Transparent substrate with an antireflection, low-emissivity or solar-protection coating
A transparent substrate and methods of making a transparent substrate having, on at least one of its faces, an antireflection coating made of a multilayer stack of alternating thin layers of high and low refractive indices. Preferably, the thin layers are based on a dielectric material. At least one of the thin high-index layers comprises titanium oxide which is modified so as to reduce its refractive index to a value of at most 2.40, preferably to a value of at most 2.35.
1. A transparent substrate having at least one surface comprising, an antireflection coating comprising a multilayer stack having alternating layers of high and low refractive indices, comprising:
(a) at least one high-index multilayer having a refractive index value higher than 1.9 and lower than 2.45, comprising a trilayer with alternatively one titanium oxide layer, one tin oxide layer and one titanium oxide layer; and
(b) at least one low-index layer having a refractive index of from 1.30 to 1.65,
wherein the high-index multilaver is positioned further from the transparent substrate relative to a layer having a refractive index lower than the titanium oxide layer.
2. The transparent substrate of claim 1 , wherein said high-index multilayer has a refractive index ranging from 2.25 to 2.38.
3. The transparent substrate of claim 1 , wherein said multilayer stack comprises a dielectric material, a low emissivity material, or a solar-protection coating.
4. The transparent substrate of claim 1 , wherein said at least one low-index layers comprises one or more of silicon oxide, aluminum oxide, aluminum oxyfluoride, aluminum fluoride, magnesium fluoride, or mixtures thereof.
5. The transparent substrate of claim 4 , wherein said at least one low-index layers comprise at least one of halogenated silicon oxide or halogenated aluminum oxide.
6. The transparent substrate of claim 4 , wherein the layer of said antireflection coating most removed from said substrate is a low-index layer comprising a SiO2-Al 2 O3, wherein the atomic percent of aluminum with respect to silicon is from 5 to 20 percent.
7. The transparent substrate of claim 1 , which further comprises a high index layer distinct from the high-index multilayer, having a refractive index of between 1.9 and 2.2 and which comprises tantalum oxide, zirconium oxide, tin oxide, indium oxide, zinc oxide, niobium oxide, silicon nitride, or aluminum nitride.
8. A glazing comprising the transparent substrate of claim 1 .
9. The glazing of claim 8 , further comprising a layer or multilayer stack that is a solar protection layer, a heat absorbing layer, a UV protecting layer, an antistatic layer, a low emissivity layer, a heated layer, an anti-fouling layer, a hydrophobic organic layer having an anti-rain function, a hydrophilic organic layer having an anti-fogging function, or a silvering layer.
10. The glazing of claim 8 , wherein the glazing comprises extra-clear glass or solid-tinted glass.
11. The glazing of claim 8 , wherein the glazing comprises a transparent polymer material.
12. The glazing of claim 11 , wherein the transparent polymer material comprises a polycarbonate or a polyacrylate.
13. The glazing of claim 8 , comprised in internal or external glazing for buildings, a motor-vehicle window, a mirror, a display screen, a decorative glass, a shop window, a shop-counter, or a refrigerated display-cabinet.
14. A motor vehicle window comprising the glazing of claim 8 .
15. A mirror comprising the glazing of claim 8 .
16. A display screen comprising the glazing of claim 8 .
17. A shop window comprising the glazing of claim 8 .
18. A glass comprising the glazing of claim 8 .
19. The glazing of claim 10 , wherein the glazing is toughened, reinforced, curved, or bent.