Rain-controlled windshield wipers

  • US 4,620,141 A
  • Filed: 07/03/1985
  • Issued: 10/28/1986
  • Est. Priority Date: 07/03/1985
  • Status: Expired due to Term
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First Claim
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1. In a motor vehicle of the type incorporating a windshield and a motor-driven windshield wiper, an improved windshield wiper motor controller for automatically activating the motor of said motor-driven windshield wiper upon detection of moisture droplets on the exterior surface of said windshield, comprising:

  • (a) an opaque housing secured to the inside surface of said windshield, said housing having a first and a second plurality of bores whose longitudinal axes intersect at points at the exterior surface of said windshield and at an acute angle to the plane of the windshield, said first plurality of bores including individual radiant energy sources and said second plurality of bores including individual radiant energy sensors, individual ones of said sources being associated with individual ones of said sensors;

    (b) driver means for periodically energizing said radiant energy sources with pulses of a predetermined duty cycle;

    (c) balanced detector means coupled to said plurality of radiant energy sensors for detecting changes in the amount of light energy from said individual radiant energy sources impinging on its associated radiant energy sensor, and producing an error signal proportional to the degree of unbalance of said detector means;

    (d) synchronous switching means coupled to said driver means for switching said error signal on and off in synchronism with said pulses from said driver means;

    (e) comparator means coupled to said synchronous switching means for producing a voltage output when the amplitude of said error signal falls outside of a predetermined range of amplitudes; and

    (f) a voltage-controlled oscillator having an input and an output, said input being coupled to receive said voltage output of said comparator means and said output being coupled in controlling relation to said motor.

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