Drive apparatus for a liquid crystal dazzle-free mirror arrangement

• US 4,676,601 A
• Filed: 04/02/1986
• Issued: 06/30/1987
• Est. Priority Date: 11/14/1983
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Itoh, Hiroshi, Hara, Kunihiko, Fukada, Tsuyoshi, Suzuki, Yasutoshi, Ohmi, Shinya
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/847,142
• Time in Patent Office: 454 Days
• Field of Search: 350/331 R, 350/338, 350/278-281, 350/283, 250/230
• US Class Current: 349/195
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors

Abstract

A drive apparatus for a liquid crystal dazzlement preventing mirror arrangement for automatically setting a liquid crystal panel of the mirror arrangment to a dazzlement preventing state by detecting illuminance on the mirror surface and brightness in region near the mirror. An incident light detecting unit detects incident light onto the mirror. An ambient light detecting unit detects brightness in a region around mirror. A control unit receives both the incident light and the ambient light signals and produces a control signal for driving the liquid crystal panel through a drive unit. The apparatus includes an illuminance descrimination function, which is performed in such a manner that in the event of the illuminance on the mirror surface is higher than first prescribed set value of incident light illuminance and the illuminance in region around the mirror is lower than a prescribed set value of ambient light illuminance, the dazzlement preventing state is provided, and that in the event of the incident light illuminance is higher than a second prescribed set value of incident light illuminance which is higher than that of the first set value, irrespective of the ambient light illuminance, the dazzlement preventing state is also provided.

Claims

1. A dazzlement preventing mirror arrangement for a vehicle comprising:

a rear view mirror assembly mounted on said vehicle and operable in either a dazzlement-preventing state or in a dazzlement non-preventing state;

rear light detecting means for detecting rear light incident to said rear view mirror assembly from the rear of said vehicle and providing a first electrical signal indicative of the detected rear light;

discriminating means for determining an ambient light condition in a region of said rear view mirror assembly and providing a second electrical signal indicative thereof,

dazzle control means, responsive to said first and second electrical signals, for (1) causing said rear view mirror assembly to operate in said dazzlement preventing state when both said detected rear light is higher than a first predetermined level and said ambient light condition meets first predetermined criteria and (2) causing said rear view mirror assembly to operate in said dazzlement preventing state when said detected rear light is higher than a second predetermined level which is higher than said first predetermined level regardless of said ambient light condition.

2. An arrangement according to claim 1 wherein said dazzle control means comprises:

control means, responsive to said first and second electrical signals, for generating a control signal and drive means, responsive to said control signal, for controlling the dazzlement or non-dazzlement state of said mirror assembly.

3. An arrangement according to claim 1 wherein said ambient light condition discriminating means comprises ambient light detecting means for detecting an ambient light level and providing said second electrical signal indicative thereof.

4. An arrangement according to claim 2 wherein said rear view mirror assembly comprises a liquid crystal panel, said dazzle control means driving said liquid crystal panel to reduce the transmittivity thereof in response to said control signal.

5. An arrangement according to claim 3 wherein said ambient light detecting means is mounted on said rear view mirror assembly at a position substantially insensitive to light incident from the rear of said vehicle.

6. A dazzlement preventing mirror arrangement for a vehicle comprising:

a rear view mirror assembly mounted on said vehicle and operable in either a dazzlement-preventing state or in a dazzlement non-preventing state;

rear light detecting means for detecting rear light incident to said rear view mirror assembly from the rear of said vehicle and providing a first electrical signal indicative thereof;

ambient light condition discriminating means for determining an ambient light condition in a region of said rear view mirror and providing a second electrical signal indicative thereof;

first comparing means for comparing said first electrical signal indicative of rear light with a first predetermined level and providing a first output when said detected rear light is higher than said first predetermined level;

second comparing means for comparing said first electrical signal indicative of detected rear light with a second predetermined level higher than said first predetermined level and providing a second output when said detected rear light is higher than said second predetermined level;

logic means, responsive to said first output and said second electrical signal, for providing a third output when said first output is provided and, at the same time, said ambient light condition indicated by said second electrical signal meets predetermined criteria; and

drive means for driving said rear view mirror assembly into said dazzlement-preventing sate in response to said second output or in response to said third output.

7. An arrangement according to claim 6 wherein said rear view mirror assembly comprises a liquid crystal panel, said drive means driving said liquid crystal panel to reduce the transmittivity thereof in response to said control signal.

8. An arrangement according to claim 6 wherein said ambient light condition discriminating means comprises ambient light detecting means for detecting an ambient light level and providing said second electrical signal indicative thereof.

9. An arrangement according to claim 8 wherein said ambient light detecting means is mounted on said rear view mirror assembly at a position insensitive to light incident from the rear of said vehicle.

10. A dazzlement preventing mirror arrangement for a vehicle comprising:

a rear view mirror assembly mounted on said vehicle and operable in either a dazzlement-preventing state or in a dazzlement non-preventing state;

first light detecting means for detecting rear light incident to said rear view mirror assembly from the rear of said vehicle and providing a first output indicating that the detected rear light is higher than a first reference level predetermined to discriminate whether or not said rear light corresponds to intensive headlight from a following vehicle;

second light detecting means for detecting rear light incident to said rear view mirror assembly from the rear of said vehicle and providing a second output indicating that the detected rear light is higher than a second reference level higher than said first reference level predetermined to discriminate whether or not said rear light corresponds to sunlight directly incident to said rear view mirror assembly;

ambient light detecting means for detecting ambient light and providing a third output indicating that ambient light is lower than a third reference level predetermined to discriminate day and night;

control means, responsive to said first, second and third outputs, for (1) providing a control output in response to the simultaneous occurrence of both said first output and said third output and (2) providing a control output in response to said second output regardless of the others; and

drive means for driving said rear view mirror assembly into said dazzlement-prevening state in response to said control signal.

11. An arrangement according to claim 10 wherein said rear view mirror assembly comprises a liquid crystal panel, said drive means driving said liquid crystal panel to reduce the transmittivity thereof in response to said control signal.

12. An arrangement according to claim 10 wherein said ambient light detecting means is mounted on said rear view mirror assembly at a position insensitive to light incident from the rear of said vehicle.