Reduced ultraviolet radiation transmitting, electrochromic assembly

• US 5,680,245 A
• Filed: 03/18/1996
• Issued: 10/21/1997
• Est. Priority Date: 02/12/1988
• Status: Expired due to Fees

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Lynam, Niall R.
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): Lester, Evelyn A.
• Application Number:
  US08/617,333
• Time in Patent Office: 582 Days
• Field of Search: 359/265-275
• US Class Current: 359/265
• CPC Class Codes: B32B 17/10005 laminated safety glass or glazing
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10064 comprising at least two glass sheets, only one of which being an outer layer
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B32B 17/10302 Edge sealing
• CPC Class Codes: B32B 17/1033 Laminated safety glass or glazing containing temporary protective coatings or layers
• CPC Class Codes: B32B 17/10339 Specific parts of the laminated safety glass or glazing being colored or tinted tinted glass sheet B32B17/1011; tinted interlayer B32B17/10651
• CPC Class Codes: B32B 17/10513 Electrochromic layer
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B32B 2367/00 Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B60J 3/04 adjustable in transparency
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2001/1536 additional, e.g. protective, layer inside the cell

Abstract

An electrochromic assembly which is useful, for example, as a rearview mirror or glazing is disclosed with reduced ultraviolet (UV) radiation degradation and reduced fogging or misting in high humidity conditions. The assembly may include a pair of glass or other elements confining an electrochromic medium therebetween. Ultraviolet radiation is preferably reduced by a sheet of specialized glass which may include higher iron oxide or cerium oxide content than conventional soda lime window glass. The specialized glass is preferably a tinted glass that absorbs substantially more light in those regions of the visible spectrum higher than about 560 nanometers than in other regions of the visible spectrum. An anti-fogging additive may also be included in the assembly.

Claims

1. A reduced ultraviolet radiation transmitting electrochromic assembly, said assembly comprising:

first and second spaced, optically transparent elements, said elements having facing surfaces defining a space between said first and second elements;

an electrochromic medium confined in said space whose light transmittance is variable upon the application of an electric field thereto;

means for applying an electric field to said electrochromic medium to cause variation in the light transmittance of said medium;

ultraviolet radiation reducing means incorporated in said assembly for reducing ultraviolet radiation degradation of said electrochromic medium in said assembly;

said ultraviolet radiation reducing means comprising a sheet of specialized glass, said specialized glass sheet being transmitting in the visible portion of the electromagnetic spectrum but having reduced transmission in the ultraviolet portion of the electromagnetic spectrum.

2. The electrochromic assembly of claim 1 wherein said specialized glass is selected from the group consisting of glass having an iron oxide content of at least 0.2% by weight, and glass having a cerium oxide content of at least 0.2% by weight.

3. The electrochromic assembly of claim 1 wherein said specialized glass comprises glass having a titanium oxide content of at least 0.2% by weight.

4. The electrochromic assembly of claim 1 wherein said specialized glass comprises glass having an iron oxide content in the range of between about 0.2% to 2.0% by weight.

5. The electrochromic assembly of claim 1 wherein said specialized glass comprises glass having a cerium oxide content in the range of between about 0.2% to 2.0% by weight.

6. The electrochromic assembly of claim 1 wherein said first element is located closer to a source of ultraviolet radiation than said second element.

7. The electrochromic assembly of claim 6 wherein said assembly further includes an anti-fogging additive.

8. The electrochromic assembly of claim 1 wherein said assembly includes spectrally selective absorbing means for absorbing a predetermined amount of light in those regions of the visible spectrum from about 400 nanometers to about 560 nanometers, and for absorbing an amount of light which is greater than said predetermined amount in those regions of the visible spectrum from about 560 nanometers to about 780 nanometers.

9. The electrochromic assembly of claim 8 wherein said spectrally selective absorbing means comprises a tinted glass sheet.

10. The electrochromic assembly of claim 9 wherein said specialized glass sheet comprises said tinted glass sheet.

11. The electrochromic assembly of claim 1 wherein at least one of said first element and said second element comprises a tinted glass sheet which absorbs a predetermined amount of visible light in wavelengths higher than about 560 nanometers, and absorbs an amount of light less than said predetermined amount in other regions of the visible spectrum.

