IMPULSE-OPERATED, DAY-NIGHT, REAR VIEW MIRROR

• US 3,746,430 A
• Filed: 09/15/1971
• Issued: 07/17/1973
• 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): Corbin, John K.
• Application Number:
  US05/180,547
• Time in Patent Office: 671 Days
• Field of Search: 350/279-283
• US Class Current: 359/604
• 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 current drain in the system.

Claims

1. A mirror having a reflective panel which is movable between two stable positions for providing a relatively bright reflected image at a viewing position when in one of said positions and a relatively weak reflected image at said viewing position when in the other of said positions, electric motor means for moving said panel to said positions, a first photo-resistor means including normally non-conductive solid state bistable switch circuit means responsive only to decreases of light intensity to values below a predetermined level, said bistable switch circuit including solely capacitive coupling circuits connected between said bistable switch circuit means and said motor means, for only impulsively energizing said motor means in response to change of state of said bistable switch circuit to drive said reflective panel to said one position and responsive to increases of light intensity above said predetermined level for only impulsively energizing said motor means for moving said panel to said other position, and a second photo-resistor means responsive to steady state ambient light intensity above a predetermined intensity for inhibiting said first photo-resistor means and thereby maintaining said reflective panel in said one position.

2. The combination according to claim 1, further comprising adjustable means for selectively varying said predetermined intensity.

3. The combination according to claim 1, further comprising means for mounting said mirror on a motor vehicle to provide rear view vision for an operator of said motor vehicle, and wherein said second photo-resistor means comprises a photosensitive element mounted to sense ambient light intensity only generally to the adjacent curb side of the motor vehicle operator.

4. In combination, a mirror, a camming device having a translatable cam and a cam follower, a pivot secured to said mirror about which said mirror oscillates angularly between two limiting positions, means linking said cam follower to said mirror so that said mirror oscillates angularly between said two limiting positions as said cam translates between two limiting positions and said cam follower correspondingly moves between two limiting positions, a reversible motor connected to drive said translatable cam between its two limiting positions, a photoelectric bistable circuit control system, including an ambient light sensing photo-resistor and a directionally sensitive light sensiNg photo-resistor, and means including an only ac coupled circuit responsive to said control system for only impulsively energizing said motor in response only to change of state of said bistable circuit control system to actuate said cam to move between its two limiting positions in response to an increase of intensity of high intensity light impacting on said last mentioned photo-resistor while low intensities of ambient light are sensed by both said photo-resistors.

5. The combination according to claim 4, wherein said camming device includes permanent magnet latching means for magnetically latching said follower in its limiting positions.

6. A photocell motor control circuit for a day-night mirror comprising, motor means, a first circuit including a first photoelectric cell exposed to ambient light but not to light directed in a predetermined direction, a second circuit including a second photoelectric cell exposed to said ambient light and also to said light directed only in said predetermined direction, a source of voltage providing electric current, means connecting said circuits in series across said source of voltage and providing a junction between said circuits, a bistable transistor circuit having a transistor base connected to said junction, means driving said bistable circuit into one or another of its stable states according as said junction rises or falls to a predetermined level with respect to the level of a pole of said source of voltage, transistor switching circuits for conveying current selectively from said source of voltage to said motor means so as to drive said motor means selectively in opposite senses, solely ac responsive circuit means responsive to said bistable circuit only during transfer of its state to only transiently control said transistor switching circuits to convey said current to said motor means in impulses only, and a reflective panel movable in alternate directions in response to driving of said motor in said alternate senses.

7. The combination according to claim 6, wherein is provided a resistive circuit connected only across said first photoelectric circuit and having a resistance greater than the resistance of said photoelectric cell when illuminated by said ambient light and less than the resistance of said photoelectric cell when dark.

8. A rear view mirror system for a vehicle, wherein a panel is selectively movable between two stable positions relative to said vehicle for providing via said mirror system at a viewing location a relatively bright reflected image in a first position of said panel and relatively weak reflected image in a second position of said panel, said mirror system including motor means, said motor means including an armature movable in opposite senses in response to oppositely directed currents applied to said motor means, means responsive to said armature in moving in said first sense for moving said panel to said first position and responsive to said armature in moving in said second sense for moving said reflective panel to said second position;

photo-sensitive means for sensing the intensity of light directed toward said reflective panel in comparison with ambient light intensity;

electrical solely ac coupling circuit means which are non-conductive to steady state voltage for directing only transient currents through said motor means in one direction in response to light intensities below a predetermined intensity sensed by said photo-sensitive means, and for directing only transient currents through said motor means in an opposite sense in response to variations only of intensities sensed by said photo-sensitive means which are above said predetermined intensities.