Light sensor

• US 20040222359A1
• Filed: 05/18/2004
• Published: 11/11/2004
• Est. Priority Date: 01/25/1999
• Status: Active Grant

• Current Assignee: Eric R. Fossum, Jon H. Bechtel, Robert H. Nixon
• Original Assignee: Eric R. Fossum, Jon H. Bechtel, Robert H. Nixon
• Inventors: Fossum, Eric R., Bechtel, Jon H., Nixon, Robert H.
• Granted Patent: US 7,087,878 B2
• Time in Patent Office: Days
• US Class Current: 250/214C
• 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 1/0488 with spectral filtering
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 31/101 Devices sensitive to infrared, visible or ultraviolet radiation
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

Light sensors having a wide dynamic range are used in a variety of applications. A wide dynamic range light sensor includes an exposed photodiode light transducer accumulating charge in proportion to light incident over an integration period. Sensor logic determines a light integration period prior to the beginning of integration and the charge is reset. Charge accumulated by the exposed light transducer over the light integration period is measured and a pulse having a width based on the accumulated charge is determined.

Claims

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

a housing for mounting to the vehicle;

a rearview element disposed in said housing for providing an image of a scene to the rear of the vehicle, the brightness of the image being variable;

a light sensor comprising;

a support member,

a first light transducer mounted on said support member,

a second light transducer mounted on said support member, and

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; and

a control circuit for varying the brightness of the image in response to an output of said light sensor.

2. The rearview assembly of claim 1, wherein said support member is a lead frame.

3. The rearview assembly of claim 1, wherein said first and second light transducers are provided in a common integrated circuit.

4. The rearview assembly of claim 1 and further comprising a light-to-pulse circuit.

5. The rearview assembly of claim 1, wherein said light-to-pulse circuit and said light transducers are provided in a common integrated circuit.

6. The rearview assembly of claim 1 and further comprising a lens for focusing light onto said light transducers.

7. The rearview assembly of claim 1 and further comprising a shield for shielding said second light transducer from being exposed to light.

8. The rearview assembly of claim 1 and further comprising a sensor logic circuit for subtracting the output of one of said light transducers from the other of said light transducers.

9. The rearview assembly of claim 1, wherein said rearview element is a mirror element.

10. The rearview assembly of claim 9, wherein said mirror element is an electrochromic mirror element.

11. The rearview assembly of claim 1, wherein said rearview element comprises a reflective surface.

12. The rearview assembly of claim 1, wherein said filter prevents said first light transducer from being exposed to infrared radiation.

13. The rearview assembly of claim 12, wherein said filter prevents both said first and second light transducers from being exposed to infrared radiation.

14. A rearview assembly for a vehicle, said rearview assembly comprising:

a housing for mounting to the vehicle;

a rearview element disposed in said housing for providing an image of a scene to the rear of the vehicle, the brightness of the image being variable;

a light sensor comprising;

a support member,

a first light transducer mounted on said support member, and

a second light transducer mounted on said support member,

wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer; and

a control circuit for varying the brightness of the image in response to an output of said light sensor.

15. The rearview assembly of claim 14, wherein said support member is a lead frame.

16. The rearview assembly of claim 14, wherein said first and second light transducers are provided in a common integrated circuit.

17. The rearview assembly of claim 14 and further comprising a light-to-pulse circuit.

18. The rearview assembly of claim 14, wherein said light-to-pulse circuit and said light transducers are provided in a common integrated circuit.

19. The rearview assembly of claim 14 and further comprising a lens for focusing light onto said light transducers.

20. The rearview assembly of claim 14 and further comprising a shield for shielding said second light transducer from being exposed to light.

21. The rearview assembly of claim 14 and further comprising a sensor logic circuit for subtracting the output of one of said light transducers from the other of said light transducers.

22. A rearview mirror assembly for a vehicle, said rearview mirror assembly comprising:

a housing for mounting to the vehicle;

a rearview mirror element disposed in said housing for providing an image of a scene to the rear of the vehicle, the reflectivity of said rearview mirror element being variable;

a light sensor comprising;

a support member,

a first light transducer mounted on said support member,

a second light transducer mounted on said support member,

a filter for separating infrared radiation from visible radiation, and

a sensor logic circuit for subtracting the output of one of said light transducers from the other of said light transducers,

wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer; and

a control circuit for varying the reflectivity of said rearview mirror element in response to an output of said light sensor.

23. The rearview mirror assembly of claim 22, wherein said support member is a lead frame.

24. The rearview mirror assembly of claim 22, wherein said first and second light transducers are provided in a common integrated circuit.

25. The rearview mirror assembly of claim 22 and further comprising a light-to-pulse circuit.

26. The rearview mirror assembly of claim 22, wherein said light-to-pulse circuit and said light transducers are provided in a common integrated circuit.

27. The rearview mirror assembly of claim 22 and further comprising a lens for focusing light onto said light transducers.

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

29. A light sensor comprising:

a support member; and

an integrated circuit mounted on said support member, said integrated circuit consisting essentially of;

a first light transducer mounted on said support member,

a second light transducer mounted on said support member, and

non-photo-responsive circuitry for interfacing with said light transducers,

wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer.

30. The light sensor of claim 29, wherein said support member is a lead frame comprising at least two leads.

31. The light sensor of claim 30 and further comprising an encapsulant for encapsulating said integrated circuit and for covering a portion of said leads.

32. The light sensor of claim 29 and further comprising a filter for separating infrared radiation from visible radiation,

33. The light sensor of claim 29, wherein said non-photo-responsive circuitry includes a light-to-pulse circuit.

34. The light sensor of claim 29 and further comprising a lens for focusing light onto said light transducers.

35. A light sensor comprising:

a support member; and

an integrated circuit mounted on said support member, said integrated circuit consisting essentially of;

a number of light transducers mounted on said support member, wherein the number of light transducers is between two and six, said light transducers including a first light transducer and a second light transducer, and

non-photo-responsive circuitry for interfacing with said light transducers,

wherein said second light transducer is not exposed to the same optical spectrum as said first light transducer.

36. The light sensor of claim 35, wherein said support member is a lead frame comprising at least two leads.

37. The light sensor of claim 36 and further comprising an encapsulant for encapsulating said integrated circuit and for covering a portion of said leads.

38. The light sensor of claim 35 and further comprising a filter for separating infrared radiation from visible radiation.

39. The light sensor of claim 35, wherein said non-photo-responsive circuitry includes a light-to-pulse circuit.

40. The light sensor of claim 35 and further comprising a lens for focusing light onto said light transducers.

41. The light sensor of claim 35 and further comprising a shield for shielding said second light transducer from being exposed to light.

42. The light sensor of claim 35, wherein said non-photo-responsive circuitry includes a sensor logic circuit for subtracting the output of one of said light transducers from the other of said light transducers.

43. The light sensor of claim 35 and further comprising a shield for shielding said second light transducer from being exposed to light.

44. The light sensor of claim 35, wherein said non-photo-responsive circuitry includes a sensor logic circuit for subtracting the output of one of said light transducers from the other of said light transducers.