AUTOMATIC REAR VIEW MIRROR ADJUSTER

• US 3,862,798 A
• Filed: 11/19/1973
• Issued: 01/28/1975
• Est. Priority Date: 11/19/1973
• Status: Expired due to Term

• Current Assignee: Charles L. Hopkins
• Original Assignee: Charles L. Hopkins
• Inventors: Hopkins, Charles L.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Chatmon, Jr., Saxfield
• Application Number:
  US05/417,276
• Time in Patent Office: 435 Days
• Field of Search: 250/230,267 74/51M 350/268,278,279,283,16LC,307
• 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: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• CPC Class Codes: Y10T 74/20432 for moving a mirror

Abstract

A rear view mirror assembly comprising a reflective surface, and a liquid crystal assembly covering the reflective surface. The liquid crystal assembly comprises a thin layer of liquid nematic material sandwiched between rigid panes of transparent material, the rigid panes having a thin, transparent coating of conductive material thereon in uniform contact with the nematic material. The nematic material has a quiescent transparent state with no voltage applied and a turbulent opaque state when voltage is applied with the opaqueness being directly related to the applied voltage. A voltage source is supplied and a photocell or a similar light-responsive device is used for controlling the voltage output of the voltage source. The controlled output of the voltage source is applied to the coatings of conductive material. The photocell is effective, when light impinges thereon, to apply a voltage level to the nematic material.

Claims

1. A rear view mirror assembly comprising a plate providing a reflective surface, a layer of liquid crystal compound in front of said reflective surface, said compound being essentially transparent in its quiescent state and opaque when voltage is applied thereto, a voltage source, light-responsive means controlling said voltage source, and electrical means for connecting said voltage source to said compound, said lightresponsive means being effective, when a predetermined light level impinges thereon, to apply a corresponding voltage level to said compound, said light-responsive means including a photocell having a resistance which decreases when light impinges thereon, said electrical means including resistive means connected in series with said photocell to provide a voltage divider network across said voltage source, said network having an output voltage terminal connected to one side of said compound and a ground terminal connected to the other side of said compound.

2. The invention of claim 1 in which said resistive means includes an adjustable resistor such that the sensitivity of the assembly can be adjusted to establish said predetermined level of light.

3. A rear view mirror assembly comprising a plate providing a reflective surface, a layer of liquid crystal compound in front of said reflective surface, said compound being essentially transparent in its quiescent state and opaque when voltage is applied thereto, a voltage source, light-responsive means controlling said voltage source, and electrical means for connecting said voltage source to said compound, said light-responsive means being effective, when a predetermined light level impinges thereon, to apply a corresponding voltage level to said compound, and a manually-operable switch connected in parallel with said light-responsive means such that a voltage can be manually applied to said compound, by-passing said light-responsive means.

4. A rear view mirror assembly comprising means providing a reflective surface, and a liquid crystal assembly covering said reflective surface, said liquid crystal assembly comprising a thin layer of liquid nematic material sandwiched between rigid panes of transparent material, said rigid panes having a thin transparent coating of conductive material thereon in uniform contact with said nematic material, said nematic material having a quiescent transparent state with no voltage applied and a turbulent opaque state when voltage is applied with the opaqueness being directly related to the applied voltage, a voltage source, light-responsive means for controlling the voltage output of said voltage source, and electrical means for connecting said voltage source to said coatings of conductive material, said light-responsive means being effective, when light impinges thereon, to apply a corresponding voltage level to said nematic material, said light-responsive means including a photocell having a resistance which decreases when light impinges thereon, said electrical means including resistive means connected in series with said photocell to provide a voltage divider network across said voltage source, said network having an output voltage terminal connected to one of said conductive coatings and a ground terminal connected to the other of said conductive coatings.

5. The invention of claim 4 in which said resistive means includes an adjustable resistor such that the sensitivity of the assembly can be adjusted selectively to establish the amount of light required to develop said corresponding voltage.

6. A rear view mirror assembly comprising means providing a reflective surface, and a liquid crystal assembly covering said reflective surface, said liquid crystal assembly comprising a thin layer of liquid nematic material sandwiched between rigid panes of transparent material, said rigid panes having a thin transparent coating of conductive material theReon in uniform contact with said nematic material, said nematic material having a quiescent transparent state with no voltage applied and a turbulent opaque state when voltage is applied with the opaqueness being directly related to the applied voltage, a voltage source, light-responsive means for controlling the voltage output of said voltage source, and electrical means for connecting said voltage source to said coatings of conductive material, said light-responsive means being effective, when light impinges thereon, to apply a corresponding voltage level to said nematic material, said light-responsive means including a light-actuated transistor having an emitter-collector path connected between said voltage source and one of said conductive coatings, said other conductive coating being connected to ground, said electrical means including resistive means connected between the emitter of said transistor and ground.