Electro-optic aperture for vehicular imaging system

• US 6,426,492 B1
• Filed: 01/28/2000
• Issued: 07/30/2002
• Est. Priority Date: 05/24/1999
• Status: Expired due to Fees

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Larson, Mark L., Bos, Brent J.
• Primary Examiner(s): Dang, Hung Xuan
• Application Number:
  US09/493,522
• Time in Patent Office: 914 Days
• Field of Search: 250/208.1, 250/208.2, 250/214.AL, 250/226, 250/229, 326/61, 315/82
• US Class Current: 250/208.1
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0418 using attenuators
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

An electro-optic aperture includes an electrochromic medium at least partially disposed thereon. The electrochromic medium is operable to adjust the transmissivity of light through the aperture in response to an electrical signal applied to the aperture. The aperture preferably is operable to significantly attenuate all wavelengths of energy in an area where the electrochromic medium is energized, thereby allowing the energy to pass through an area of the aperture which either does not include the film or is not being energized. Preferably, the electro-optic aperture is implemented with a silicon imaging array sensor, and functions to improve focusing of images when there is sufficient light available in the scene, while allowing a greater amount of light therethrough when lighting conditions darken. Preferably, the electro-optic aperture is operable to significantly attenuate energy during daytime or other higher intensity lighting conditions, and may be selectively deactivated or otherwise adjusted at nighttime or in other darkened lighting conditions, such that a greater amount of energy may be received by the sensor in order to improve illumination of the image being captured by the sensor.

Claims

1. A vehicular imaging system for capturing an image, comprising:

an imaging sensor;

an electro-optic aperture which is operable to selectively attenuate captured light passing through at least one region of said electro-optic aperture, said electro-optic aperture being positioned along an optic path to said imaging sensor; and

a control applying a signal to said electro-optic aperture.

2. The vehicular imaging system of claim 1 further comprising a focusing lens positioned between said imaging sensor and said electro-optic aperture.

3. The vehicular imaging system of claim 1, wherein said at least one region of electro-optic aperture comprises at least one zone which defines a center region of said electro-optic aperture, said at least one zone selectively attenuating light passing therethrough in response to said control, while said center region of said electro-optic aperture allows substantially non-attenuated light to pass therethrough.

4. The vehicular imaging system of claim 3, wherein said at least one zone comprises multiple zones, each one of said multiple zones being electrically isolated from the other of said zones, said control being operable to selectively apply a signal to each of said multiple zones.

5. The vehicular imaging system of claim 1, wherein said electro-optic aperture comprises an electrochromic medium at least partially disposed on said at least one region of said electro-optic aperture, said electrochromic medium being operable to attenuate light passing therethrough in response to a voltage being applied to said electro-optic aperture.

6. The vehicular imaging system of claim 5, wherein said electrochromic medium comprises at least one of an electrochromic film, an electrochromic solid polymer film, and an electrochromic solution.

7. The vehicular imaging system of claim 5, wherein said electrochromic medium is energizable to attenuate light through at least one outer circumferential region of said electro-optic aperture while a center region of said electro-optic aperture allows light to pass therethrough, said center region being defined by said at least one outer circumferential region.

8. The vehicular imaging system of claim 7, wherein said at least one outer circumferential region comprises multiple regions of said electrochromic medium, said control selectively applying a voltage to each said region to attenuate light through that region, said electro-optic aperture allowing inwardly positioned regions to pass light therethrough.

9. The vehicular imaging system of claim 7, wherein said control is operable to adjust the signal applied to said electro-optic aperture in response to a change in an ambient energy intensity.

10. The vehicular imaging system of claim 9, wherein said imaging sensor comprises a photon accumulating sensor.

11. The vehicular imaging system of claim 10, wherein said imaging sensor comprises a color sensor, said imaging system further including a color filter.

12. The vehicular imaging system of claim 1, wherein said electro-optic aperture comprises first and second opposing counter conducting electrodes, an electrochromically active material layer disposed on an opposing surface of said first conducting electrode and an electrolyte contactedly disposed between said electrochromically active material layer and an opposing surface of said second conducting electrode, at least one of said first and second counter conducting electrodes being partially disposed on at least one of said electrochromically active material and said electrolyte to define said at least one region.

13. The vehicular imaging system of claim 12, wherein said first counter conducting electrode is partially disposed on said electrochromically active material and said second counter conducting electrode is partially disposed on said electrolyte.

14. The vehicular imaging system of claim 12, wherein said electro-optic aperture further comprises a first substrate disposed on an outer surface of said first conducting electrode and a second substrate disposed on an outer surface of said second conducting electrode.

