Electrochromic device having a self-cleaning hydrophilic coating with an acid resistant under layer

• US 20050094279A1
• Filed: 10/29/2004
• Published: 05/05/2005
• Est. Priority Date: 10/30/2003
• Status: Abandoned Application

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Tonar, William L., Anderson, John S., Forgette, Jeffrey A., Kar, Kevin B.
• Application Number:
  US10/976,940
• Publication Number:
  US 20050094279A1
• Time in Patent Office: Days
• US Class Current: 359/604
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2217/75 Hydrophilic and oleophilic coatings
• CPC Class Codes: C03C 2217/948 Layers comprising indium tin oxide [ITO]
• CPC Class Codes: C03C 2218/365 Coating different sides of a glass substrate
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence
• CPC Class Codes: G02B 27/0006 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation G02B1/18 takes precedence; cleaning in general B08B
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 2201/50 Protective arrangements

Abstract

A variable reflectance rearview mirror for a vehicle, comprising: (a) a variable reflectance mirror element having a reflectivity that varies in response to an applied potential so as to exhibit at least a high reflectance state and a low reflectance state; (b) a self-cleaning, hydrophilic coating applied to a front surface of said mirror element; and (c) an acid resistant layer applied to a surface of the self-cleaning hydrophilic coating.

Claims

1. A variable reflectance rearview mirror for a vehicle, comprising:

a variable reflectance mirror element having a reflectivity that varies in response to an applied potential so as to exhibit at least a high reflectance state and a low reflectance state;

a self-cleaning, hydrophilic coating applied to a front surface of the mirror element; and

an acid resistant layer applied to a surface of the self-cleaning, hydrophilic coating.

2. The variable reflectance rearview mirror according to claim 1, wherein the acid resistant layer comprises indium tin oxide.

3. The variable reflectance rearview mirror according to claim 2, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 10:

90% by weight.

4. The variable reflectance rearview mirror according to claim 2, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 20:

80% by weight.

5. The variable reflectance rearview mirror according to claim 2, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 35:

65% by weight.

6. The variable reflectance rearview mirror according to claim 2, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 90:

10% by weight.

7. The variable reflectance rearview mirror according to claim 1, wherein the acid resistant layer comprises tin oxide.

8. The variable reflectance rearview mirror according to claim 1, wherein the acid resistant layer comprises tin silicon oxide.

9. The variable reflectance rearview mirror according to claim 1, wherein the acid resistant layer comprises zirconium silicon oxide.

10. The variable reflectance rearview mirror according to claim 1, wherein the mirror exhibits a C* value of less than approximately 20 in the low reflectance state.

11. The variable reflectance rearview mirror according to claim 1, wherein the mirror exhibits a C* value of less than approximately 20 in both the high reflectance state and the low reflectance state.

12. The variable reflectance rearview mirror according to claim 1, wherein the mirror exhibits a C* value of less than approximately 25 in the low reflectance state.

13. The variable reflectance rearview mirror according to claim 1, wherein the mirror exhibits a C* value of less than approximately 25 in both the high reflectance state and the low reflectance state.

14. The variable reflectance rearview mirror according to claim 1, wherein the mirror exhibits a C* value of greater than approximately 20 in one or more of the high reflectance state and the low reflectance state only if b* contributes to at least approximately 50% of the C* value.

15. The variable reflectance rearview mirror according to claim 1, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 30 degrees.

16. The variable reflectance rearview mirror according to claim 1, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 20 degrees.

17. The variable reflectance rearview mirror according to claim 1, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 10 degrees.

18. An electrochromic device, comprising:

a first substantially transparent element having a front surface and a rear surface, wherein a self-cleaning, hydrophilic coating is applied to at least a portion of the front surface, and further wherein an electrically conductive material is applied to at least a portion of the rear surface;

a second element having a front surface and a rear surface, wherein an electrically conductive material is applied to at least a portion of the front surface;

an electrochromic medium contained within a chamber positioned between the first and second elements; and

an acid resistant layer applied to a surface of the self-cleaning, hydrophilic coating, wherein the acid resistant layer comprises indium tin oxide, and further wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 10;

90% by weight.

19. The electrochromic device according to claim 18, wherein the electrochromic medium comprises at least one solvent, an anodic material, and a cathodic material.

20. The electrochromic device according to claim 18, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 20:

80% by weight.

21. The electrochromic device according to claim 18, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 35:

65% by weight.

22. The electrochromic device according to claim 18, wherein the acid resistant layer comprises a ratio of Sn to In of greater than approximately 90:

10% by weight.

23. The electrochromic device according to claim 18, wherein the mirror exhibits a C* value of less than approximately 20 in a low reflectance state.

24. The electrochromic device according to claim 18, wherein the mirror exhibits a C* value of less than approximately 20 in both a high reflectance state and a low reflectance state.

25. The electrochromic device according to claim 18, wherein the mirror exhibits a C* value of less than approximately 25 in a low reflectance state.

26. The electrochromic device according to claim 18, wherein the mirror exhibits a C* value of less than approximately 25 in both a high reflectance state and a low reflectance state.

27. The electrochromic device according to claim 18, wherein the mirror exhibits a C* value of greater than approximately 20 in one or more of a high reflectance state and a low reflectance state only if b* contributes to at least approximately 50% of the C* value.

28. The electrochromic device according to claim 18, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 30 degrees.

29. The electrochromic device according to claim 18, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 20 degrees.

30. The electrochromic device according to claim 18, wherein the self-cleaning, hydrophilic coating is sufficiently hydrophilic such that water droplets on a front surface of the self-cleaning, hydrophilic coating exhibit a contact angle of less than about 10 degrees.