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Device for investigation of a finger relief

  • US 4,385,831 A
  • Filed: 09/22/1980
  • Issued: 05/31/1983
  • Est. Priority Date: 09/22/1980
  • Status: Expired due to Term
First Claim
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1. A device for investigating the pattern of a finger, comprising in combination:

  • (a) a source for emitting a beam of radiation;

    (b) a fingerbed for supporting said finger, said fingerbed defining an opening which leaves free an area of the skin of said finger for investigation, when said finger rests in said fingerbed;

    (c) means for passing said beam of radiation to said area under investigation, said beam thereby forming a spot of impingement on said area which has an extension that is smaller than the distance between two adjacent ridges on said skin under investigation;

    (d) means for raster scanning said impingement spot in two dimensions over said area under investigation, said finger skin area thereby scattering back a beam of radiation which is modulated in accordance with said pattern on said area, said scanning means comprising a reflection hologram which is tiltable about an axis;

    (e) measuring means responsive to said radiation;

    (f) lens means for collecting and transmitting said back-scattered beam of radiation to said measuring means, said measuring means thereby measuring the distribution of the back-scattered radiation in accordance with the ridge-valley pattern of said area under investigation; and

    (g) output means associated with said measuring means for producing an output signal representing the intensity of back-scattered radiation.

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