Individual mirror control system

• US 6,595,650 B2
• Filed: 05/02/2002
• Issued: 07/22/2003
• Est. Priority Date: 09/16/1997
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Turnbull, Robert R., Knapp, Robert C., Vawter, Roy E.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US10/137,603
• Publication Number:
  US 20020131177A1
• Time in Patent Office: 446 Days
• Field of Search: 359/604, 359/605, 359/265, 359/266, 359/267, 359/270, 359/273, 359/601, 359/602, 359/608
• 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

Abstract

A control system for a plurality of electrochromic elements, for example, used in automobiles, to control the glare of the IEC elements used as a rearview mirror (20) as well as the OEC elements (24, 26) used as sideview mirrors (24, 26). The IEC element and each of the OEC elements is provided with an individual drive circuit (21, 22). The drive circuits for the OEC'"'"'s elements may be customized to account for various factors such as the type of curvature as well as the size and shape. Since individual drive circuitry is provided for the IEC elements and each of the OEC elements, the reflectance of each of the electrochromic elements (20, 24, 26) can be relatively accurately controlled by way of glare signal from inside the automobile.

Claims

1. A control system for controlling the reflectivity of an inside rearview mirror and at least one outside rearview mirror of a vehicle, said control system comprising:

a light sensor for sensing the level of light coming from the rear of the vehicle; and

a control circuit electrically coupled to said light sensor and to the inside rearview mirror and the at least one outside rearview mirror, said control circuit adjusts the reflectivity of the rearview mirrors responsive to the light level sensed by said light sensor, said control circuit generates separate drive signals for adjusting the reflectivity of the inside rearview mirror and the reflectivity of the at least one outside rearview mirror.

2. The control system of claim 1, wherein said drive signals are PWM signals having different pulse widths.

3. The control system of claim 1, wherein said control circuit adjusts the reflectivity of the inside rearview mirror to be greater than that of the at least one outside rearview mirror.

4. The control system of claim 1, wherein said control circuit includes separate drive circuits for the inside mirror and the at least one outside mirror that respectively generate the separate drive signals applied to the inside rearview mirror and the at least one outside rearview mirror.

5. The control system of claim 1, wherein said control circuit includes a controller coupled to said light sensor and individual drive circuits for each rearview mirror, said individual drive circuits are coupled to said controller.

6. The control system of claim 5, wherein each of the rearview mirrors includes a housing and wherein said individual drive circuits are mounted in the respective housings.

7. The control system of claim 6, wherein said controller is mounted in the housing of the inside rearview mirror.

8. The control system of claim 6, wherein said light sensor is mounted in the housing of the inside rearview mirror.

9. The control system of claim 1, wherein said control circuit controls the reflectivity of the rearview mirrors such that the reflected light at a predetermined reference point is relatively constant.

10. The control system of claim 1, wherein said control circuit controls the reflectivity of each of the rearview mirrors based upon a reflectance curve associated with each rearview mirror, the reflectance curve establishes a relationship between sensed light levels and desired reflectivity levels, wherein the reflectance curve for the inside rearview mirror has at least one different characteristic than the reflectance curve of the at least one outside rearview mirror.

11. The control system of claim 1, wherein each of the rearview mirrors is an electrochromic mirror.

12. The control system of claim 1, wherein said control circuit varies the relation between voltage levels applied across the inside rearview mirror and the at least one outside rearview mirror.

13. The control system of claim 1, wherein said control circuit controls a relationship of the reflectivity of the inside rearview mirror and the at least one outside rearview mirror as a function of the light transmissivity of the rear window of the vehicle.

14. A control system for controlling the reflectivity of an inside rearview mirror and at least one outside rearview mirror of a vehicle, said control system comprising:

a light sensor for sensing the level of light coming from the rear of the vehicle; and

a control circuit electrically coupled to said light sensor and to the inside rearview mirror and the at least one outside rearview mirror, said control circuit adjusts the reflectivity of the rearview mirrors responsive to the light level sensed by said light sensor, said control circuit adjusts the reflectivity of the inside rearview mirror by adjusting the voltage level applied across the inside rearview mirror and adjusts the reflectivity of the at least one outside rearview mirror by adjusting the voltage level applied across the at least one outside rearview mirror, wherein said control circuit separately adjusts the voltage levels applied across the rearview mirrors.

15. The control system of claim 14, wherein said control circuit adjusts the reflectivity of the inside rearview mirror to be greater than that of the at least one outside rearview mirror.

16. The control system of claim 14, wherein said control circuit includes separate drive circuits for the inside rearview mirror and the at least one outside rearview mirror.

17. The control system of claim 14, wherein said control circuit includes a controller coupled to said light sensor and individual drive circuits for each rearview mirror, said individual drive circuits are coupled to said controller.

18. The control system of claim 17, wherein each of said rearview mirrors includes a housing and wherein said individual drive circuits are mounted in the respective housings.

