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A thin, inexpensive, removable platen for a direct fingerprint reader without a permanently attached platen. A removable platen is formed as a transparent area on a credit card, passport or identification card or as a separate card. The portable platen on the card is inserted over an imaging area of

A thin, inexpensive, removable platen for a direct fingerprint reader without a permanently attached platen. A removable platen is formed as a transparent area on a credit card, passport or identification card or as a separate card. The portable platen on the card is inserted over an imaging area of the direct fingerprint reader. Light from the direct fingerprint reader passes through an optical surface formed on the underside of the portable platen, is reflected off the fingerprint and passes back through the optical surface to the imaging apparatus where the image is digitized and analyzed. The optical surface is formed such that the incident light is not refracted away from the fingerprint and the reflected light from the fingerprint is not refracted away from the imaging apparatus.

대표청구항 ▼

[ What is claimed is:] [1.] An optical system for acquiring a fingerprint image, comprising:a housing defining an imaging aperture;an incoherent light source directing light toward said imaging aperture at a non-normal angle;an array of light sensors to receive sensed working image signals indicativ

[ What is claimed is:] [1.] An optical system for acquiring a fingerprint image, comprising:a housing defining an imaging aperture;an incoherent light source directing light toward said imaging aperture at a non-normal angle;an array of light sensors to receive sensed working image signals indicative of a fingerprint image; anda platen affixed to said housing over said imaging aperture, said platen including a light receiving side and a fingerprint receiving side, said fingerprint receiving side receiving a fingerprint that produces fingerprint flesh regions and fingerprint valley regions on said fingerprint receiving side, said light receiving side including a plurality of adjacent optical structures that reduce the reflection of non-working image light signals from said light receiving side and pass working image light signals, said working image light signals being reflected at said fingerprint valley regions to produce a light portion of said sensed working image signals and passing through said fingerprint flesh regions to produce a dark portion of said sensed working image signals.