Light-responsive control device of electrochromic rearview mirror system

• US 20030122059A1
• Filed: 02/13/2003
• Published: 07/03/2003
• Est. Priority Date: 09/04/2001
• Status: Active Grant

• Current Assignee: Exon Science, Inc.
• Original Assignee: Exon Science, Inc.
• Inventors: Hsiao, Shun-Hsiang, Chen, Kuei-Hung, Su, Wen-Wei
• Granted Patent: US 6,967,318 B2
• Time in Patent Office: Days
• US Class Current: 250/214B
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors

Abstract

A light-responsive control device of an electrochromic rearview mirror system is disclosed. The light-responsive control device includes a downward ambient light sensor and a, discriminating circuit for generating a first and a second reference levels provided for daytime and nighttime glaring determination, respectively. By providing a photo-sensor for each rearview mirror, and individually comparing the outputs of the photo-sensors with the first or the second reference level, the color-change degrees of different rearview mirrors can be individually controlled. By providing a variable resistor for the drive circuit, the initial reflection rate of the rearview mirror can be adjusted optionally.

Claims

1. A light-responsive control device of an electrochromic rearview mirror system of a vehicle, said electrochromic rearview mirror system including a first rearview mirror and a first electrochromic unit for changing a reflection rate of said first rearview mirror in response to a voltage applied thereto, and said light-responsive control device comprising:

a first photo-sensor disposed on said vehicle and oriented downwards for generating a first signal in response to an intensity of ambient light;

a second photo-sensor disposed at a back side of said first rearview mirror for generating a second signal in response to an intensity of a rear light reaching said first rearview mirror;

a discriminating circuit electrically connected to said first and second photo-sensors, determining which of a first and a second predetermined signals to serve as a reference signal in response to said first signal, and generating a first adjusting signal in response to a comparing result of said second signal and said reference signal; and

a drive circuit electrically connected to said discriminating circuit and said first electrochromic unit for providing a first variable drive voltage for said first electrochromic unit in response to said first adjusting signal.

2. The light-responsive control device according to claim 1 wherein said discriminating circuit includes:

a first comparing unit electrically connected to said first photo-sensor for comparing said first signal with a third predetermined signal to determine which of said first and second predetermined signals to serve as said reference signal; and

a second comparing unit electrically connected to said second photo-sensor and said first comparing unit for comparing said second signal with said reference signal to generate said first adjusting signal.

3. The light-responsive control device according to claim 1 wherein said first photo-sensor is disposed at a lower surface of said first rearview mirror.

4. The light-responsive control device according to claim 1 further comprising:

a third photo-sensor disposed at a driver'"'"'s side outside said vehicle for generating a third signal in response to an intensity of a rear light reaching a second rearview mirror of said electrochromic rearview mirror system; and

a fourth photo-sensor disposed at a passenger'"'"'s side outside said vehicle for generating a fourth signal in response to an intensity of a rear light reaching a third rearview mirror of said electrochromic rearview mirror system.

5. The light-responsive control device according to claim 4 wherein said discriminating circuit is further electrically connected to said third and fourth photo-sensors, and generates a second adjusting signal in response to a comparing result of said third signal and said reference signal, and a third adjusting signal in response to a comparing result of said fourth signal and said reference signal, and said drive circuit provides a second and a third variable drive voltages for said second and third electrochromic units in response to said second and third adjusting signals, respectively.

6. The light-responsive control device according to claim 4 wherein said discriminating circuit includes:

a first comparing unit electrically connected to said first photo-sensor for comparing said first signal with a third predetermined signal to determine which of said first and second predetermined signals to serve as said reference signal;

a second comparing unit electrically connected to said second photo-sensor and said first comparing unit for comparing said second signal with said reference signal to generate said first adjusting signal;

a third comparing unit electrically connected to said third photo-sensor and said first comparing unit for comparing said third signal with said reference signal to generate said second adjusting signal; and

a fourth comparing unit electrically connected to said fourth photo-sensor and said first comparing unit for comparing said fourth signal with said reference signal to generate said third adjusting signal.

7. The light-responsive control device according to claim 1 further comprising a reflectance-adjusting unit between said drive circuit and said first electrochromic unit for determining a maximum reflection rate of said first electrochromic unit.

8. The light-responsive control device according to claim 7 wherein said reflectance-adjusting unit includes a variable resistor.

9. A light-responsive control device of an electrochromic rearview mirror system of a vehicle, said electrochromic rearview mirror system including a first and a second rearview mirror assemblies, said first rearview mirror assembly including a first rearview mirror and a first electrochromic unit for changing a reflection rate of said first rearview mirror in response to a first voltage applied thereto, said second rearview mirror assembly including a second rearview mirror and a second electrochromic unit for changing a reflection rate of said second rearview mirror in response to a second voltage applied thereto, and said light-responsive control device comprising:

a first photo-sensor disposed on said vehicle and oriented downwards for generating a first signal in response to an intensity of the ambient light;

a second photo-sensor disposed at a back side of said first rearview mirror for generating a second signal in response to an intensity of a rear light reaching said first rearview mirror;

a third photo-sensor disposed at a back side of said second rearview mirror for generating a third signal in response to an intensity of a rear light reaching said second rearview mirror;

a discriminating circuit electrically connected to said first, second and third photo-sensors, generating a reference signal in response to said first signal, generating a first adjusting signal in response to a comparing result of said second signal and said reference signal, and generating a second adjusting signal in response to a comparing result of said third signal and said reference signal;

a first charge/discharge unit electrically connected to said discriminating circuit and said first electrochromic unit for providing a first variable drive voltage for said first electrochromic unit in response to said first adjusting signal; and

a second charge/discharge unit electrically connected to said discriminating circuit and said second electrochromic unit for providing a second variable drive voltage for said second electrochromic unit in response to said second adjusting signal.

