IMPULSE OPERATED, DAY-NIGHT, REAR VIEW MIRROR

• US 3,839,663 A
• Filed: 04/16/1973
• Issued: 10/01/1974
• Est. Priority Date: 09/15/1971
• Status: Expired due to Term

• Current Assignee: John W. Brean, Yervand Mathevosian
• Original Assignee: John W. Brean, Yervand Mathevosian
• Inventors: Brean, John W., Mathevosian, Yervand
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US05/351,559
• Time in Patent Office: 533 Days
• Field of Search: 318/480
• US Class Current: 318/480
• CPC Class Codes: B60R 1/087 with remote or automatic control means

Abstract

A day-night mirror for a vehicle, photo-electrically controlled in response to light directed from rearwardly of the vehicle and to ambient light, impinging respectively on photocells which via capacitive coupling control the motion of a reversible motor, in the form of a bifilar solenoid, so that only a change in status of the photocells is communicated to the motor in the form of a pulse leaving the motor to be freely actuated manually absent such a pulse, and also reducing the current drain in the system.

Claims

1. A photo-resistor controlled motor circuit, comprising a backward looking photo-resistor, a side looking photo-resistor, means connecting said photo-resistors in series across a voltage supply, thereby establishing a junction between said photoresistors, a bistable solid state flip-flop circuit having one or another state according as said junction is sustained at a reference value in response to intensity of illumination of said photo-resistors or departs substantially from said reference value in response to differential illumination of said photoresistors, separate normally non-conductive solid state switches connected respectively to supply current to said motor in opposite senses from said voltage supply and capacitive means coupling said switches to said motor in response only to transfer of said bistable circuit in its alternative states and only during such transfers.

2. The combination according to claim 1, wherein said motor is a solenoid including armature means and coil means for actuating said armature means, said solid state switches comprising a first normally non-conductive solid state switch connected in series with said coil means, a second normally non-conductive solid state switch connected in series with said coil means, and said coupling means including ac coupling circuits for transferring only transient control pulses of opposite polarities to said solid state switches, respectively, only during changes of state of said bistable solid state circuit.