Importance

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Abstract

An electrical method and apparatus for sensing the pattern of ridges and valleys on an individual's finger to provide binary electrical signals representative of the sensed pattern. The fingerprint sensor is constructed and defined with an integrated circuit chip having an array of sensing circuits arranged thereon in rows and columns for defining X, Y coordinates. One of the electrodes for each sensing circuit is connected to a contact pad that is electrically exposed on the surface of the integrated circuit chip at a location corresponding to the X, Y coordinate for the individual sensing circuit. A pressure sensitive membrane having a conductive surface facing the array of contact pads is utilized for translating the fingerprint pattern into a conductive pattern of ridges and valleys. The conductive pattern is pressed into electrical engagement with each contact pad opposite a fingerprint ridge. While the conductive pads are in electrical engagement with the membrane, the sensing circuits are sequentially scanned in a preselected timed relationship to produce a binary electrical signal from each sensing circuit having its individual contact pad in circuit relationship with the membrane. The output signals from the rows and columns of sensing signals represent the portion of the fingerprint pattern representative of a ridge. The binary output signals can be processed by known techniques for comparing the sensed fingerprint with known fingerprint patterns.

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First Claim