide or substoichiometric titanium oxide.

19. The method of claim 11 wherein the first and second films are both deposited by sputtering.

20. The method of claim 19 wherein the sputtering is carried out while maintaining the glass sheet at a temperature of less than 200 degrees Celsius.

21. A low-maintenance coating on a glass sheet, the coating comprising a first film positioned directly over a first major surface of the glass sheet and a second film positioned directly over the first film, wherein the first film consists essentially of silica and has a thickness of between about 30 angstroms and about 300 angstroms, and wherein the second film consists essentially of titania and has a thickness of less than 100 angstroms but greater than about 30 angstroms.

22. The low-maintenance coating of claim 21 wherein the first film has a thickness of less than about 100 angstroms.

23. The low-maintenance coating of claim 21 wherein the second film has a thickness of less than about 80 angstroms.

24. The low-maintenance coating of claim 23 wherein the first film has a thickness of less than about 100 angstroms.