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Transducer for fingerprints and apparatus for analyzing fingerprints

  • US 4,358,677 A
  • Filed: 05/22/1980
  • Issued: 11/09/1982
  • Est. Priority Date: 05/22/1980
  • Status: Expired due to Term
First Claim
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1. In an apparatus for the identification of fingerprints having a fingerprint sensing member with a sensing surface and means for interrogating the sensing surface with a light beam, whereby the light beam is modulated in accordance with the structure of the fingerprint, the improvement comprisingthe sensing surface having a random surface roughness and being made of a material having a softening temperature greater than ambient temperature and close to human body temperature such that when a finger is placed onto the sensing surface, portions of the material will soften to disturb the random surface roughness in accordance with the geometrical structure of the print of the finger, the roughness of disturbed portions of the sensing surface serving to scatter light differently from the roughness of the undisturbed portions.

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