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Battery-operated data collection apparatus having an infrared touch screen data entry device

  • US 4,928,094 A
  • Filed: 01/25/1988
  • Issued: 05/22/1990
  • Est. Priority Date: 01/25/1988
  • Status: Expired due to Fees
First Claim
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1. Photoelectric apparatus comprising:

  • an emitter element for intermittently emitting a beam of electromagnetic radiation,a detector element for receiving radiation emitted by the emitter element, the detector element having a semiconductor junction and having an output terminal at which a voltage representative of intensity of electromagnetic radiation falling on the junction is developed, andswitch means for intermittently grounding the output terminal of the detector element when the emitter element is not emitting the beam of electromagnetic radiation.

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