Automatic dimming mirror using semiconductor glare sensor

• US 6,863,405 B2
• Filed: 05/28/2004
• Issued: 03/08/2005
• Est. Priority Date: 01/25/1999
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Fossum, Eric R., Turnbull, Robert R., Stam, Joseph S., Bechtel, Jon H., Nixon, Robert H.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US10/856,675
• Publication Number:
  US 20040218277A1
• Time in Patent Office: 284 Days
• Field of Search: 359604-610, 359601-603, 359264-272, 250/208.1, 250/208.2, 250/209, 250/226, 327/514
• 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
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/46 using a capacitor

Abstract

An automatically dimming mirror includes a dimming element having variable reflectivity, the degree of reflectivity based on a control signal. An ambient light sensor is positioned to receive light from a region generally in front of the vehicle. The ambient light sensor outputs a discrete ambient light signal based on the amount of light incident on the ambient light sensor over an integration period. A glare sensor is positioned to view the scene generally behind the vehicle operator. The glare sensor outputs a discrete glare signal based on the amount of light incident on the glare sensor over an integration period. A dimming logic determines an ambient light level based on the ambient light signal. The glare integration period is determined based on the ambient light level. The glare signal resulting from the glare integration period determines a mirror glare level used to set the dimming element control signal.

Claims

1. A rearview mirror assembly for a vehicle, comprising:

a housing;

an electro-optic mirror element disposed in said housing;

a glare sensor for sensing light levels generally from the rear of the rearview mirror assembly, said glare sensor comprising a light transducer and a lens for redirecting light onto said light transducer; and

a control circuit coupled to said glare sensor and to said electro-optic mirror element for varying a reflectance level of said electro-optic mirror element as a function of the light levels sensed by said glare sensor.

2. The rearview mirror assembly of claim 1, wherein said glare sensor further comprises an encapsulant material disposed over said light transducer, wherein said lens is defined by a surface of said encapsulant material.

3. The rearview mirror assembly of claim 2, wherein said lens is spherical.

4. The rearview mirror assembly of claim 2, wherein said lens is cylindrical.

5. The rearview mirror assembly of claim 2, wherein said lens is aspheric.

6. The rearview mirror assembly of claim 1 and further comprising a lens spaced apart from said glare sensor.

7. The rearview mirror assembly of claim 1, wherein said glare sensor further comprises an infrared filter.

8. The rearview mirror assembly of claim 1, wherein said light transducer is a first light transducer and said glare sensor further comprises a second light transducer.

9. The rearview mirror assembly of claim 8, wherein said glare sensor further comprises a filter for separating infrared radiation from visible radiation, wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer.

10. The rearview mirror assembly of claim 9 and further comprising a shield for shielding said second light transducer from being exposed to light.

11. The rearview mirror assembly of claim 1, wherein said glare sensor is mounted behind said electro-optic mirror element so as to sense light passing through said electro-optic mirror element.

12. The rearview mirror assembly of claim 1, wherein said housing further comprises a bezel, wherein said glare sensor is mounted in said bezel.

13. The rearview mirror assembly of claim 1, wherein said light transducer and another electronic component are integrated within an integrated circuit.

14. The rearview mirror assembly of claim 13, wherein said another electronic component includes a transistor.

15. The rearview mirror assembly of claim 1, wherein said light transducer accumulates charge in proportion to light incident over an integration period.

16. A rearview mirror assembly for a vehicle, comprising:

a housing;

an electro-optic mirror element disposed in said housing;

a light sensor for sensing light levels, said light sensor comprising a light transducer and another electronic component that are both integrated within an integrated circuit; and

a control circuit coupled to said light sensor and to said electro-optic mirror element for varying a reflectance level of said electro-optic mirror element as a function of the light levels sensed by said light sensor.

17. The rearview mirror assembly of claim 16, wherein said light sensor further comprises a lens for redirecting light onto said light transducer.

18. The rearview mirror assembly of claim 16, wherein said light sensor further comprises an encapsulant material disposed over said integrated circuit, wherein a surface of said encapsulant material defines a lens for redirecting light onto said light transducer.

19. The rearview mirror assembly of claim 16 and further comprising a lens spaced apart from said light sensor.

20. The rearview mirror assembly of claim 16, wherein said light sensor further comprises an infrared filter.

21. The rearview mirror assembly of claim 16, wherein said light transducer is a first light transducer and said light sensor further comprises a second light transducer.

22. The rearview mirror assembly of claim 21, wherein said light sensor further comprises a filter for separating infrared radiation from visible radiation, wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer.

23. The rearview mirror assembly of claim 22 and further comprising a shield for shielding said second light transducer from being exposed to light.

24. The rearview mirror assembly of claim 16, wherein said light sensor is mounted behind said electro-optic mirror element so as to sense light passing through said electro-optic mirror element.

25. The rearview mirror assembly of claim 16, wherein said housing further comprises a bezel, wherein said light sensor is mounted in said bezel.

26. The rearview mirror assembly of claim 16, wherein said light transducer accumulates charge in proportion to light incident over an integration period.

27. The rearview mirror assembly of claim 16, wherein said another electronic component is a light-to-pulse circuit for generating pulses in response to light levels sensed by said light transducer.

28. A rearview assembly for using in a vehicle, said rearview assembly comprising:

a housing adapted to be mounted to the vehicle;

a rearview element disposed in the housing for providing an image to the driver of the rearward view from the vehicle; and

a glare sensor device mounted behind said rearview element so as to sense light passing through said rearview element, said glare sensor device comprising;

a light transducer exposed to light, the light transducer operative to accumulate charge; and

a circuit in communication with the exposed light transducer, the circuit operative to output a discrete light signal according to the accumulated exposed light transducer charge.

29. The rearview assembly of claim 28, wherein said light transducer accumulates charge in proportion to light incident over an integration period.

30. The rearview mirror assembly of claim 28, wherein said glare sensor further comprises a lens for redirecting light onto said light transducer.

31. The rearview mirror assembly of claim 30, wherein said glare sensor further comprises an encapsulant material disposed over said light transducer, wherein said lens is defined by a surface of said encapsulant material.

32. The rearview mirror assembly of claim 28 and further comprising a lens spaced apart from said glare sensor.

33. The rearview mirror assembly of claim 28, wherein said glare sensor further comprises an infrared filter.

34. The rearview mirror assembly of claim 28, wherein said light transducer is a first light transducer and said glare sensor further comprises a second light transducer.

35. The rearview mirror assembly of claim 34, wherein said glare sensor further comprises a filter for separating infrared radiation from visible radiation, wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer.

36. The rearview mirror assembly of claim 35 and further comprising a shield for shielding said second light transducer from being exposed to light.

37. The rearview mirror assembly of claim 28, wherein said glare sensor further comprises an integrated circuit, wherein said light transducer and another electronic component are integrated within said integrated circuit.

38. The rearview mirror assembly of claim 37, wherein said another electronic component includes a transistor.

39. The rearview mirror assembly of claim 37, wherein said another electronic component includes said circuit of said glare sensor.