Liquid Crystal Mirror Adapted to Filter Light In the Mesopic Wavelength Region

• US 20090109393A1
• Filed: 06/20/2006
• Published: 04/30/2009
• Est. Priority Date: 09/21/2005
• Status: Active Grant

• Current Assignee: Alphamicron Incorporated
• Original Assignee: Alphamirror, Inc.
• Inventors: Taheri, Bahman, Borenstein, Yehuda
• Granted Patent: US 8,736,805 B2
• Time in Patent Office: Days
• 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
• CPC Class Codes: G02F 1/13 based on liquid crystals, e.g. single liquid crystal display cells
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector

Abstract

A mirror system, comprising a spectrally selective liquid crystal reflective assembly, designed and constructed to substantially absorb or transmit light at wavelengths corresponding to mesopic conditions, while reflecting light at other wavelengths. In one embodiment, the reflectance level of the mirror system is altered in response to a voltage applied across the selective liquid crystal reflective assembly.

Claims

1. A mirror system, comprising a spectrally selective liquid crystal reflective assembly designed and constructed to substantially absorb or transmit light at wavelengths corresponding to mesopic conditions, while reflecting light at other wavelengths.

2. The system of claim 1, wherein said liquid crystal reflective assembly comprises a liquid crystal medium being characterized by an absorption curve having a peak at a wavelength of about 520 nanometers and a width of about 50 nanometers.

3. The system of claim 1, wherein said liquid crystal reflective assembly comprises a liquid crystal medium capable of at least partially absorbing light at wavelengths of from about 490 nanometers to about 550 nanometers, while substantially absorbing light at other wavelengths.

4. The system of claim 1, wherein said liquid crystal reflective assembly is responsive to voltage in a manner such that when a said voltage is applied across said liquid crystal reflective assembly, a reflectance level of said liquid crystal reflective assembly is altered.

5. The system of claim 4, further comprising an electronic circuitry for varying a level of said voltage at a predetermined rate thereby to alter a reflectance level of said liquid crystal reflective assembly at said predetermined rate.

6. The system of claim 5, wherein said electronic circuitry is designed and configured to receive ambient light information and rear light information, and to select said level of said voltage and said predetermined rate based on said ambient light information, said rear light information or a combination of said ambient light information and said rear light information.

7. The system of claim 6, further comprising an ambient light sensor for collecting and transmitting said ambient light information to said electronic circuitry, and a rear light sensor for collecting and transmitting said rear light information to said electronic circuitry.

8. The system of claim 6, wherein said ambient light information and said rear light information each independently comprises light illuminance information.

9. The system of claim 6, wherein said ambient light information and said rear light information each independently comprises light brightness information.

10. The system of claim 6, wherein said ambient light information and said rear light information each independently comprises light spectral information.

11. The system of claim 6, further comprising a user interface communicating with said electronic circuitry.

12. The system of claim 11, wherein said electronic circuitry is designed and configured to receive from said user interface a characteristic response information of a user to light and to weight said predetermined rate based on said characteristic response information.

13. The system of claim 6, wherein said predetermined rate is selected from a set of discrete rates, each rate of said set of discrete rates corresponding to a different ambient light condition.

14. The system of claim 13, wherein each rate of said set of discrete rates corresponds to a different illuminance range of said ambient light and/or said rear light.

15. The system of claim 13, wherein each rate of said set of discrete rates corresponds to a different brightness range of said ambient light and/or said rear light.

16. The system of claim 13, wherein each rate of said set of discrete rates corresponds to a different predominant wavelength range of said ambient light and/or said rear light.

17. The system of claim 6, wherein said predetermined rate is a monotonic decreasing function of an illuminance of said ambient light and/or said rear light.

18. The system of claim 6, wherein said predetermined rate is a monotonic decreasing function of a brightness of said ambient light and/or said rear light.

19. The system of claim 6, wherein said predetermined rate is a non-monotonic function of a predominant wavelength of said ambient light and/or said rear light.

20. The system of claim 6, wherein said electronic circuitry is designed and configured to vary said level of said voltage at a continuous or step-wise varying rate.

21. The system of claim 5, serving as a rearview mirror of a vehicle.

22. The system of claim 5, serving as an interior rearview mirror of a vehicle.

23. The system of claim 5, serving as an exterior rearview mirror of a vehicle.