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Access control system

  • US 4,222,662 A
  • Filed: 04/04/1979
  • Issued: 09/16/1980
  • Est. Priority Date: 04/04/1979
  • Status: Expired due to Term
First Claim
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1. Apparatus for reading an identification card of the type that includes (1) visible indicia decriptive of an authorized holder;

  • and (2) further visible indicia descriptive of said holder sandwiched between a reflecting medium and a filter which is opaque to visible radiation but substantially transparent to infra-red or ultra violet radiation, said apparatus comprising;

    a source of a beam of infra-red or ultra-violet radiation;

    means for directing said beam of infra-red or ultra-violet radiation onto the surface of said card and substantially normal thereto, thereby to cause said beam to be reflected off said reflecting medium and to be modulated by the information contained by said further visible indicia; and

    means, substantially aligned with the normal to said surface and responsive to said modulated, reflected infra-red or ultra-violet beam, for detecting said further visible indicia.

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