19. The control system of claim 18, wherein said controller is mounted in the housing of the inside rearview mirror.

20. The control system of claim 18, wherein said light sensor is mounted to the housing of the inside rearview mirror.

21. The control system of claim 14, wherein said control circuit controls the reflectivity of the rearview mirrors such that the reflected light at a predetermined reference point is relatively constant.

22. The control system of claim 14, wherein said control circuit controls the reflectivity of each of the rearview mirrors based upon a reflectance curve associated with each rearview mirror, the reflectance curve establishes a relationship between sensed light levels and desired reflectivity levels, wherein the reflectance curve for the inside rearview mirror has at least one different characteristic than the reflectance curve of the at least one outside rearview mirror.

23. The control system of claim 22, wherein said different characteristic is the slope.

24. The control system of claim 22, wherein said different characteristic is the offset.

25. The control system of claim 14, wherein each of the rearview mirrors is an electrochromic mirror.

26. The control system of claim 14, wherein said control circuit adjusts the voltage levels applied across the rearview mirrors by generating first and second PWM drive signals.

27. The control system of claim 14, wherein said control circuit varies the relation between voltage levels applied across the inside rearview mirror and the at least one outside rearview mirror.

28. The control system of claim 14, wherein said control circuit controls a relationship of the reflectivity of the inside rearview mirror and the at least one outside rearview mirror as a function of the light transmissivity of the rear window of the vehicle.

29. A rear vision system for a vehicle, the vehicle having a rear window made of privacy glass, the rear vision system comprising:

an outside rearview mirror for mounting to the outside of the vehicle, said outside mirror having a reflectivity that varies in response to an outside mirror drive signal;

an inside rearview mirror for mounting to the inside of the vehicle to reflect light entering through the privacy glass of the rear window towards the eyes of the driver, said inside mirror having a reflectivity that varies in response to an inside mirror drive signal;

a light sensor for sensing the level of light coming from the rear of the vehicle; and

a control circuit electrically coupled to said light sensor and to said inside and outside rearview mirrors, said control circuit adjusts the reflectivity of said rearview mirrors responsive to the light level sensed by said light sensor, said control circuit generates the outside mirror drive signal for adjusting the reflectivity of the outside rearview mirror, the inside mirror drive signal representing a different reflectivity level than the outside mirror drive signal.

30. The rear vision system of claim 29 and further including a second outside rearview mirror for mounting to the exterior of the vehicle, said second outside rearview mirror having a reflectivity that varies in response to the outside mirror drive signal.

31. The rear vision system of claim 29 and further including a second outside rearview mirror for mounting to the exterior of the vehicle, said second outside mirror having a reflectivity that varies in response to a second outside mirror drive signal that is generated by said control circuit.

32. The rear vision system of claim 29, wherein the vehicle includes a rear window made of privacy glass, and wherein said light sensor is mounted inside the vehicle such that light received from behind the vehicle projects through the privacy glass of the rear window before reaching said light sensor.

33. The rear vision system of claim 32, wherein said light sensor is mounted in a housing of said inside rearview mirror.

34. The rear vision system of claim 29, wherein said control circuit includes a controller coupled to said light sensor and individual drive circuits for each rearview mirror, said individual drive circuits are coupled to said controller.

35. The rear vision system of claim 34, wherein each of said rearview mirrors includes a housing and wherein said individual drive circuits are mounted in the respective housings.

36. The rear vision system of claim 35, wherein said controller is mounted in the housing of said inside rearview mirror.

37. The rear vision system of claim 29, wherein said control subsystem controls the reflectivity of said rearview mirrors such that the reflected light at a predetermined reference point is relatively constant.

38. The rear vision system of claim 29, wherein said control subsystem controls the reflectivity of each of said rearview mirrors based upon a reflectance curve associated with each rearview mirror, the reflectance curve establishes a relationship between sensed light levels and desired reflectivity levels, wherein the reflectance curve for said inside rearview mirror has at least one different characteristic than the reflectance curve of said outside rearview mirror.

39. The rear vision system of claim 29, wherein each of said rearview mirrors is an electrochromic mirror.

40. A control system for controlling the reflectivity of an inside rearview mirror and at least one outside rearview mirror of a vehicle, said control system comprising:

a light sensor for sensing the level of light coming from the rear of the vehicle; and

a control circuit electrically coupled to said light sensor and to the inside rearview mirror and the at least one outside rearview mirror, said control circuit adjusts the reflectivity of the rearview mirrors responsive to the light level sensed by said light sensor, said control circuit generates a first PWM drive signal for adjusting the reflectivity of the at least one outside rearview mirror, wherein the first and second PWM drive signals have different pulse widths.

41. The control system of claim 40, wherein said control circuit generates a third PWM drive signal for adjusting the reflectivity of a second outside rearview mirror, the third PWM drive signal having a different pulse width than the first and second PWM drive signals.

42. The control system of claim 40, wherein each of the rearview mirrors is an electrochromic mirror.

43. The control system of claim 40, wherein said control circuit controls the reflectivity of the inside rearview mirror differently than that of the at least one outside rearview mirror to compensate for the privacy glass of the rear window of the vehicle.