Vehicle rearview mirror system

• US 7,906,756 B2
• Filed: 04/23/2010
• Issued: 03/15/2011
• Est. Priority Date: 05/03/2002
• Status: Active Grant

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Drummond, John P., Schofield, Kenneth
• Primary Examiner(s): Pyo; Kevin
• Application Number:
  US12/766,150
• Publication Number:
  US 20100207013A1
• Time in Patent Office: 326 Days
• Field of Search: 250/221, 250/208.1, 250/216, 250/205, 250/214.R, 250/214.AL, 250/214.B, 250/214.C, 359/601, 359/602, 359/604, 359/605, 359/608, 359/609, 362/494, 362/540
• US Class Current: 250/214.0AL
• 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 1/26 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G02B 27/01 Head-up displays

Abstract

A vehicle rearview mirror system includes an electrochromic transflective reflective element, an ambient light sensor operable to sense ambient light, a glare light sensor operable to sense glare light and a control circuit that is responsive to light detection by at least one of the ambient and glare light sensors and that establishes a reflectance level of the reflective element. The mirror system includes a display element disposed behind the transflective reflective element and operable to display information through the mirror reflector of the reflective element and viewable through the mirror reflector by a driver of the vehicle when the display element is displaying information, and substantially non-viewable by the driver of the vehicle when the display element is not displaying information. The system includes a display intensity control for adjusting display intensity responsive to light detection by at least one of the glare light sensor and ambient light sensor.

Claims

1. A rearview mirror system for a vehicle, said rearview mirror system comprising:

an interior rearview mirror assembly having a transflective electrochromic reflective element, said reflective element having a front surface and a rear surface, said front surface being closer to the driver of a vehicle than said rear surface when said mirror assembly is mounted in a vehicle equipped with said rearview mirror system;

wherein said transflective reflective element comprises a mirror reflector that partially reflects light incident thereon and that partially transmits light incident thereon;

wherein said transflective reflective element is at least about 15 percent transmitting to visible light incident from rearward of said rear surface of said reflective element;

an ambient light sensor operable to sense ambient light;

a glare light sensor operable to sense light incident at or near said reflective element;

wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit;

wherein said glare light sensor converts incident light to a signal processed by a microprocessor;

wherein said ambient light sensor converts incident light to a signal processed by said microprocessor;

a control circuit operable to establish a reflectance level of said reflective element, wherein said control circuit is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a display element disposed behind said transflective electrochromic reflective element and operable to display information through said mirror reflector of said transflective electrochromic reflective element and viewable through said mirror reflector of said transflective electrochromic reflective element by a driver of the vehicle when said display element is displaying information, and substantially non-viewable by the driver of the vehicle when said display element is not displaying information;

wherein said display element comprises a TFT liquid crystal display video screen backlit by at least one white light light emitting diode;

a display intensity control for adjusting display intensity of said display element, said display intensity control adjusting display intensity responsive to a light detection by at least one of said glare light sensor and said ambient light sensor, and wherein display intensity is adjusted responsive to at least a light level detected by at least one of said ambient light sensor and said glare light sensor; and

wherein said rearview mirror system further comprises temperature compensation of at least one of said glare light sensor and said ambient light sensor.

2. The rearview mirror system of claim 1, wherein said transflective reflective element is at least about 60 percent reflective to visible light incident from its front.

3. The rearview minor system of claim 1, wherein said associated circuitry of said ambient light sensor comprises a current-to-frequency converter and wherein said associated circuitry of said glare light sensor comprises a current-to-frequency converter.

4. The rearview mirror system of claim 1, wherein said temperature compensation is responsive to a reference sensor that is not exposed to light.

5. The rearview mirror system of claim 1, wherein said temperature compensation is responsive to a temperature sensor.

6. The rearview mirror system of claim 1, wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit.

7. The rearview mirror system of claim 1, wherein said control circuit comprises a charge accumulation device, a comparison function and a controller, said comparison function comparing an output of said charge accumulation device with a reference, said controller selectively connecting said glare sensor and said ambient light sensor with said charge accumulation device.

8. The rearview mirror system of claim 7, wherein said control circuit at least one of (i) alternates connecting said glare light sensor and said ambient light sensor with said charge accumulation device, and (ii) comprises compensation to adapt said control circuit to changes in light levels sensed by said glare and ambient light sensors and wherein said compensation comprises a plurality of voltage reference levels and said control circuit selectively compares an output of said charge accumulation device with one of said voltage reference levels.

9. The rearview mirror system of claim 7, wherein said control circuit comprises a drive function that produces a drive signal that is applied to said reflective element, said drive function comprising a switching device, said circuit operating said switching device at a particular duty cycle to establish the reflectance level of said reflective element.

10. The rearview mirror system of claim 1, wherein said control circuit establishes a reflectance level of said reflective element responsive to a ratio of a glare light value to an ambient light value.

11. The rearview mirror system of claim 10, wherein said ratio of glare light value to ambient light value is from about 0.01 to at least about 100.

12. The rearview mirror system of claim 10, wherein said control circuit establishes said reflectance level within a relatively linear value of said ratio of glare light value to ambient light value.

