REFLECTIVE ARTICLE HAVING MULTIPLE REFLECTIVE COATINGS

• US 20090233037A1
• Filed: 12/09/2008
• Published: 09/17/2009
• Est. Priority Date: 03/11/2008
• Status: Active Grant

• Current Assignee: Vitro Flat Glass LLC (Compagnie De Saint-Gobain)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Medwick, Paul A., Wagner, Andrew V., Marietti, Gary J.
• Granted Patent: US 8,445,098 B2
• Time in Patent Office: Days
• US Class Current: 428/68
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3639 Multilayers containing at least two functional metal layers
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3652 the coating stack containing at least one sacrificial layer to protect the metal from oxidation
• CPC Class Codes: C03C 17/3663 specially adapted for use as mirrors
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: F24S 23/82 characterised by the material or the construction of the reflector
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/0858 the reflecting layers comprising a single metallic layer with one or more dielectric layers
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y10T 428/23 Sheet including cover or casing
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

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.

Claims

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;

a primary reflective coating formed over at least a portion of the secondary reflective coating and comprising at least one metallic layer; and

a protective coating formed over at least a portion of the primary reflective coating.

2. The reflective article of claim 1, wherein the secondary reflective coating comprises a first layer comprising a material selected from metal oxides, nitrides, and oxynitrides and a second layer formed over at least a portion of the first layer and comprising a material selected from metal oxides, nitrides, and oxynitrides.

3. The reflective article of claim 2, wherein the first layer comprises at least one material selected from titania, zirconia, zinc stannate, silicon nitride, zinc oxide, tin doped zinc oxide, niobium oxide, tantalum oxide, and alloys, mixtures and combinations thereof, and the second layer comprises at least one material selected from silica, alumina, a fluoride, and alloys, mixtures and combinations thereof.

4. The reflective article of claim 3, wherein the first layer has a higher refractive index than the second layer.

5. The reflective article of claim 4, wherein the first layer comprises titania having a thickness in the range of 10 nm to 40 nm and the second layer comprises silica having a thickness in the range of 20 nm to 60 nm.

6. 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.

7. The reflective article of claim 6, wherein the primary reflective coating comprises silver having a thickness in the range of 50 nm to 400 nm.

8. The reflective article of claim 1, including an adhesion layer positioned between the secondary reflective coating and primary reflective coating.

9. The reflective article of claim 8, wherein the adhesion layer comprises at least one material selected from oxides, nitrides, or oxynitrides of zinc, tin, titanium, or combinations thereof.

10. The reflective article of claim 9, wherein the adhesion layer has a thickness less than or equal to 5 nm.

11. The reflective article of claim 1, wherein the protective coating comprises a material selected from silica, alumina, or a mixture of silica and alumina and has a thickness in the range of 75 nm to 120 nm.

12. The reflective article of claim 1, including an encapsulation structure formed over at least a portion of the protective coating.

13. The reflective article of claim 10, wherein the encapsulation structure comprises a polymeric material.

14. The reflective article of claim 13, wherein the encapsulation structure further comprises a glass substrate adhered to the polymeric layer.

15. The reflective article of claim 1, including a top coat formed between the primary reflective coating and the protective coating, the top coat comprising at least one dielectric layer.

16. The reflective article of claim 15, wherein the top coat comprises at least one of zinc oxide, tin oxide, or zinc stannate.

17. The reflective article of claim 15, wherein the top coat comprises:

a first zinc oxide layer;

a zinc stannate layer over at least a portion of the first zinc oxide layer; and

a second zinc oxide layer over at least a portion of the zinc stannate layer.

18. The reflective article of claim 1, including an anti-corrosion coating positioned between the primary reflective coating and the protective coating.

19. The reflective article of claim 18, 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.

20. The reflective article of claim 1, further comprising a photoactive coating formed over at least a portion of the first major surface.

21. 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 a material selected from metal oxides, nitrides, and oxynitrides and a second layer formed over at least a portion of the first layer and comprising a material selected from metal oxides, nitrides, and oxynitrides, 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 at least one layer comprising a material selected from metal oxides, nitrides, oxynitrides, borides, fluorides, or carbides, and wherein the top coat 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 comprises a material selected from silica, alumina, or a mixture of silica and alumina and has a thickness in the range of 50 nm to 500 nm.

22. A method of making a reflective article, comprising:

providing a transparent glass substrate having a first major surface and a second major surface;

forming a secondary reflective coating over at least a portion of the second major surface and comprising one or more dielectric layers;

forming a primary reflective coating over at least a portion of the secondary reflective coating and comprising at least one metallic layer; and

forming a protective coating over at least a portion of the primary reflective coating.

23. The method of claim 22, including heating the coated substrate to a temperature sufficient to bend or heat treat the glass.