FINGERPRINT SENSOR, FINGERPRINT IMAGE DETECTION METHOD AND PROGRAM FOR MAKING COMPUTER EXECUTE THE SAME METHOD

摘要

PROBLEM TO BE SOLVED: To promptly and accurately detect a fingerprint image without being effected by changes of environmental temperature when the fingerprint image is detected by using heat transmission characteristics of crests and troughs of fingerprints.

SOLUTION: When a voltage pulse is applied on a resistive element 111, the fingerprint image is detected based on a differential signal between current corresponding to temperature at time ts as a time point of rise of the voltage pulse or immediately after the time and current corresponding to temperature at a time point of the fall of the voltage pulse or prescribed time later from immediately after the time point.

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