Variable reflectance mirrors and windows

• US 7,679,809 B2
• Filed: 08/14/2008
• Issued: 03/16/2010
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Bauer, Fredrick T., Tonar, William L., Watson, Alan R.
• Primary Examiner(s): Pritchett; Joshua L
• Application Number:
  US12/191,804
• Publication Number:
  US 20090002822A1
• Time in Patent Office: 579 Days
• Field of Search: 359/267, 359/265, 359/604
• US Class Current: 359/267
• 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 or receiving light of a first polarization, the mirror element comprising:

a first substrate having first and second surfaces;

a second substrate having third and fourth surfaces, the second and first substrates positioned in a spaced-apart relationship such that the second and third surfaces face each other;

a first electrode carried on a surface of the first substrate;

a second electrode carried on a surface of the second substrate,

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

a reflective polarizer for substantially transmitting light of a first polarization and substantially reflecting light of a second polarization, the second polarization being opposite the first polarization, the reflective polarizer disposed on or near the second substrate such that the electronic device transmits or receives light of the first polarization through the reflective polarizer,

wherein the reflective polarizer includes multiple layers of plastic film.

2. A variable reflectance mirror element according to claim 1, wherein the reflective polarizer is laminated to the second substrate proximate the third surface.

3. A variable reflectance mirror element according to claim 1, wherein the reflective polarizer is laminated to the second substrate proximate the fourth surface.

4. A variable reflectance mirror element according to claim 1, wherein the reflective polarizer is laminated to the electronic device.

5. A variable reflectance mirror element according to claim 1, wherein the electronic device is a liquid crystal display.

6. A variable reflectance mirror element according to claim 1, further comprising a switchable cholesteric element including a cholesteric medium, the switchable cholesteric element disposed between the electro-optical medium and the electronic device.

7. A variable reflectance mirror element according to claim 6, wherein the mirror element is characterized by a reflectivity that can be set to any specified value within a range.

8. A variable reflectance mirror element according to claim 6, wherein the mirror element is characterized by at least three discrete states of reflectivity.

9. A variable reflectance mirror element according to claim 1, wherein the cholesteric medium is characterized by a variable pitch.

10. A variable reflectance mirror element according to claim 1, the mirror element configured within a rearview mirror assembly further comprising at least one device selected from the group consisting of an interior illumination assembly, an exterior light control, a moisture sensor, an information display, a light sensor, a blind spot indicator, a turning signal indicator, an approach warning, an operator interface, a compass, a temperature indicator, a voice actuated device, a microphone, a dimming circuitry, a GPS device, a telecommunication system, a navigation aid, a lane departure warning system, an adaptive cruise control, a vision system, a rear vision system and a tunnel detection system.

11. A variable reflectance mirror element according to claim 10, wherein an overall reflection, by the mirror element, of light incident on the first surface is at least sixty percent.

12. A variable reflectance element according to claim 1, wherein the mirror element is characterized by a transmittance that is a function of voltage applied between the first and second electrodes.

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

a first substrate having first and second surfaces;

a second substrate having third and fourth surfaces, the second and first substrates positioned in a spaced-apart relationship such that the second and third surfaces face each other;

a first electrode carried on a the first substrate;

a second electrode carried on the second substrate,

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

a reflective polarizer for substantially transmitting light of a first polarization and substantially reflecting light of a second polarization, the second polarization being opposite the first polarization, the reflective polarizer disposed on or near the second substrate such that the electronic device transmits or receives light of the first polarization through the reflective polarizer, the reflective polarizer laminated to the second substrate.

14. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer is laminated to the third surface.

15. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer is laminated to the fourth surface.

16. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer comprises multiple layers of plastic film.

17. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer includes a wire-gild polarizer.

18. A variable reflectance mirror element according to claim 13, wherein the electronic device is a liquid crystal display.

19. A variable reflectance mirror element according to claim 18, wherein the liquid crystal display is a video display.

20. A variable reflectance mirror element according to claim 18, wherein an area of the liquid crystal display is substantially equal to a viewing area of the variable reflectance mirror element.

21. A variable reflectance mirror element according to claim 18, wherein the liquid crystal display is characterized by a width between 6 and 14 inches and a width-to-height ratio between 2:

1 and 12;

1.

22. A variable reflectance mirror element according to claim 21, wherein the width-to-height ratio of the liquid crystal display is between 3:

1 and 6;

1.

23. A variable reflectance mirror element according to claim 21, wherein the width-to-height ratio of the liquid crystal display is between 4:

1 and 5;

1.

24. A variable reflectance mirror element according to claim 18, wherein the liquid crystal display is backlit with light-emitting diodes.

25. A variable reflectance mirror element according to claim 13, further comprising at least one optical thin film disposed next to the reflective polarizer so as to enhance a reflectivity of the reflective polarizer.

26. A variable reflectance mirror element according to claim 25, wherein the at least one optical thin film includes a dichroic thin-film stack.

27. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer comprises a switchable cholesteric element including a cholesteric medium, the switchable cholesteric element disposed between the electro-optical medium and the electronic device.

28. A variable reflectance mirror element according to claim 27, wherein the cholesteric medium is characterized by a variable pitch.

29. A variable reflectance mirror element according to claim 27, wherein the mirror element is characterized by a reflectivity that can be set to any specified value within a range.

30. A variable reflectance mirror element according to claim 27, wherein the mirror element is characterized by at least three discrete states of reflectivity.

31. A variable reflectance mirror element according to claim 27, wherein an overall reflection, by the mirror element, of light incident on the first surface is at least sixty percent.

32. A variable reflectance mirror element according to claim 13, the mirror element configured within a rearview mirror assembly further comprising at least one device selected from the group consisting of an interior illumination assembly, an exterior light control, a moisture sensor, an information display, a light sensor, a blind spot indicator, a turning signal indicator, an approach warning, an operator interface, a compass, a temperature indicator, a voice actuated device, a microphone, a dimming circuitry, a GPS device, a telecommunication system, a navigation aid, a lane departure warning system, an adaptive cruise control, a vision system, a rear vision system and a tunnel detection system.

33. A variable reflectance mirror element according to claim 13, wherein the reflective polarizer functions as the second electrode.

34. A variable reflectance element according to claim 13, wherein the mirror element is characterized by a transmittance that is a function of voltage applied between the first and second electrodes.

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

a first substrate having first and second surfaces;

a second substrate having third and fourth surfaces, the second and first substrates positioned in a spaced-apart relationship such that the second and third surfaces face each other;

a first electrode carried on a surface of the first substrate;

a second electrode carried on a surface of the second substrate;

an electrochromic medium provided between the first and second substrates;

a reflective polarizer for substantially transmitting light of a first polarization and substantially reflecting light of a second polarization, the second polarization being opposite the first polarization, the reflecting polarizer positioned on or near the second substrate such that the electronic device transmits or receives light of the first polarization through the reflective polarizer; and

at least one optical film enhancing a reflectivity of the reflective polarizer.

36. A variable reflectance mirror element according to claim 35, wherein the mirror element is characterized by a reflectance of at least fifty percent.

37. A variable reflectance mirror element according to claim 36, the mirror element configured within a rearview mirror assembly further comprising at least one device selected from the group consisting of an interior illumination assembly, an exterior light control, a moisture sensor, an information display, a light sensor, a blind spot indicator, a turning signal indicator, an approach warning, an operator interface, a compass, a temperature indicator, a voice actuated device, a microphone, a dimming circuitry, a GPS device, a telecommunication system, a navigation aid, a lane departure warning system, an adaptive cruise control, a vision system, a rear vision system and a tunnel detection system.

38. A variable reflectance mirror element according to claim 35, wherein the mirror element is characterized by a reflectance of at least sixty percent.

39. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer includes multiple layers of plastic film.

40. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer includes a wire-grid polarizer.

41. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer is laminated to the fourth surface.

42. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer is laminated to the third surface.

43. A variable reflectance mirror element according to claim 35, wherein the electronic device is a liquid crystal display.

44. A variable reflectance mirror element according to claim 43, wherein the liquid crystal display is a video display.

45. A variable reflectance mirror element according to claim 43, wherein an area of the liquid crystal display is substantially equal to a viewing area of the variable reflectance mirror element.

46. A variable reflectance mirror element according to claim 43, wherein the liquid crystal display is characterized by a width between 6 and 14 inches and a width-to-height ratio of the liquid crystal display is between 2:

1 and 12;

1.

47. A variable reflectance mirror element according to claim 46, wherein the width-to-height ratio of the liquid crystal display is between 3:

1 and 6;

1.

48. A variable reflectance mirror element according to claim 46, wherein the width-to-height ratio of the liquid crystal display is between 4:

1 and 5;

1.

49. A variable reflectance mirror element according to claim 43, wherein the liquid crystal display is backlit with light-emitting diodes.

50. A variable reflectance mirror element according to claim 35, wherein the at least one optical thin film includes a dichroic thin-film stack.

51. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer functions as the second electrode.

52. A variable reflectance mirror element according to claim 35, wherein the reflective polarizer comprises a switchable cholesteric element including a cholesteric medium, the switchable cholesteric element disposed between the electro-optical medium and the electronic device.

53. A variable reflectance mirror element according to claim 52, wherein the cholesteric medium is characterized by a variable pitch.

54. A variable reflectance mirror element according to claim 52, wherein the mirror element is characterized by a reflectivity that can be set to any specified value within a range.

55. A variable reflectance mirror element according to claim 52, wherein the mirror element is characterized by at least three discrete states of reflectivity.

56. A variable reflectance element according to claim 35, wherein the mirror element is characterized by a transmittance that is a function of voltage applied between the first and second electrodes.