Automatic rearview mirror system for automotive vehicles

• US 4,917,477 A
• Filed: 04/06/1987
• Issued: 04/17/1990
• Est. Priority Date: 04/06/1987
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Byker, Harlan J., Bechtel, Jon H.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/034,913
• Time in Patent Office: 1,107 Days
• Field of Search: 350/357, 350/278, 350/279, 350/281, 350/283
• US Class Current: 359/267
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: G02F 1/153 Constructional details

Abstract

An improved automatic rearview mirror system which is particularly adapted for use with automotive vehicles and which may be utilized as a fully integrated inside/outside rearview mirror system or as an inside or an outside rearview mirror system. The system includes a variable reflectance member the reflectivity of which varies as a function of an electrical signal applied thereto, and the system also includes improved means operable to apply an electrical signal to the variable reflectance member to vary the reflectivity of such member as a function of sensed ambient light and sensed glare causing light.

Claims

1. In an automatic rearview mirror system for automotive vehicles, the combination including an electrochromic variable reflectance member the reflectivity of which varies continuously over a range as a function of at least two electrical signal levels applied thereto, ambient light sensing means effective to sense ambient light and generate a corresponding electrical signal indicative of the ambient light level, glare sensing means effective to sense glare causing light and generate a corresponding electrical signal indicative of the glare causing light level, and means operable to apply an electrical control signal to said variable reflectance member to vary the reflectivity of said reflectance member while maintaining a high quality image during reflectance transition as a function of the sensed ambient light signal and the sensed glare causing light level signal, the total response time of said control signal to changes in the electrical indicative of the glare causing light level being faster than the total response time of said electrochromic reflectance member to said control signal.

2. The combination as set forth in claim 1 wherein the speed of decreasing the reflectance of said reflectance member is faster than the speed of increasing the reflectance of said reflectance member.

3. The combination as set forth in claim 1, said system including means effective to cause said variable reflectance member to exhibit its maximum reflectivity in the event electrical power to the system is interrupted.

4. The combination as set forth in claim 1 characterized in that for a predetermined ambient light condition and for increasingly severe glare, the reflectivity of said reflectance member is reduced to hold the light level reflected to the driver at a substantially constant level through the controllable range of said reflectance member.

5. The combination as set forth in claim 1 characterized in that for a predetermined ambient light condition and for increasingly severe glare, the reflectivity of said reflectance member is altered so as to alter the light level reflected to the driver.

6. The combination as set forth in claim 1 including means preventing significant response to the electrical signal generated by said ambient light sensing means when the light detected by said ambient light sensing means is below a predetermined value.

7. The combination as set forth in claim 1 including means for short circuiting the electrical signal applied to said variable reflectance member when a high reflectance level is required.

8. The combination as set forth in claim 1 including means inhibiting reduction in the reflectance of said variable reflectance member when the vehicle is in reverse gear.

9. The combination as set forth in claim 1 including a second variable reflectance member the reflectance of which varies as a function of an electrical signal applied thereto, and means electrically connecting said variable reflectance members.

10. The combination as set forth in claim 9 one of said variable reflectance members being disposed in the interior of a vehicle, said second variable reflectance member being disposed on the exterior of said vehicle.

11. In an automatic rearview mirror system for automotive vehicles, the combination including an electrochromic mirror having at least a full reflectance mode and a partial reflectance mode and the reflectivity of which varies continuously over a range as a function of time and of an electrical control signal applied thereto, forward facing sensor means effective to detect light forwardly of the vehicle and generate a corresponding forward electrical signal indicative of the forward light level, backward facing sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, means for applying electrical power to said system, and means operable to apply an electrical control signal to said electrochromic mirror to change the reflectance thereof over a continuous range as a function of said forward electrical signal and said rearwafd electrical signal while maintaining a high quality image during reflectance transitions between said modes, the total response time of said control signal to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said electrochromic mirror to said control signal.

12. The combination as set forth in claim 11, said system including means effective to cause said electrochromic mirror to exhibit only its full reflectance mode in the event electrical power to the system is interrupted.

13. The combination as set forth in claim 11, said electrochromic mirror having a time response upon the application of an electrical control signal thereto that is slower than the time response of said rearward electrical signal and effective to average the control signal thereby establishing a range of intermediate reflectance levels.

14. The combination as set forth in claim 11 including means effective to hold said electrochromic mirror in its full reflectance mode when the light detected by said forward facing sensor means exceeds a predetermined value.

15. The combination as set forth in claim 11 including means preventing significant response to the forward electrical signal generated by said forward facing sensor means when the light detected by said forward facing sensor means is below a predetermined value.

16. The combination as set forth in claim 11 including means for short circuiting said electrochromic mirror when a high reflectance condition is required.

