First surface mirror with sol-gel applied protective coating for use in solar collector or the like

• US 20070178316A1
• Filed: 01/30/2006
• Published: 08/02/2007
• Est. Priority Date: 01/30/2006
• Status: Abandoned Application

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Mellott, Nathan
• Application Number:
  US11/341,869
• Publication Number:
  US 20070178316A1
• Time in Patent Office: Days
• US Class Current: 428/426
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3626 one layer at least containing a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3649 made of metals other than silver
• CPC Class Codes: C03C 17/3663 specially adapted for use as mirrors
• CPC Class Codes: C03C 17/3678 specially adapted for use in solar cells
• CPC Class Codes: C03C 2217/72 Decorative coatings
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: F24S 23/82 characterised by the material or the construction of the reflector
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/0833 comprising inorganic materials only
• CPC Class Codes: G02B 5/085 at least one of the reflecting layers comprising metal
• CPC Class Codes: G02B 5/0875 the reflecting layers comprising two or more metallic layers
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers

Abstract

A first-surface mirror includes protective coating and is for use in a solar collector or the like. In certain example embodiments, a sol-gel coating is applied, in a wet form, over a reflective coating of a first surface mirror. The sol-gel coating is then heated following its application, to drive off liquid(s) of the sol-gel so that the coating densifies and forms a solid protective coating over the reflective coating. In certain example embodiments, the protective coating may be of or include silica or the like so as to protect the reflective coating and improve durability.

Claims

1. A method of making a first surface mirror, the method comprising:

forming a reflective coating on a glass substrate;

forming a sol-gel on the glass substrate over the reflective coating, the sol-gel including a Si-inclusive precursor and one or more of water, alcohol, acid, base, and/or a hydroalcoholic mixture; and

heat treating the sol-gel at from about 200 to 1,000 degrees C. for densifying and forming a glassy silica based protective coating over the reflective coating of the first surface mirror.

2. The method of claim 1, wherein the protective coating comprises at least about 75% SiO₂.

3. The method of claim 1, wherein the protective coating comprises at least about 80% SiO₂.

4. The method of claim 1, wherein the protective coating comprises at least about 85% SiO₂.

5. The method of claim 1, wherein the protective coating has an index of refraction (n) of from about 1.4 to 1.55.

6. The method of claim 1, wherein the sol-gel is formed on the substrate at approximately room temperature.

7. The method of claim 1, wherein the reflective coating comprises at least one reflective layer comprises Al or Ag.

8. The method of claim 1, wherein the reflective coating is a multi-layer coating comprising at least one reflective layer and first and second dielectric layers, wherein the reflective layer is located between the glass substrate and the first and second dielectric layers.

9. The method of claim 1, wherein the Si-inclusive precursor comprises a silane.

10. The method of claim 1, wherein the Si-inclusive precursor comprises TEOS and/or TMOS.

11. The method of claim 1, wherein the protective coating is the outermost layer of the mirror.

12. A solar collector comprising the first-surface mirror of claim 1.

13. A method of making a first surface mirror, the method comprising:

forming a reflective coating on a glass substrate;

forming a sol-gel on the glass substrate over the reflective coating, the sol-gel including a precursor and one or more of water, alcohol, acid and/or base, and/or a hydroalcoholic mixture; and

heat treating the sol-gel so as to form a solid silica based protective coating over the reflective coating of the first surface mirror.

14. The method of claim 13, wherein the protective coating comprises at least about 75% SiO₂.

15. The method of claim 13, wherein the protective coating comprises at least about 80% SiO₂.

16. A solar collector comprising the first-surface mirror of claim 13.

17. A first surface mirror, comprising:

a reflective coating supported by a glass substrate; and

a glassy silica based protective coating provided on the glass substrate over the reflective coating of the first surface mirror.

18. A solar collector comprising the first-surface mirror of claim 17.