VEHICLE REARVIEW MIRROR SYSTEM

• US 20110147570A1
• Filed: 03/01/2011
• Published: 06/23/2011
• 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
• Granted Patent: US 8,106,347 B2
• Time in Patent Office: Days
• US Class Current: 250/214.AL
• 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 vehicular interior rearview mirror system includes an interior rearview mirror assembly, which includes an ambient light sensor operable to sense ambient light and a glare light sensor operable to sense glare light. A control is operable to establish a reflectance level of a transflective electrochromic reflective element of the mirror assembly and is responsive to light detection by the ambient light sensor and/or the glare light sensor. A backlit video screen is disposed behind the reflective element and is operable to display information through the mirror reflector of the reflective element. A display intensity control adjusts display intensity responsive to a light detection by the glare light sensor and/or the ambient light sensor and as a function of a ratio of a glare light value sensed by the glare light sensor to an ambient light value sensed by the ambient light sensor.

Claims

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

an interior rearview mirror assembly having a transflective electrochromic reflective element, said transflective electrochromic reflective element comprising a front substrate having a first surface and a second surface opposite said first surface and said transflective electrochromic reflective element comprising a rear substrate having a third surface and a fourth surface opposite said third surface, wherein said third surface of said rear substrate is closer to the driver of a vehicle than said fourth surface of said rear substrate when said interior rearview mirror assembly is mounted in a vehicle equipped with said interior rearview mirror system;

wherein said transflective electrochromic reflective element comprises a mirror reflector that partially reflects light and that partially transmits light, wherein said mirror reflector is disposed at said third surface of said rear substrate and wherein a transparent electrically conductive layer is disposed at said second surface of said front substrate;

wherein said transflective electrochromic reflective element comprises an electrochromic medium disposed between said second surface of said front substrate and said third surface of said rear substrate;

wherein said interior rearview mirror assembly comprises an ambient light sensor operable to sense ambient light;

wherein said interior rearview mirror assembly comprises a glare light sensor operable to sense glare light;

wherein said interior rearview mirror assembly comprises a control operable to establish a reflectance level of said transflective electrochromic reflective element, wherein said control is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a backlit video screen 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 backlit video screen is displaying information, and substantially non-viewable by the driver of the vehicle when said backlit video screen is not displaying information;

a display intensity control for adjusting display intensity of said backlit video screen, 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 of said backlit video screen is adjusted as a function of a ratio of a glare light value sensed by said glare light sensor to an ambient light value sensed by said ambient light sensor, and wherein said function comprises at least one of (a) a step function, (b) linear function, (c) a logarithmic function and (d) a continuous function.

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

3. The interior rearview mirror system of claim 2, wherein said control establishes said reflectance level within a relatively linear value of said ratio of glare light value to ambient light value.

4. The interior rearview mirror system of claim 1, wherein said function is influenced by a modulating effect of said transflective electrochromic reflective element.

5. The interior rearview mirror system of claim 4, 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 said modulating effect, GV is the glare light value, and AV is the 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.

6. The interior rearview mirror system of claim 5, wherein said modulation effect ME is based on a double pass of light through said electrochromic medium.

7. The interior rearview mirror system of claim 6, wherein display intensity may be corrected to a corrected intensity value I_(c), in accordance with the following equation:

I_(c)=I*ME<sup>−

1/2</sup>.

8. The interior rearview mirror system of claim 1, 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.

9. The interior rearview mirror system of claim 8, 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.

10. The interior 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.

11. The interior rearview mirror system of claim 1, wherein said control 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.

12. The interior rearview mirror system of claim 11, wherein said control alternates connecting said glare light sensor and said ambient light sensor with said charge accumulation device.

13. The interior rearview mirror system of claim 11, wherein said control comprises compensation to adapt said control 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 selectively compares an output of said charge accumulation device with one of said voltage reference levels.

14. The interior rearview mirror system of claim 11, wherein said control comprises a drive function that produces a drive signal that is applied to said reflective element, said drive function comprising a switching device, said control operating said switching device at a particular duty cycle to establish the reflectance level of said reflective element.