12. The electrochromic assembly of claim 11 wherein said tinted glass sheet has a blue tint.

13. The electrochromic assembly of claim 11 wherein said tinted glass sheet has a green tint.

14. The electrochromic assembly of claim 1 wherein at least one of said first element and said second element comprises a tinted glass sheet.

15. The electrochromic assembly of claim 14 wherein said tinted glass sheet has a tint selected from the group consisting of a blue tint, a green tint and a gray tint.

16. The electrochromic assembly of claim 1 wherein said means for applying an electric field includes a transparent conductive coating comprising a doped tin oxide on at least one of said facing surfaces of said first and second elements.

17. The electrochromic assembly of claim 1 wherein said assembly is a rearview minor assembly.

18. The electrochromic assembly of claim 1 wherein said assembly is a glazing assembly.

19. A reduced ultraviolet radiation transmitting electrochromic assembly, said assembly comprising:

first and second spaced, optically transparent elements, said elements having facing surfaces defining a space between said first and second elements, and wherein said first element is located closer to a source of ultraviolet radiation than said second element;

an electrochromic medium confined in said space whose light transmittance is variable upon the application of an electric field thereto;

means for applying an electric field to said electrochromic medium to cause variation in the light transmittance of said medium;

ultraviolet radiation reducing means incorporated in said assembly for reducing ultraviolet radiation degradation of said electrochromic medium in said assembly;

said ultraviolet radiation reducing means comprising said first element being a sheet of specialized glass, said specialized glass sheet being transmitting in the visible portion of the electromagnetic spectrum but having reduced transmission in the ultraviolet portion of the electromagnetic spectrum; and

wherein said specialized glass is selected from the group consisting of glass having an iron oxide content of at least 0.2% by weight, and glass having a cerium oxide content of at least 0.2% by weight.

20. The electrochromic assembly of claim 19 wherein said assembly includes spectrally selective absorbing means for absorbing a predetermined amount of light in those regions of the visible spectrum from about 400 nanometers to about 560 nanometers, and for absorbing an amount of light which is greater than said predetermined amount in those regions of the visible spectrum from about 560 nanometers to about 780 nanometers.

21. The electrochromic assembly of claim 20 wherein said spectrally selective absorbing means comprises a tinted glass sheet.

22. The electrochromic assembly of claim 21 wherein said specialized glass sheet comprises said tinted glass sheet.

23. The electrochromic assembly of claim 19 wherein at least one of said first element and said second element comprises a tinted glass sheet which absorbs a predetermined amount of visible light in wavelengths higher than about 560 nanometers, and absorbs an amount of light less than said predetermined amount in other regions of the visible spectrum.

24. The electrochromic assembly of claim 23 wherein said tinted glass sheet has a blue tint.

25. The electrochromic assembly of claim 23 wherein said tinted glass sheet has a green tint.

26. The electrochromic assembly of claim 19 wherein at least one of said first element and said second element comprises a tinted glass sheet.

27. The electrochromic assembly of claim 26 wherein said tinted glass sheet has a tint selected from the group consisting of a blue tint, a green tint and a gray tint.

28. The electrochromic assembly of claim 19 wherein said means for applying an electric field includes a transparent conductive coating comprising a doped tin oxide on at least one of said facing surfaces of said first and second elements.

29. The electrochromic assembly of claim 19 wherein said specialized glass comprises glass having an iron oxide content in the range of between about 0.2% to 2.0% by weight.

30. The electrochromic assembly of claim 19 wherein said specialized glass comprises glass having a cerium oxide content in the range of between about 0.2% to 2.0% by weight.

31. The electrochromic assembly of claim 19 wherein said assembly is a rearview mirror assembly.

32. The electrochromic assembly of claim 19 wherein said assembly is a glazing assembly.

33. The electrochromic assembly of claim 19 wherein said assembly further includes an anti-fogging additive.