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Semiconductor integrated circuit for measuring distance for automatic focusing

  • US 5,185,517 A
  • Filed: 02/05/1992
  • Issued: 02/09/1993
  • Est. Priority Date: 02/07/1991
  • Status: Expired due to Term
First Claim
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1. An automatic focusing device including a semiconductor integrated circuit for measuring distance having a light-detecting element for receiving light from an object, the distance to the object is to be measured, and outputting a light-detecting signal according to the distance to the object, the semiconductor integrated circuit mounted in one chip and comprising:

  • distance measurement arithmetic means for forming digital distance measurement data inversely proportional to the distance to the object from the light-detecting signal from the light-detecting element;

    memory means for writing therein two items of distance measurement data output from said distance measurement arithmetic means with regard to two known distances in a calibration mode; and

    data arithmetic means for computing in a distance measuring mode a control signal of the automatic focusing device from said two items of distance measurement data stored in said memory means and digital distance measurement data output from said distance measurement arithmetic means.

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