17. The combination as set forth in claim 11 including means inhibiting reduction in the reflectivity of said electrochromic mirror from said full reflectance mode when the vehicle is in reverse gear.

18. In an automatic rearview mirror system for automotive vehicles, the combination including an electrochromic mirror having at least a full reflectance mode and a low reflectance mode, the reflectivity of said electrochromic mirror varying as a function of time and of an electrical control signal applied to said mirror, first sensor means effective to detect light forwardly of a vehicle and generate a corresponding forward electrical signal indicative of the forward light level, second sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, means comparing the forward electrical signal and the rearward electrical signal and operable to generate at least two electric control signal for application of an electrical potential to said electrochromic mirror to vary the reflectivity of said mirror as a function of the severity of the glare whereby said electrochromic mirror may be changed between at least a full reflectance mode and a low reflectance mode while maintaining a high quality image during reflectance transitions between said modes as a function of a comparison of the rearward electrical signal and the forward electrical signal, the total response time of said control signals to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said electrochromic mirror to said control signals.

19. The combination as set forth in claim 18, said rearward electrical signal having a time response shorter than the time response of said electrochromic mirror upon the application of varying electrical control signals applied thereto.

20. The combination as set forth in claim 18 including a second electrochromic mirror, and means electrically connecting said electrochromic mirrors whereby said electrochromic mirrors change reflectivity substantially simultaneously.

21. The combination as set forth in claim 20, one of said electrochromic mirrors being disposed in the interior of the vehicle, the other of said electrochromic mirrors being disposed on the exterior of the vehicle.

22. The combination as set forth in claim 21 including means effective to maintain each of said electrochromic mirrors in its full reflectance mode when said vehicle is in reverse gear.

23. The combination as set forth in claim 18 including means for attenuating the light rearwardly of the vehicle, said second sensor being effective to detect the attenuated light.

24. In an automatic rearview mirror system for an automotive vehicle, the combination including a first electrochromic mirror having a full reflectance mode, an intermediate reflectance mode, and a low reflectance mode, the reflectivity of said mirror varying as a function of time and of an electrical control signal applied thereto, first photoelectric sensor means effective to detect light forwardly of the vehicle and generate a corresponding forward electrical signal indicative of the forward light level, second photoelectric sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, means effective to compare said rearward electrical signal and the forward electrical signal and to change the reflectance mode of said mirror as a function of a comparison of said rearward electrical signal with said forward electrical signal as modified by the time response of said mirror upon the application of an electrical control signal thereto, the total response time of said control signal to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said first electrochromic mirror to said control signal.

25. The combination as set forth in claim 24 including a second electrochromic mirror, said first electrochromic mirror being disposed in the interior of the vehicle, said second mirror being disposed on the exterior of the vehicle, and means electrically connecting said mirrors whereby changes in the reflectivity of said mirrors occurs substantially simultaneously.

26. The combination as set forth in claim 24, said system having a power supply including an intermediate reference voltage.

27. The combination as set forth in claim 24, said electrochromic mirror having at least three reflectance modes, said means effective to compare said forward electrical signal and said rearward electrical signal being effective to generate at least three electrical signal levels to change the reflectivity of said mirror to each of said reflectance modes as a function of the value of the rearward light level to establish a full, a low and at least one intermediate reflectance mode.

28. The combination as set forth in claim 25, said second electrochromic mirror having an additional photoelectric sensor means effective to detect light rearwardly of the vehicle and generate an additional rearward electrical signal indicative of the rearward light level impinging thereon.

29. The combination as set forth in claim 24, said second photoelectric sensor means being effective to detect light rearwardly of the vehicle as attenuated by said first electrochromic mirror.

30. In an automatic rearview mirror system for automotive vehicles, the combination including an electrochromic mirror having a full reflectance mode and a partial reflectance mode and the reflectivity of which varies as a function of an electrical control signal applied thereto, forward facing sensor means effective to detect light forwardly of the vehicle and generate a corresponding forward electrical signal indicative of the forward light level, backward facing sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, means having a smoothing time averaging effect on the forward electrical signal and acting on the forward electrical signal to produce a filtered forward electrical signal independent of the rearward electrical signal, and means operable to apply an electrical control signal to said electrochromic mirror to change said electrochromic mirror between said full reflectance mode and said partial reflectance mode as a function of the output of said filtered forward electrical signal, said rearward electrical signal, and the response time of said mirror upon a change in an electrical control signal applied thereto, the total response time of said control signal to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said electrochromic mirror to said control signal.

31. The combination as set forth in claim 30 including means for short circuiting said electrochromic mirror when a high reflectance condition is required.

32. The combination as set forth in claim 30 including means inhibiting reduction in the reflectivity of said electrochromic mirror from said full reflectance mode when the vehicle is in reverse gear.