15. The interior rearview mirror system of claim 1, 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.

16. An interior rearview mirror system for a vehicle, said interior rearview mirror system comprising;

an interior rearview mirror assembly having a transflective electrochromic reflective element, said transflective electrochromic reflective element comprising a front substrate having a first surface and a second surface opposite said first surface and said transflective electrochromic reflective element comprising a rear substrate having a third surface and a fourth surface opposite said third surface, wherein said third surface of said rear substrate is closer to the driver of a vehicle than said fourth surface of said rear substrate when said interior rearview mirror assembly is mounted in a vehicle equipped with said interior rearview mirror system;

wherein said transflective electrochromic reflective element comprises a mirror reflector that partially reflects light and that partially transmits light, wherein said mirror reflector is disposed at said third surface of said rear substrate and wherein a transparent electrically conductive layer is disposed at said second surface of said front substrate;

wherein said transflective electrochromic reflective element comprises an electrochromic medium disposed between said second surface of said front substrate and said third surface of said rear substrate;

wherein said interior rearview mirror assembly comprises an ambient light sensor operable to sense ambient light and wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit;

wherein said interior rearview mirror assembly comprises a glare light sensor operable to sense glare light and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit;

wherein said interior rearview mirror assembly comprises a control operable to establish a reflectance level of said transflective electrochromic reflective element, wherein said control is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a backlit video screen 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 backlit video screen is displaying information, and substantially non-viewable by the driver of the vehicle when said backlit video screen is not displaying information;

a display intensity control for adjusting display intensity of said backlit video screen, 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 of said backlit video screen is adjusted as a function of a ratio of a glare light value sensed by said glare light sensor to an ambient light value sensed by said ambient light sensor, and wherein said function comprises a step function.

17. The interior rearview mirror system of claim 16, wherein said function is influenced by a modulating effect of said transflective electrochromic reflective element.

18. The interior rearview mirror system of claim 17, 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 said modulating effect, GV is the glare light value, and AV is the 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.

19. The interior rearview mirror system of claim 18, wherein said modulation effect ME is based on a double pass of light through said electrochromic medium.

20. The interior rearview mirror system of claim 19, wherein display intensity may be corrected to a corrected intensity value I_(c), in accordance with the following equation:

I_(c)=I*ME<sup>−

1/2</sup>.

21. An interior rearview mirror system for a vehicle, said interior rearview mirror system comprising:

an interior rearview mirror assembly having a transflective electrochromic reflective element, said transflective electrochromic reflective element comprising a front substrate having a first surface and a second surface opposite said first surface and said transflective electrochromic reflective element comprising a rear substrate having a third surface and a fourth surface opposite said third surface, wherein said third surface of said rear substrate is closer to the driver of a vehicle than said fourth surface of said rear substrate when said interior rearview mirror assembly is mounted in a vehicle equipped with said interior rearview mirror system;

wherein said transflective electrochromic reflective element comprises a mirror reflector that partially reflects light and that partially transmits light, wherein said mirror reflector is disposed at one of (a) said third surface of said rear substrate and (b) said fourth surface of said rear substrate, and wherein a transparent electrically conductive layer is disposed at said second surface of said front substrate;

wherein said transflective electrochromic reflective element comprises an electrochromic medium disposed between said second surface of said front substrate and said third surface of said rear substrate;

wherein said interior rearview mirror assembly comprises an ambient light sensor operable to sense ambient light and wherein said ambient light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit;

wherein said interior rearview mirror assembly comprises a glare light sensor operable to sense glare light and wherein said glare light sensor comprises a silicon photo-sensor and associated circuitry commonly formed as a monolithic CMOS integrated circuit;

wherein said interior rearview mirror assembly comprises a control operable to establish a reflectance level of said transflective electrochromic reflective element, wherein said control is responsive to light detection by at least one of said ambient light sensor and said glare light sensor;

a backlit video screen 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 backlit video screen is displaying information, and substantially non-viewable by the driver of the vehicle when said backlit video screen is not displaying information;

a display intensity control for adjusting display intensity of said backlit video screen, 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 of said backlit video screen is adjusted as a function of a ratio of a glare light value sensed by said glare light sensor to an ambient light value sensed by said ambient light sensor, and wherein said function comprises at least one of (a) a step function, (b) a linear function, (c) a logarithmic function and (d) a continuous function.

22. The interior rearview mirror system of claim 21, wherein said function is influenced by a modulating effect of said transflective electrochromic reflective element.

23. The interior rearview mirror system of claim 21, 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 said modulating effect, GV is the glare light value; and

AV is the 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.