US 4,785,171 AGranted

Fingerprint acquisition system with a fiber optic block

AssigneeFingerprint Technology, Inc.

InventorsRobert F. Dowling, Jr., Keith L. Knowlton

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Abstract

A characteristic pattern acquisition system provides a block comprised of a bundle of optical fibers longitudinally aligned in parallel relation each having an imaging end perpendicular to a major longitudinal axis of the block and a detecting end which is angled, and a source of light directed toward through the imaging end to illuminate the detecting end, the detecting end serving to reflect internal light rays only when the medium outside the detecting end of each fiber has a refractive index less than the optical medium of the fibers. The composite reflection of light from the angled surfaces of the fibers create at the imaging end a reproduction of a characteristic pattern such as the relief features of a fingertip applied to the detecting end of the fiberoptic block. Means are directed toward the imaging end of the fiberoptic block for electronically transmitting an image thereon of the characteristic pattern which is placed on the fiberoptic block detecting end.

Claims26

Dependent claims

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, and
means 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.

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, opposite the first detecting end face, for projecting an image of a characteristic pattern placed upon said detecting end face, said fiberoptic block comprising a bundle of adjacent essentially parallel optical fibers 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 said imaging end face of said fiberoptic block to illuminate a characteristic pattern placed upon said detecting end face;
and
a video camera 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.

1 more element

Dependencies are inferred from the claim text.