15. The vehicular imaging system of claim 12, wherein said first and second conducting electrodes comprise one of a doped Indium Oxide, a doped Tin Oxide and a doped Zinc Oxide.

16. The vehicular imaging system of claim 12, wherein said first and second conducting electrodes comprise Indium Tin Oxide.

17. The vehicular imaging system of claim 12, wherein said electrolyte comprises a redox active material.

18. The vehicular imaging system of claim 17, wherein said redox active material comprises Ferrocene.

19. The vehicular imaging system of claim 12, wherein said electrochromically active material layer comprises an inorganic metal oxide which is selected from at least one of WO₃, V₂O₅, MoO₃, Nb₂O₅, TiO₂, CuO, Ni₂O₃, Ir₂O₃, Cr₂O₃, Co₂O₃, and Mn₂O₃.

20. The vehicular imaging system of claim 19, wherein said first and second conducting electrodes comprise Indium Tin Oxide.

21. The vehicular imaging system of claim 20, wherein said electrolyte comprises a redox active material.

22. The vehicular imaging system of claim 21, wherein said redox active material comprises Ferrocene.

23. The vehicular imaging system of claim 1, wherein said electro-optic aperture comprises a solid state electrochromic aperture.

24. A vehicular imaging system for capturing an image, comprising:

an imaging array sensor;

a focusing lens positioned along an optic path to said imaging array sensor;

an electro-optic aperture operable to attenuate a portion of captured energy in at least one region of said electro-optic aperture, said focusing lens being positionable along an optic path between said imaging array sensor and said electro-optic aperture; and

a control which is operable to at least occasionally apply a signal to said electro-optic aperture.

25. The vehicular imaging system of claim 24, wherein said control is operable to process an image received by said imaging array sensor and communicate an output signal to a receiving circuit.

26. The vehicular imaging system of claim 24, wherein said imaging array sensor is a pixelated array sensor comprising a plurality of photo-sensing pixels.

27. The vehicular imaging system of claim 26, wherein said imaging array sensor includes a color filter, said control being operable to determine the colors associated with the image sensed by said imaging array pixels.

28. The vehicular imaging system of claim 24, wherein said electro-optic aperture comprises an electrochromic medium which is operable to attenuate energy in response the signal being applied to said electro-optic aperture.

29. The vehicular imaging system of claim 28, wherein said control selectively applies the signal to said electro-optic aperture in response to a change in an ambient energy intensity.

30. The vehicular imaging system of claim 29, wherein the signal is continuously adjustable in response to said change in ambient energy intensity.

31. The vehicular imaging system of claim 24, wherein said electro-optic aperture comprises first and second conducting electrodes disposed on a respective side of an electrochromically active material layer and an electrolyte, at least one of said first and second conducting electrodes being partially disposed on the respective side of said electrochromically active material layer and said electrolyte.

32. The vehicular imaging system of claim 31, wherein said first conducting electrode is partially disposed on the respective side of said electrochromically active material layer and said second conducting electrode is correspondingly partially disposed on the respective side of said electrolyte.

33. The vehicular imaging system of claim 31, wherein said first and second conducting electrodes comprise Indium Tin Oxide, said electrochromically active material layer at least partially comprises Tungsten Oxide, and said electrolyte comprises Ferrocene.

34. The vehicular imaging system of claim 24, wherein said control selectively applies the signal to said electro-optic aperture in response to a change in an ambient energy intensity.

35. The vehicular imaging system of claim 24 further comprising a plurality of electro-optic apertures positionable along said optic path, each of said plurality of electro-optic apertures being operable to attenuate a different region of the captured energy from another of said plurality of electro-optic apertures.

36. The vehicular imaging system of claim 24, wherein said at least one region comprises at least one ring which is operable to attenuate energy passing therethrough while an inner region allows substantially non-attenuated energy to pass therethrough, said inner region being surrounded and defined by said at least one ring.

37. The vehicular imaging system of claim 36, wherein said at least one ring comprises multiple electronically isolated rings, said control being operable to selectively apply the signal to one or more of said multiple rings.

38. The vehicular imaging system of claim 24, wherein said electro-optic aperture comprises a solid state electrochromic aperture.

39. A vehicular imaging system for capturing an image, comprising:

an imaging sensor which is operable to capture the image;

a focusing lens, said focusing lens being operable to focus the image onto said imaging sensor, said focusing lens being positioned along an optic path to said imaging sensor;

an electrochromic aperture which comprises at least one outer region and an inner region, said focusing lens being positioned along an optic path between said electrochromic aperture and said imaging sensor; and

a control which is operable to energize said electrochromic aperture by applying a signal thereto, said electrochromic aperture being operable to attenuate energy in said at least one outer region when said electrochromic aperture is energized while allowing substantially non-attenuated energy to pass through said inner region.

