Method and apparatus for illuminating a fingerprint through side illumination of a platen
AssigneeDigital Persona, Inc.
InventorKenneth Brownlee
Life of this patent
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Abstract
The present invention provides a method and apparatus for illuminating a fingerprint. A finger is placed on a transparent platen which has a microprism array on one surface. A light source directs light through a horizontal plane of the platen to illuminate the finger. Light directed through the platen is substantially parallel to an axis of the microprism array and is largely contained within the body of the platen. The skin in contact with the platen is illuminated by the light, and the light is imaged by an imaging device.
Claims21
An apparatus for illuminating a fingerprint comprising:
- a transparent platen having sensing surface, a bottom surface, and sides, one of the surfaces including a microprism array;
- and
- a light source positioned to direct light through a horizontal plane of the platen substantially parallel to an axis of the microprism array, the fingerprint illuminated using multiple total-internal-reflection (TIR) bounces of light rays down the plane of the platen, between the microprism array and the other surface to reach points of skin contact.
A method for illuminating a fingerprint comprising:
- receiving a finger on a transparent platen having sensing surface, a bottom surface, and sides, one of the sensing surfaces including a microprism array;
- and
- illuminating the fingerprint with a light source positioned to direct light through a horizontal plane of the platen substantially parallel to an axis of the microprism, the fingerprint illuminated using multiple total-internal-reflection (TIR) bounces of light rays down the plane of the platen, between a first surface and the microprism array to reach points of skin contact.
Dependencies are inferred from the claim text.