33. In an automatic rearview mirror system for automotive vehicles, the combination including an electrochromic mirror having a full reflectance mode, at least one intermediate reflectance mode, and a low reflectance mode, the reflectivity of said electrochromic mirror varying as a function of an electrical control signal applied to said mirror, control circuitry including a first sensor means effective to detect light forwardly of a vehicle and generate a corresponding forward electrical signal indicative of the forward light level, said control circuitry including second sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, said control circuitry also including means comparing the forward electrical signal and the rearward electrical signal and operable to apply an electrical potential to said electrochromic mirror to very the reflectivity of said mirror as a function of the forward electrical signal, the rearward electrical signal, and the response time of said mirror upon a change in an electrical control signal applied thereto whereby said electrochromic mirror may be changed between a full reflectance mode, intermediate reflectance modes, and a low reflectance mode as a function of a comparison of the rearward electrical signal, the forward electrical signal, and the response time of said mirror upon a change in an electrical signal applied thereto, the total response time of said control signal to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said electrochromic mirror to said control signal.

34. The combination as set forth in claim 33 including a second electrochromic mirror, said control circuitry including means electrically connecting said electrochromic mirror whereby said electrochromic mirror change reflectivity substantially simultaneously upon a change in an electrical signal applied thereto.

35. The combination as set forth in claim 34, one of said electrochromic mirrors being disposed in the interior of the vehicle, the other of said electrochromic mirrors being disposed on the exterior of the vehicle.

36. The combination as set forth in claim 35 including means effective to maintain each of said electrochromic mirrors in its full reflectance mode when said vehicle is in reverse gear.

37. The combination as set forth in claim 33 including means for attenuating glare producing light rearwardly of the vehicle, said second sensor being effective to detect the attenuated light.

38. In an automatic rearview mirror system for an automotive vehicle, the combination including a first electrochromic mirror having a full reflectance mode, an intermediate reflectance mode, and a low reflectance mode, the reflectivity of said first mirror varying as a function of an electrical control signal applied thereto, first photoelectric sensor means effective to detect light forwardly of the vehicle and generate a corresponding forward electrical signal indicative of the forward light level, second photoelectrical sensor means effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, forward sensor filtering means characterized by having a first time response and having a smoothing time averaging effect on the forward electrical signal and acting on the forward electrical signal to produce a filtered forward electrical signal independent of the rearward electrical signal, and means effective to compare said rearward electrical signal and the filtered forward electrical signal and to change the reflectance mode of said first electrochromic mirror as a function of a comparison of said filtered forward electrical signal and said rearward electrical signal and the response time of said first mirror upon a change in an electrical control signal applied thereto, the total response time of said control signal to changes in the electrical signal indicative of the rearward light level being faster than the total response time of said first electrochromic mirror to said control signal.

39. The combination as set forth in claim 38 including a second electrochromic mirror, said first electrochromic mirror being disposed in the interior of the vehicle, said second mirror being disposed on the exterior of the vehicle, and means electrically connecting said mirrors whereby changes in the reflectivity of said mirrors occur substantially simultaneously.

40. The combination as set forth in claim 39, said system having a power supply including an intermediate reference voltage.

41. The combination as set forth in claim 38, said first electrochromic mirror having at least three reflectance modes, said means effective to compare said filtered forward electrical signal and said rearward electrical signal being effective to change the reflectivity of said first electrochromic mirror to each of said reflectance modes.

42. The combination as set forth in claim 39, said second electrochromic mirror having an additional photoelectrical sensor means effective to detect light rearwardly of the vehicle and generate an additional rearward electrical signal indicative of the rearward light level impinging thereon.

43. The combination as set forth in claim 38, said second photoelectric sensor means being effective to detect light rearwardly of the vehicle as attenuated by said first electrochromic mirror.

44. In an automatic rearview mirror system for automotive vehicles, the combination including a first electrochromic mirror having at least a full reflectance mode and a partial reflectance mode and the reflectivity of which varies a function of an electrical signal applied thereto, said first electrochromic mirror being disposed in the interior of a vehicle, a second electrochromic mirror having at least a full reflectance mode and a partial reflectance mode and the reflectivity of which also varies as a function of an electrical signal applied thereto, said second electrochromic mirror being disposed on the exterior of said vehicle, first photoelectric sensor means carried by said first electrochromic mirror and effective to detect light forwardly of the vehicle and generate a corresponding forward electrical signal indicative of the forward light level, second photoelectric sensor means carried by said first electrochromic mirror and effective to detect light rearwardly of the vehicle and generate a corresponding rearward electrical signal indicative of the rearward light level, and means operable to apply an electrical control signal to each of said first and second electrochromic mirrors to change the reflectivity of each of said first and second electrochromic mirrors as a function of said forward electrical signal and said rearward electrical signal.