Variable reflectance mirrors and windows

• US 20060007550A1
• Filed: 07/12/2005
• Published: 01/12/2006
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Tonar, William L., Bauer, Frederick T., Watson, Alan R.
• Granted Patent: US 7,502,156 B2
• 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

Abstract

Various structures for variable reflectance rearview mirrors and variable transmittance windows are disclosed. One embodiment pertains to the provision of a polarized reflector in a rearview mirror. Another embodiment pertains to the provision of a switchable cholesteric liquid crystal element in a window. Yet another embodiment pertains to the provision of a plurality of apertures in a reflector layer of a rearview mirror where the apertures are sized and positioned in alignment with light emitting areas of a display positioned behind the reflector layer. In another embodiment, a moveable display or mirror element is attached to a rearview mirror housing.

Claims

1. A variable reflectance mirror element for use in a rearview mirror assembly having an electronic device positioned behind the mirror element for transmitting/receiving light of a first polarization, said mirror element comprising:

a first substrate;

a second substrate;

a first electrode provided on a surface of said first substrate;

a second electrode provided on a surface of said second substrate;

an electro-optic medium provided between said first and second substrates that changes transmittance in response to a voltage applied across said first and second electrodes; and

a polarized reflector provided on a surface of said second substrate for transmitting light of the first polarization and reflecting light of a second polarization opposite the first polarization.

2. The mirror element of claim 1, wherein said polarized reflector is electrically conductive and functions as said second electrode.

3. The mirror element of claim 1, wherein said polarized reflector is a wire grid polarizer.

4. The mirror element of claim 1, wherein said electro-optic element comprises an electrochromic element.

5. The mirror element of claim 4, wherein said electro-optic element further comprises a switchable cholesteric liquid crystal element, which also functions as said polarized reflector.

6. The mirror element of claim 1, wherein said electro-optic element comprises a switchable cholesteric liquid crystal element, which also functions as said polarized reflector.

7. The mirror element of claim 1, wherein said electro-optic element comprises a first switchable cholesteric liquid crystal element, which also functions as said polarized reflector, and a second switchable cholesteric liquid crystal element.

8. A rearview mirror assembly for a vehicle comprising:

an electro-optic element comprising first and second electrodes, said electro-optic element changes reflectance in response to a voltage applied across said first and second electrodes, wherein said second electrode comprises a polarized reflector for transmitting light of a first polarization and reflecting light of a second polarization opposite the first polarization; and

an electronic device positioned behind said polarized reflector for transmitting/receiving light of the first polarization through said polarized reflector.

9. The rearview mirror assembly of claim 8, wherein said electronic device is a light sensor.

10. The rearview mirror assembly of claim 9, wherein said light sensor is positioned to sense glare light levels from the rear of the vehicle.

11. The rearview mirror assembly of claim 8, wherein said electronic device is a display.

12. The rearview mirror assembly of claim 11, wherein said display is a compass display.

13. The rearview mirror assembly of claim 11, wherein said display is a video display.

14. The rearview mirror assembly of claim 11, wherein said display is a rear vision display.

15. The rearview mirror assembly of claim 11, wherein said display is a liquid crystal display.

16. The rearview mirror assembly of claim 8, wherein said electronic device is a light source.

17. The rearview mirror assembly of claim 8, wherein said light source is a turn signal.

18. The rearview mirror assembly of claim 8, wherein said electro-optic element comprises an electrochromic element.

19. The rearview mirror assembly of claim 8, wherein said polarized reflector is a wire grid polarizer.

20. The rearview mirror assembly of claim 8, wherein said electro-optic element comprises a switchable cholesteric liquid crystal element, which also serves as said polarized reflector.

21. The rearview mirror assembly of claim 8, wherein said electro-optic element comprises a first switchable cholesteric liquid crystal element, which also functions as said polarized reflector, and a second switchable cholesteric liquid crystal element.

22. An electrochromic element comprising:

a first substrate;

a second substrate spaced apart from said first substrate;

a first electrode provided on a surface of said first substrate;

a second electrode provided on a surface of said second substrate;

an electrochromic medium provided between said first and second substrates; and

a polarized reflector provided on a surface of one of said first and second substrates, said polarized reflector transmits light of a first polarization and reflects light of a second polarization opposite the first polarization.

23. The electrochromic element of claim 22, wherein said polarized reflector comprises a wire grid polarizer.

24. The electrochromic element of claim 22, wherein said polarized reflector comprises a switchable cholesteric liquid crystal element.

25. A rearview mirror assembly for a vehicle comprising:

a housing adapted for attachment to the vehicle;

a display positioned within the housing; and

a mirror element moveably mounted to said housing, said mirror element movable between a first position in front of said display, and a second position away from said display.

26. A rearview mirror assembly for a vehicle comprising:

a housing adapted for attachment to the vehicle;

a mirror element positioned within the housing; and

a display moveably mounted to said housing, said display movable between a first position where said display may be viewed by a vehicle occupant, and a second position where said display may not be readily viewed by a vehicle occupant.

27. The rearview mirror assembly of claim 26, wherein said display is mounted to said housing so as to pivot from the first position, which is below said mirror housing, to the second position, which is behind the mirror housing.

28. The rearview mirror assembly of claim 26, wherein said display is moved automatically from the second position to the first position when the vehicle is placed in reverse.

