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Optical coordinate input device having light adjusting means located in front of each light receiving means

  • US 4,771,170 A
  • Filed: 08/19/1987
  • Issued: 09/13/1988
  • Est. Priority Date: 10/31/1986
  • Status: Expired due to Fees
First Claim
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1. In a coordinate input device of the light detection type which includes an optical element train in the form of a framework which is constituted from a large number of light emitting elements and a large number of corresponding light receiving elements both arranged in rows and wherein a position at which light paths defined in front of a display surface of a display device between said light emitting elements and said light receiving elements are interrupted is detected to input coordinates of the position on the display surface of the display device, the improvement which comprises light amount adjusting means of the transmissive type located in front of light receiving portions of said light receiving elements, and controlling means for controlling the amount of light to be passed through said light amount adjusting means in response to an amount of light incident to said light receiving elements.

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