Photo-sensor cell suitable for IC chip

  • US 5,055,668 A
  • Filed: 03/22/1990
  • Issued: 10/08/1991
  • Est. Priority Date: 05/24/1989
  • Status: Expired due to Fees
  • ×
    • Pin Icon | RPX Insight
    • Pin
First Claim
Patent Images

1. A photo-sensor cell, comprising:

  • (a) first light sensing means for generating two different switched digital level signals when incident light rises beyond or drops below a first threshold;

    (b) second light sensing means for generating two different switched digital level signals when said incident light rises beyond or drops below a second threshold higher than said first threshold;

    (c) first latching means responsive to said first light sensing means, for latching only two different switched digital level signals without latching two of the same digital level signals;

    (d) second latching means responsive to said second light sensing means, for latching only two different switched digital level signals without latching two of the same digital level signals; and

    (e) output logic means responsive to said first and second latching means, for generating a digital output signal from a time when said incident light rises beyond said second threshold to a time when said incident light drops below said first threshold, and having a hysteresis loop for said digital output signal with respect to said incident light.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×