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Optical proximity sensor with ambient light and temperature compensation

  • US 9,146,304 B2
  • Filed: 09/10/2012
  • Issued: 09/29/2015
  • Est. Priority Date: 09/10/2012
  • Status: Active Grant
First Claim
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1. A light-based proximity sensor, comprising:

  • a light source that emits light towards an external object;

    a photodetector that is configured to measure light from the light source that has reflected off of the external object;

    an ambient light correction circuit that corrects signals from the photodetector for photodetector efficiency changes due to changes in how much ambient light is received by the photodetector; and

    an efficiency correction factor generator interposed between the photodetector and the ambient light correction circuit, wherein the ambient light correction circuit comprises a first input that receives an efficiency correction factor signal from the efficiency correction factor generator and a second input that receives an uncorrected photodetector signal from the photodetector.

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