Dimmable rear view mirror, particularly for automotive vehicles

• US 4,299,444 A
• Filed: 08/07/1980
• Issued: 11/10/1981
• Est. Priority Date: 08/25/1979
• Status: Expired due to Term

• Current Assignee: VDO Adolf Schindling AG (Vodafone Group PLC)
• Original Assignee: VDO Adolf Schindling AG (Vodafone Group PLC)
• Inventors: Romer, Horst
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): de los Reyes, B. W.
• Application Number:
  US06/175,971
• Time in Patent Office: 460 Days
• Field of Search: 350/278, 350/331-335, 350/344, 350/348, 350/202, 350/269, 350/290, 350/312, 350/150-156, 350/337
• 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 1/134309 characterised by their geometrical arrangement

Abstract

A dimmable rearview mirror, particularly for motor vehicles comprising a reflective surface, two polarization filters spaced apart from each other and arranged in front of the reflective surface as seen in the direction of observation. A liquid crystal cell is disposed between the two polarization filters and includes cell glasses enclosing a liquid crystal substance. The cell glasses are provided with electrodes, the electrodes surfacewise covering essentially the entire surface of the reflective surface. A switchable and/or variable source of voltage is connected to the electrodes for adjusting the degree of reflection of the rearview mirror.

Claims

1. A dimmable rearview mirror, particularly for motor vehicles, comprising

a mirror reflective surface constituting a mirror,

a liquid crystal cell covered adjacent a rear side thereof by said reflective surface;

two polarization filters spaced apart from each other,

said liquid-crystal cell being disposed between said two polarization filters,

said liquid-crystal cell includes cell glasses, a liquid-crystal substance enclosed by said cell glasses, and electrodes disposed on said cell glasses,

said electrodes cover substantially the entire surface of said liquid crystal cell next to said liquid-crystal substance,

means including a source of voltage connected to said electrodes for adjusting the degree of reflection of the rearview mirror in the area of the reflective surface,

a display surface at least alongside of said reflective surface formed by one part of the liquid-crystal cell for displaying characters and symbols.

2. The rearview mirror as set forth in claim 1, wherein

said reflective surface is provided on a rear side of a rearmost of said polarization filters and constitutes a mirror surface thereon,

said rearmost polarization filter is disposed behind said liquid-crystal cell as seen in the direction of observation.

3. The dimmable rearview mirror as set forth in claim 1, wherein

a frontmost of said electrodes in said display is structured in electrode elements arranged in accordance with said characters and symbols to be indicated as 7-segment displays, and

control electronics means connected to said electrode elements for operatively displaying the characters and symbols respectively,

4. The rearview mirror as set forth in claim 1, further comprising

means for actuating said voltage source means spaced from the mirror and disposed closely adjacent the driver.

5. The dimmable rearview mirror as set forth in claim 1, further comprising

a frontmost of said electrodes, for simultaneous use of the entire surface of said liquid-crystal cell as an absorption element of the dimmable rearview mirror and as said display, is structured such that electrode surfaces thereof join closely adjacent electrode elements thereof, said display constitutes said electrode elements of said frontmost electrode and said electrode elements and said display extends substantially in front of across the entire visible area of the mirror reflective surface,

said electrode elements are formed in accordance with the characters and symbols to be displayed as 7-segment displays,

control electronics means connected with said electrode elements for operatively displaying the characters and symbols, respectively,

said electrode surfaces are connected with said voltage source means for adjusting the degree of reflection of the rearview mirror.

6. The rearview mirror as set forth in claim 5, further comprising

an adjustable second voltage source means including an oppositely source of voltage compared to said first-mentioned voltage source means is connected with said electrode elements and to a rearmost of said electrodes,

said first-mentioned and said second voltage source means are coupled with each other.

7. The rearview mirror as set forth in claim 1 or 6, wherein

said voltage source means comprise a switchable source of voltage.

8. The rearview mirror as set forth in claim 1 or 6, wherein

said voltage source means comprise a changeable source of voltage.

9. The rearview mirror as set forth in claim 1 or 6, wherein

said voltage source means comprise a switchable and variable source of voltage.

10. The rearview mirror as set forth in claim 6, further comprising

ganged switch means connected to and for the the coupling of said first-mentioned and said second voltage source means for operatively connecting one of said voltage source means, respectively.