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Increased sensitivity optical keyboard

  • US 4,884,073 A
  • Filed: 12/23/1987
  • Issued: 11/28/1989
  • Est. Priority Date: 04/25/1986
  • Status: Expired due to Fees
First Claim
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1. A matrix-scanning optical keyboard comprising a logical matrix of optical paths between light inlets and light outlets, with keys being disposed on each optical path connecting an inlet to an outlet in such a manner that depressing a key causes a change which is detectable by a scanning driver circuit connected to said light inlets and outlets in order to register such changes affecting each inlet-to-outlet coupling by cyclically injecting an interrogation signal into each inlet in turn and by inspecting each outlet for the presence of possible modifications thereat opto-electronic transducers connected to the scanning driver circuit and photodetectors at the outlets, said keyboard being characterized by the fact that it includes means which are capable for a given emission level of increasing the sensitivity of said scanning driver circuit to light arriving at said outlets.

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