Opposed functional coatings having comparable single surface reflectances
A sheet-like pane bearing a low-maintenance coating on one surface and a low-emissivity coating on the opposite surface, wherein one of the low-maintenance coating and the low-emissivity coating has a single surface reflectivity of less than 3 times, and more than one-third, that of the other coating.
1. A sheet-like pane having generally opposed first and second major surfaces, the first major surface bearing a low-maintenance coating, the second major surface bearing a low-emissivity coating, wherein one of the low-maintenance coating and the low-emissivity coating has a single surface reflectance that is less than 3 times, and more than one-third, that of the other coating, wherein the low-emissivity coating includes an infrared-reflecting film comprising silver, and the low-maintenance coating includes a silicon-containing base film having a thickness of less than 100 angstroms and a titanium-containing film having a thickness of less than 50 angstroms.
2. The pane of claim 1 wherein one of the low-maintenance coating and the low-emissivity coating has a single surface reflectance that is less than about 2½ times, and more than about 0.4 times, that of the other coating.
3. The pane of claim 1 wherein the low-maintenance coating has a single surface reflectance that is between about 2 and about 2½ times that of the low-emissivity coating.
4. The pane of claim 1 wherein the titanium-containing film includes titanium dioxide or substoichiometric titanium dioxide.
5. The pane of claim 4 wherein the low-maintenance coating comprises at least two films and has a total thickness of less than 350 Å.
6. The pane of claim 5 wherein said total thickness is less than 175 Å.
7. The pane of claim 1 wherein the titanium-containing film has a thickness of between 5 angstroms and about 45 angstroms.
8. The pane of claim 1 wherein the titanium-containing film is provided as a mixed film comprising titania and silica.
9. The pane of claim 1 wherein the base film is deposited directly onto the first surface of the sheet-like pane and the titanium-containing film is deposited onto the base film.
10. The pane of claim 1 wherein the base film comprises silica and alumina.
11. The pane of claim 1 wherein the low-emissivity coating comprises, from the second major surface outwardly, an inner transparent dielectric film region having a thickness of between about 80 angstroms and about 100 angstroms, an infrared-reflecting film having a thickness of between about 60 angstroms and about 80 angstroms, a metal-containing blocker film having a thickness of between about 10 angstroms and between about 20 angstroms, a middle transparent dielectric film region having a thickness of between about 450 angstroms and about 570 angstroms, an infrared-reflecting film having a thickness of between about 115 angstroms and about 145 angstroms, a metal-containing blocker film having a thickness of between about 10 angstroms and about 20 angstroms, and an outer transparent dielectric film region having a thickness of between about 275 angstroms and about 345 angstroms.
12. The pane of claim 1 wherein both the low-maintenance coating and the low-emissivity coating are sputtered coatings.
13. The pane of claim 1 wherein the sheet-like pane is a window pane mounted in a window frame, such that the low-maintenance coating is exposed to an outdoor environment.
14. The pane of claim 1 wherein the pane is part of an insulating glass unit comprising two spaced-apart panes bounding a between-pane space.
15. The pane of claim 1 , wherein the low-maintenance coating has a single surface reflectance of less than 10%, and the low-emissivity coating has a single surface reflectance of less than 5%.
16. The pane of claim 1 , wherein the titanium-containing film has a refractive index between about 1.7 and about 1.57.
17. The pane of claim 1 , wherein the pane defines a thickness between about 1 millimeter and about 5 millimeters.
18. A sheet-like pane bearing a low-maintenance coating on a first major surface and a low-emissivity coating on a second major surface, wherein one of the low-maintenance coating and the low-emissivity coating has a single surface reflectance that is less than 3 times, and more than one-third, that of the other coating, wherein the low-maintenance coating has a thickness of less than about 350 angstroms and comprises a silicon-containing base film positioned directly over the first major surface and a titanium-containing film positioned directly over the base film, wherein the silicon-containing base film has a thickness of less than about 100 angstroms, and wherein the titanium-containing film has a thickness of less than about 50 angstroms, wherein the low-emissivity coating includes an infrared-reflecting film comprising silver.
19. A sheet-like pane bearing a low-maintenance coating on a first major surface and a low-emissivity coating on a second major surface, wherein one of the low-maintenance coating and the low-emissivity coating has a single surface reflectance that is between about 2 and about 2½ times that of the other coating, wherein the low-maintenance coating has a thickness of less than about 200 angstroms and comprises a base film positioned directly over the first major surface and a titanium-containing film positioned directly over the base film, wherein the base film comprises silica has a thickness of less than about 100 angstroms, and wherein the titanium-containing film has a thickness of less than about 50 angstroms, wherein the low-emissivity coating includes an infrared-reflecting film comprising silver.
20. The pane of claim 19 wherein the titanium-containing film is provided as a mixed film comprising titania and silica.
21. A method of depositing a low-emissivity coating onto a first major surface of a sheet-like pane and depositing a low-maintenance coating onto a second major surface of the pane, the method comprising:
depositing a low-maintenance coating onto the first major surface, wherein depositing the low-maintenance coating comprises depositing a silicon-containing base film to a thickness of less than about 100 angstroms directly on the first major surface, and depositing a titanium-containing film to a thickness of less than about 50 angstroms directly on the base film; and
depositing a low-emissivity coating onto the second major surface, wherein one of the low-emissivity coating and the low-maintenance coating has a single surface reflectance of less than 3 times, and more than one-third, that of the other coating.
22. The method of claim 21 wherein the base film comprises silica.
23. The method of claim 22 wherein the base film is deposited as a film consisting essentially of silica.
24. The method of claim 21 wherein the low-maintenance coating includes a titanium-containing film deposited as a film comprising titanium dioxide or substoichiometric titanium oxide.
25. The method of claim 24 wherein the titanium-containing film is deposited as a mixed film comprising titania and silica.
26. The method of claim 25 wherein the mixed film is deposited so that titania is present in an amount less than about 30 weight percent with the remainder being silica.
27. The method of claim 21 further comprising mounting the substrate in a window frame, such that the first major surface is exposed to an outdoor environment.
28. The method of claim 21 wherein the low-maintenance coating and low-emissivity coating are both deposited by sputtering.
29. The method of claim 28 wherein the sputtering is carried out while maintaining the pane at a temperature of less than about 250 degrees Celsius.