29. The rearview mirror assembly of claim 28, wherein said display is configured to be moved manually from the first position to the second position when the vehicle is no longer in reverse.

30. An electro-optic variable transmittance window comprising a switchable cholesteric element having a pitch that varies in response to an applied voltage so as to vary the transmittance of the electro-optic variable transmittance window.

31. The electro-optic variable transmittance window of claim 30, wherein said window is a vehicle window.

32. The electro-optic variable transmittance window of claim 30, wherein said window is an airplane window.

33. The electro-optic variable transmittance window of claim 30, wherein said window is a sunroof.

34. The electro-optic variable transmittance window of claim 30, wherein said window is an architectural window.

35. The electro-optic variable transmittance window of claim 30, wherein said switchable cholesteric element comprises:

a first substrate having a first surface and a second surface;

a second substrate having a first surface and a second surface, the first surface of said second substrate facing the second surface of said first substrate;

a first electrode positioned on the second surface of said first substrate;

a second electrode positioned on the first surface of said second substrate;

a first orientation layer disposed on said first electrode;

a second orientation layer disposed on said second electrode; and

a mixture of cholesteric liquid crystalline molecules disposed between said orientation layers.

36. The electro-optic variable transmittance window of claim 30, wherein said window is an insulated window.

37. The electro-optic variable transmittance window of claim 36, wherein said insulated window comprises:

a first pane;

a second pane, spaced from said first pane;

wherein said switchable cholesteric element is positioned between said first and second panes with a chamber provided between said switchable cholesteric element and one of said first and second panes.

38. The electro-optic variable transmittance window of claim 37, wherein said switchable cholesteric element is positioned adjacent said first pane with a chamber provided between said switchable cholesteric element and said second pane.

39. The electro-optic variable transmittance window of claim 38, wherein said switchable cholesteric element constitutes a first switchable cholesteric element and said electro-optic variable transmittance window further comprises a second switchable cholesteric element positioned between said first switchable cholesteric element and said second pane.

40. The electro-optic variable transmittance window of claim 39, wherein said second switchable cholesteric element is positioned adjacent said first switchable cholesteric element with a chamber provided between said second switchable cholesteric element and said second pane.

41. The electro-optic variable transmittance window of claim 39, wherein said second switchable cholesteric element is positioned adjacent said second pane with a chamber provided between said first and second switchable cholesteric elements.

42. The electro-optic variable transmittance window of claim 37, wherein said switchable cholesteric element constitutes a first switchable cholesteric element and said electro-optic variable transmittance window further comprises a second switchable cholesteric element positioned between said first and second panes.

43. The electro-optic variable transmittance window of claim 30 and further comprising a shatter-proof substrate positioned adjacent said switchable cholesteric element.

44. A rearview mirror assembly for a vehicle comprising:

a substrate;

a reflective layer applied to a surface of said substrate; and

a display having a plurality of light emitting areas,

wherein said reflective layer has a plurality of apertures formed therethrough, each aperture being associated and substantially aligned with the light emitting regions of said display.

45. The rearview mirror assembly of claim 44, wherein said substrate constitutes a second substrate, said second substrate having a first surface and a second surface, and said rearview mirror assembly further comprises:

a first substrate spaced from said second substrate, said first substrate having first and second surfaces with the second surface of said first substrate facing the first surface of said second substrate; and

an electro-optic medium disposed between said first and second substrates,

wherein said reflective layer is applied to one of the surfaces of said second substrate, and

wherein said display is positioned behind the second surface of said second substrate.

46. The rearview mirror assembly of claim 45, wherein said reflective layer is applied to the second surface of said second substrate.

47. The rearview mirror assembly of claim 45, wherein said reflective layer is applied to the first surface of said second substrate.

48. The rearview mirror assembly of claim 45, wherein said electro-optic medium is an electrochromic medium.

49. The rearview mirror assembly of claim 44 and further comprising an optical device positioned between said display and said reflective layer, said optical device comprising a plurality of lenses for converging the light emitted from the light emitting areas of said display.

50. The rearview mirror assembly of claim 44 and further comprising a transflective layer disposed within or behind said apertures.

51. The rearview mirror assembly of claim 44 and further comprising a second reflective layer provided on a surface of said display except in the light emitting areas of said display, and wherein said display is moveably mounted relative to said substrate.

52. A rearview mirror assembly for a vehicle comprising:

a substrate;

a reflective layer applied to a surface of said substrate, wherein said reflective layer has a plurality of apertures formed therethrough;

a display positioned behind said reflective layer; and

a material that is at least partially reflective disposed in said apertures.

53. The rearview mirror assembly of claim 52, wherein each said aperture is associated and substantially aligned with light emitting regions of said display.

54. The rearview mirror assembly of claim 52, wherein said material is selectively disposed in said apertures.

55. The rearview mirror assembly of claim 54, wherein said material is a reversible electro-deposition material.

56. The rearview mirror assembly of claim 54, wherein said material is a digital paper material.

57. The rearview mirror assembly of claim 54, wherein said material is applied as a second reflective layer on a surface of said display with the exception of light emitting areas on said display, and wherein said display is moved relative to said substrate to thereby move said second reflective layer into and out of alignment with said apertures.

58. The rearview mirror assembly of claim 52, wherein said material is applied as a transflective layer on said substrate at least within said apertures.