13. The rearview mirror system of claim 1, wherein said display intensity control establishes a display intensity regardless of a lighting level of a background field.

14. The rearview mirror system of claim 13, wherein said display intensity control establishes a display intensity regardless of the darkness of the background field.

15. The rearview mirror system of claim 1, wherein said display intensity control controls display intensity in accordance with the equation:

I=Fn(^(ME*GV)/_AV);

where I is the display intensity, ME is a modulating effect, GV is a glare light value, and AV is an ambient light value, and wherein display intensity as calculated by said equation has a value of one when the value of (ME*GV)/AV is less than one.

16. A rearview mirror system for a vehicle, said rearview mirror system comprising:

an interior rearview mirror assembly having a transflective electrochromic reflective element, said reflective element having a front surface and a rear surface, said front surface being closer to the driver of a vehicle than said rear surface when said mirror assembly is mounted in a vehicle equipped with said rearview mirror system;

wherein said transflective reflective element comprises a mirror reflector that partially reflects light incident thereon and that partially transmits light incident thereon;

wherein said transflective reflective element is at least about 15 percent transmitting to visible light incident from rearward of said rear surface of said reflective element;

an ambient light sensor operable to sense ambient light;

a glare light sensor operable to sense light incident at or near said reflective element;

wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit;

wherein said glare light sensor converts incident light to a signal processed by a microprocessor;

wherein said ambient light sensor converts incident light to a signal processed by said microprocessor;

a control circuit operable to establish a reflectance level of said reflective element, wherein said control circuit is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a display element disposed behind said transflective electrochromic reflective element and operable to display information through said mirror reflector of said transflective electrochromic reflective element and viewable through said mirror reflector of said transflective electrochromic reflective element by a driver of the vehicle when said display element is displaying information, and substantially non-viewable by the driver of the vehicle when said display element is not displaying information;

wherein said display element comprises a TFT liquid crystal display video screen backlit by at least one white light light emitting diode;

a display intensity control for adjusting display intensity of said display element, said display intensity control adjusting display intensity responsive to a light detection by at least one of said glare light sensor and said ambient light sensor, and wherein display intensity is adjusted responsive to at least a light level detected by at least one of said ambient light sensor and said glare light sensor;

wherein said rearview mirror system further comprises temperature compensation of at least one of said glare light sensor and said ambient light sensor, and wherein said temperature compensation is responsive to a reference sensor that is not exposed to light; and

wherein said control circuit establishes a reflectance level of said reflective element responsive to a ratio of a glare light value to an ambient light value, and wherein said ratio of glare light value to ambient light value is from about 0.01 to at least about 100.

17. The rearview mirror system of claim 16, wherein said control circuit establishes said reflectance level within a relatively linear value of said ratio of glare light value to ambient light value.

18. A rearview mirror system for a vehicle, said rearview mirror system comprising:

an interior rearview mirror assembly having a transflective electrochromic reflective element, said reflective element having a front surface and a rear surface, said front surface being closer to the driver of a vehicle than said rear surface when said mirror assembly is mounted in a vehicle equipped with said rearview mirror system;

wherein said transflective reflective element comprises a mirror reflector that partially reflects light incident thereon and that partially transmits light incident thereon;

wherein said transflective reflective element is at least about 15 percent transmitting to visible light incident from rearward of said rear surface of said reflective element;

an ambient light sensor operable to sense ambient light;

a glare light sensor operable to sense light incident at or near said reflective element;

wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as an integrated circuit;

wherein said glare light sensor converts incident light to a signal processed by a microprocessor;

wherein said ambient light sensor converts incident light to a signal processed by said microprocessor;

a control circuit operable to establish a reflectance level of said reflective element, wherein said control circuit is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a display element disposed behind said transflective electrochromic reflective element and operable to display information through said mirror reflector of said transflective electrochromic reflective element and viewable through said mirror reflector of said transflective electrochromic reflective element by a driver of the vehicle when said display element is displaying information, and substantially non-viewable by the driver of the vehicle when said display element is not displaying information;

wherein said display element comprises a TFT liquid crystal display video screen backlit by at least one white light light emitting diode;

a display intensity control for adjusting display intensity of said display element, said display intensity control adjusting display intensity responsive to a light detection by at least one of said glare light sensor and said ambient light sensor, and wherein display intensity is adjusted responsive to at least a light level detected by at least one of said ambient light sensor and said glare light sensor; and

wherein said display intensity control establishes a display intensity regardless of the darkness of the background field.

19. The rearview mirror system of claim 18, wherein said control circuit establishes a reflectance level of said reflective element responsive to a ratio of a glare light value to an ambient light value, and wherein said ratio of glare light value to ambient light value is from about 0.01 to at least about 100.

20. The rearview mirror system of claim 19, wherein said control circuit establishes said reflectance level within a relatively linear value of said ratio of glare light value to ambient light value.

21. The rearview mirror system of claim 18, comprising temperature compensation of at least one of said glare light sensor and said ambient light sensor, wherein said temperature compensation is responsive to a reference sensor that is not exposed to light.