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Fingerprint acquisition system with a fiber optic block

  • US 4,785,171 A
  • Filed: 01/15/1987
  • Issued: 11/15/1988
  • Est. Priority Date: 01/15/1987
  • Status: Expired due to Fees
First Claim
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1. A characteristic pattern acquisition system comprising:

  • a fiberoptic block having a first end face for detecting a characteristic pattern placed thereon and a second imaging end face, the imaging end face being opposite the detecting end face for projecting an image of a characteristic pattern placed upon said detecting end face and for receiving light rays from a light source, said fiberoptic block comprising a bundle of optical fibers in adjacent parallel relationship having light ray-guiding cores, the optical fibers having opposite free end faces terminating in and forming said detecting and imaging end faces, respectively, the individual optical fiber detecting end faces each being angled such that when there is present outside the fiber detecting end face a medium, having an index of refraction less than that of the fiber core, parallel light rays in said fiber core are prevented from exiting through the fiber detecting end face while at least a portion of non-parallel light rays in said fiber core are permitted to internally reflect at the fiber detecting end face and reverse direction in said fiber;

    a light source directed through the imaging end face of the fiberoptic block to illuminate a characteristic pattern placed upon the detecting end face of the fiberoptic block, andmeans directed toward the imaging end face of the fiberoptic block for electronically transmitting said image of a characteristic pattern placed upon said fiberoptic block detecting end face.

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