Electro-optic filter for vehicle imaging system

• US 6,667,471 B2
• Filed: 07/26/2002
• Issued: 12/23/2003
• Est. Priority Date: 05/24/1999
• Status: Expired due to Term

• 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:
  US10/206,558
• Publication Number:
  US 20020185587A1
• Time in Patent Office: 515 Days
• Field of Search: 250/208.1, 250/206, 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

A vehicular imaging system for capturing an image includes an imaging sensor and an electro-optic filter. The electro-optic filter is operable to attenuate light in response to a voltage applied to said electro-optic filter. The electro-optic filter is positioned along an optic path between the imaging sensor and a scene being captured by the imaging sensor. The imaging system includes a control for applying the voltage to the electro-optic filter. Preferably, the control is operable to selectively apply the voltage to the electro-optic filter. Preferably, the control is operable to selectively apply the voltage to the electro-optic filter in response to an ambient light intensity.

Claims

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

an imaging sensor;

an electro-optic filter which is operable to attenuate light in response to a voltage applied to said electro-optic filter, said electro-optic filter being positioned along an optic path to said imaging sensor; and

a control for applying said voltage to said electro-optic filter.

2. The imaging system of claim 1, wherein said control is operable to selectively apply said voltage to said electro-optic filter.

3. The imaging system of claim 2, wherein said control is operable to selectively apply said voltage to said electro-optic filter in response to an ambient light intensity.

4. The imaging system of claim 1, wherein said electro-optic filter includes an electrochromic medium which attenuates light in response to said voltage being applied to said electro-optic filter.

5. The imaging system of claim 1, wherein said electro-optic filter is operable to attenuate light having a wavelength comprising a near infrared light wavelength in response to said voltage.

6. The imaging system of claim 1, wherein said electro-optic filter is operable to attenuate light having a wavelength within a range of wavelengths in response to said voltage.

7. The imaging system of claim 6, wherein said range of wavelengths includes near infrared light wavelengths.

8. The imaging system of claim 1, wherein said electro-optic filter is operable to substantially attenuate light having a wavelength greater than approximately 750 nanometers in response to said voltage.

9. The imaging system of claim 8, wherein said electro-optic filter is operable to substantially transmit light having a wavelength less than approximately 700 nanometers when said voltage is applied.

10. The imaging system of claim 9, wherein said control is operable to apply said voltage in response to a threshold ambient light level.

11. The imaging system of claim 1, wherein said electro-optic filter is spectrally tuned to filter a predetermined range of light wavelengths in response to said voltage.

12. The imaging system of claim 1, wherein said electro-optic filter comprises at least two electro-optic filters.

13. The imaging system of claim 12, wherein one of said at least two electro-optic filters is operable to attenuate light having a wavelength within a different range of wavelengths than the other of said at least two electro-optic filters in response to said voltage.

14. The imaging system of claim 1, wherein said control is operable to vary said voltage applied to said electro-optic filter.

15. The imaging system of claim 14, wherein said electro-optic filter is operable to vary a transmissivity of light through said electro-optic filter in response to said control varying said voltage applied to said electro-optic filter.

16. The imaging system of claim 1 including an ambient light sensor operable to sense ambient light intensity, said control being operable to adjust said voltage applied to said electro-optic filter in response to said ambient light sensor.

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

18. The imaging system of claim 17, wherein said electrochromic medium comprises at least one of an electrochromic film, an electrochromic solid polymer film, and an electrochromic solution.

19. The imaging system of claim 17, wherein said electrochromic medium is energizable to attenuate light through at least one outer circumferential region of said electro-optic filter while a center region of said electro-optic filter allows light to pass therethrough, said center region being defined by said at least one outer circumferential region.

20. The imaging system of claim 19, wherein said at least one outer circumferential region comprises multiple regions of said electrochromic medium, said control selectively applying said voltage to each said region to attenuate light through that region, said electro-optic filter allowing inwardly positioned regions to pass light therethrough.

21. The imaging system of claim 17, wherein said control is operable to adjust said voltage applied to said electro-optic filter in response to a change in an ambient light intensity.

22. The imaging system of claim 21, wherein said imaging sensor comprises a photon accumulating sensor.

23. The imaging system of claim 22, wherein said imaging sensor comprises a color sensor, said imaging system further including a color filter.