40. The vehicular imaging system of claim 39, wherein said control is operable to selectively energize said electrochromic aperture.

41. The vehicular imaging system of claim 40, wherein said control is operable to selectively energize said electrochromic aperture in response to an ambient illumination level.

42. The vehicular imaging system of claim 41, wherein said control energizes said electrochromic aperture when said ambient illumination level is above a threshold level, said control de-energizing said electrochromic aperture when said ambient illumination level is below said threshold level.

43. The vehicular imaging system of claim 42, wherein said electrochromic aperture comprises an electrochromic medium which is disposed in said at least one outer region of said aperture.

44. The vehicular imaging system of claim 43, wherein said electrochromic medium is disposed between a pair of conducting electrodes, said conducting electrodes being partially disposed at said electrochromic medium to define said at least one outer region.

45. The vehicular imaging system of claim 44, wherein said at least one outer region comprises multiple rings of conducting electrodes, said control being operable to selectively address at least one of said multiple rings.

46. The vehicular imaging system of claim 45, wherein said control is operable to selectively address said rings in response to said ambient illumination level.

47. The vehicular imaging system of claim 39, wherein said electrochromic aperture comprises a layer of electrochromic medium at least partially disposed in said at least one outer region of said aperture.

48. The vehicular imaging system of claim 47, wherein said electrochromic medium is disposed between a pair of conducting electrodes, said conducting electrodes being at least partially disposed at said electrochromic medium to define said at least one outer region.

49. The vehicle imaging system of claim 48, wherein said at least one outer region comprises multiple rings of conducting electrodes, said control being operable to selectively address at least one of said multiple rings.

50. The vehicular imaging system of claim 39, wherein said imaging sensor comprises an imaging array sensor.

51. The vehicular imaging system of claim 39, wherein said electrochromic aperture comprises first and second opposing conducting electrodes, an electrochromically active material layer disposed on an opposing surface of said first conducting electrode and an electrolyte contactedly disposed between said electro-chemically active material layer and an opposing surface of said second conducting electrode, said first electrode being counter conducting to said second electrode, at least one of said first and second counter conducting electrodes being partially disposed on at least one of said electrochromically active material layer and said electrolyte, said at least one of said first and second counter conducting electrodes defining said at least one outer region of said electrochromic aperture.

52. The vehicular imaging system of claim 51, wherein said first counter conducting electrode is partially disposed on said electrochromically active material layer and said second counter conducting electrode is correspondingly partially disposed on said electrolyte.

53. The vehicular imaging system of claim 51, wherein said at least one outer region comprises multiple regions, each of said multiple regions comprising an electrically isolated zone of the first and second counter conducting electrodes, said control being operable to selectively address one or more of said multiple regions to radially vary the size of said inner region.

54. The vehicular imaging system of claim 51, wherein said electrochromic aperture further comprises a first substrate disposed on an outer surface of said first conducting electrode and a second substrate disposed on an outer surface of said second conducting electrode.

55. The vehicular imaging system of claim 51, wherein said first and second conducting electrodes comprise one of a doped Indium Oxide, a doped Tin Oxide and a doped Zinc Oxide.

56. The vehicular imaging system of claim 51, wherein said first and second conducting electrodes comprise Indium Tin Oxide.

57. The vehicular imaging system of claim 51, wherein said electrolyte includes a redox active material.

58. The vehicular imaging system of claim 57, wherein said redox active material is Ferrocene.

59. The vehicular imaging system of claim 51, wherein said electrochromically active material layer is an inorganic metal oxide which is selected from at least one of WO₃, V₂O₅, MoO₃, Nb₂O₅, TiO₂, CuO, Ni₂O₃, Ir₂O₃, Cr₂O₃, Co₂O₃, and Mn₂O₃.

60. The vehicular imaging system of claim 59, wherein said first and second conducting electrodes comprise Indium Tin Oxide.

61. The vehicular imaging system of claim 60, wherein said electrolyte includes a redox active material.

62. The vehicular imaging system of claim 61, wherein said redox active material is Ferrocene.

63. The vehicular imaging system of claim 39 further including a plurality of electrochromic apertures positionable along said optic path, each of said plurality of electrochromic apertures comprising an outer region defining a different sized inner region from another of said plurality of electrochromic apertures.

64. The vehicular imaging system of claim 63, wherein said control is operable to selectively energize each of said plurality of electrochromic apertures.

65. The vehicular imaging system of claim 63, wherein said control is operable to selectively energize each of said plurality of electrochromic apertures in response to an ambient illumination level.

66. The vehicular imaging system of claim 39, wherein said electrochromic aperture comprises a solid state electrochromic aperture.