Reflective article having multiple reflective coatings
View Patent ↗A reflective article, such as a solar mirror, includes a highly transparent substrate having a first major surface and a second major surface. At least one reflective coating is formed over at least a portion of one of the surfaces, e.g., the second major surface (or, alternatively, the first major surface). The reflective coating includes at least one metallic layer. An encapsulation structure can be formed over at least a portion of the second reflective coating.
1. A reflective article, comprising:
a transparent substrate having a first major surface and a second major surface;
a secondary reflective coating formed over at least a portion of the second major surface and comprising one or more dielectric layers, wherein the secondary reflective coating comprises a first layer comprising titania having a thickness in the range of 10 nm to 20 nm, and a second layer comprising silica having a thickness in the range of 20 nm to 60 nm;
a primary reflective coating formed over at least a portion of the secondary reflective coating and comprising at least one metallic layer;
a protective coating formed over at least a portion of the primary reflective coating; and
a top coat formed between the primary reflective coating and the protective coating, said top coat comprising zinc stannate having a thickness in the range of 100 nm to 200 nm,
wherein the protective coating consists essentially of a material selected from the group consisting of silica, alumina, or a mixture of silica and alumina.
2. The reflective article of claim 1 , wherein for the secondary reflective coating, the first layer has a higher refractive index than the second layer.
3. The reflective article of claim 1 , wherein the protective coating has a thickness in the range of 75 nm to 120 nm.
4. The reflective article of claim 1 , including an encapsulation structure formed over at least a portion of the protective coating.
5. The reflective article of claim 1 , further comprising a photoactive coating formed over at least a portion of the first major surface.
6. The reflective article of claim 1 , wherein said material of said protective coating is selected from the group consisting of silica, or said mixture of silica and alumina.
7. The reflective article of claim 1 , wherein the primary reflective coating is opaque to visible light and comprises at least one metal selected from platinum, iridium, osmium, palladium, aluminum, gold, copper, silver, or mixtures, alloys, or combinations thereof.
8. The reflective article of claim 7 , wherein the primary reflective coating comprises silver having a thickness in the range of 50 nm to 400 nm.
9. The reflective article of claim 1 , including an adhesion layer positioned between the secondary reflective coating and primary reflective coating.
10. The reflective article of claim 9 , wherein the adhesion layer comprises at least one material selected from oxides, nitrides, or oxynitrides of zinc, tin, titanium, or combinations thereof.
11. The reflective article of claim 10 , wherein the adhesion layer has a thickness less than or equal to 5 nm.
12. The reflective article of claim 4 , wherein the encapsulation structure comprises a polymeric material.
13. The reflective article of claim 12 , wherein the encapsulation structure further comprises a glass substrate adhered to the polymeric layer.
14. The reflective article of claim 1 , including an anti-corrosion coating positioned between the primary reflective coating and the protective coating.
15. The reflective article of claim 14 , wherein the anti-corrosion coating comprises at least one metal or metal alloy from members of Groups 2-16 of the Periodic Table of the Elements.
16. A reflective article, comprising:
a transparent glass substrate having a first major surface and a second major surface;
a secondary reflective coating formed over at least a portion of the second major surface, wherein the secondary reflective coating comprises a first layer comprising titania having a thickness in the range of 10 nm to 40 nm, and a second layer formed over at least a portion of the first layer and comprising silica having a thickness in the range of 20 nm to 60 nm, and wherein the first layer has a higher refractive index than the second layer;
a primary reflective coating formed over at least a portion of the secondary reflective coating, wherein the primary reflective coating comprises at least one metal selected from platinum, iridium, osmium, palladium, aluminum, gold, copper, silver, or mixtures, alloys, or combinations thereof, and wherein the primary reflective coating has a thickness in the range of 50 nm to 500 nm, and wherein the primary reflective coating is opaque to visible light;
an anti-corrosion coating formed over at least a portion of the primary reflective coating, wherein the anti-corrosion coating comprises at least one metal or metal alloy from members of Groups 2-16 of the Periodic Table of the Elements and has a thickness in the range of 20 nm to 40 nm;
a top coat formed over at least a portion of the anti-corrosion coating, wherein the top coat comprises zinc stannate, and wherein the top coat is dielectric and has a thickness in the range of 5 nm to 500 nm; and
an inorganic protective coating formed over at least a portion of the top coat, wherein the protective coating consists essentially of a material selected from the group consisting of silica, alumina, or a mixture of silica and alumina, and has a thickness in the range of 50 nm to 500 nm.
17. The reflective article of claim 16 , wherein said anti-corrosion coating comprises a nickel-containing alloy.