10. The light-responsive control device according to claim 9 wherein said first photo-sensor is disposed at a lower surface of said first rearview mirror.

11. The light-responsive control device according to claim 9 further comprising:

a voltage source for providing an initial voltage signal; and

a voltage-reducing unit electrically connected between said voltage source, and said first and second charge/discharge units for reducing said initial voltage signal to a range suitable for driving said first and second electrochromic units.

12. The light-responsive control device according to claim 9 further comprising:

a fourth photo-sensor disposed at a back side of a third rearview mirror of a third rearview mirror assembly for generating a fourth signal in response to an intensity of a rear light reaching said third rearview mirror, wherein said discriminating circuit is further electrically connected to said fourth photo-sensor, and generates a third adjusting signal in response to a comparing result of said fourth signal and said reference signal; and

a third charge/discharge unit electrically connected to said discriminating circuit and a third electrochromic unit of said third rearview mirror assembly for providing a third variable drive voltage for said third electrochromic unit in response to said third adjusting signal.

13. The light-responsive control device according to claim 12 wherein said discriminating circuit includes:

a first comparing unit electrically connected to said first photo-sensor for comparing said first signal with a third predetermined signal to determine which of a first and a second predetermined signals to serve as said reference signal;

a second comparing unit electrically connected to said second photo-sensor and said first comparing unit for comparing said second signal with said reference signal to generate said first adjusting signal;

a third comparing unit electrically connected to said third photo-sensor and said first comparing unit for comparing said third signal with said reference signal to generate said second adjusting signal; and

a fourth comparing unit electrically connected to said fourth photo-sensor and said first comparing unit for comparing said fourth signal with said reference signal to generate said third adjusting signal.

14. A light-responsive control device of an electrochromic rearview mirror system of a vehicle, said electrochromic rearview mirror system including a first rearview mirror and a first electrochromic unit for changing a reflection rate of said first rearview mirror in response to a voltage applied thereto, and said light-responsive control device comprising:

a first photo-sensor disposed on said vehicle and oriented downwards for generating a first signal in response to an intensity of the ambient light;

a second photo-sensor disposed at a back side of said first rearview mirror for generating a second signal in response to an intensity of a rear light reaching said first rearview mirror;

a discriminating circuit electrically connected to said first and second photo-sensors, generating a reference signal in response to said first signal, and generating a first adjusting signal in response to a comparing result of said second signal and said reference signal;

a reflectance-adjusting unit for selecting a reflection-rate range of said first electrochromic unit according to a user'"'"'s option;

a drive circuit electrically connected to said discriminating circuit, said reflectance-adjusting unit and said first electrochromic unit for providing a first variable drive voltage for said first electrochromic unit in response to said first adjusting signal to result in a reflection rate within said reflection-rate range.

15. The light-responsive control device according to claim 14 wherein said first photo-sensor is disposed at a lower surface of said first rearview mirror.

16. The light-responsive control device according to claim 15 wherein said reflectance-adjusting unit includes a variable resistor electrically connected to said drive circuit and said first electrochromic unit.

17. The light-responsive control device according to claim 15 wherein said reflection-rate range is about 55%˜

8% for a first option, and about 85%˜

8% for a second option.

18. The light-responsive control device according to claim 15 further comprising:

a third photo-sensor disposed at a driver'"'"'s side outside said vehicle for generating a third signal in response to an intensity of a rear light reaching a second rearview mirror of said electrochromic rearview mirror system; and

a fourth photo-sensor disposed at a passenger'"'"'s side outside said vehicle for generating a fourth signal in response to an intensity of a rear light reaching a third rearview mirror of said electrochromic rearview mirror system;

wherein said discriminating circuit is further electrically connected to said third and fourth photo-sensors, and generates a second adjusting signal in response to a comparing result of said third signal and said reference signal, and a third adjusting signal in response to a comparing result of said fourth signal and said reference signal, and said drive circuit provides a second and a third variable drive voltages for said second and third electrochromic units in response to said second and third adjusting signals, respectively.

19. The light-responsive control device according to claim 18 wherein said discriminating circuit includes:

a first comparing unit electrically connected to said first photo-sensor for comparing said first signal with a third predetermined signal to determine which of said first and second predetermined signals to serve as said reference signal;

a second comparing unit electrically connected to said second photo-sensor and said first comparing unit for comparing said second signal with said reference signal to generate said first adjusting signal;

a third comparing unit electrically connected to said third photo-sensor and said first comparing unit for comparing said third signal with said reference signal to generate said second adjusting signal; and

a fourth comparing unit electrically connected to said fourth photo-sensor and said first comparing unit for comparing said fourth signal with said reference signal to generate said third adjusting signal.

20. The light-responsive control device according to claim 19 wherein said drive circuit includes three charge/discharge units electrically connected between said second, third and fourth comparing units and said first, second and third electrochromic units for charging/discharging said first, second and third electrochromic units in response to said first, second and third adjusting signals, respectively, and said reflectance-adjusting unit includes three variable resistors electrically connected to said three charge/discharge units, respectively, for separately determining said reflection-rate ranges of said first, second and third electrochromic units.