UNIT PIXEL OF CAPACITIVE TYPED FINGERPRINT SENSOR USING LOCATION ADAPTATION IMAGE ENHANCEMENT SCHEME BY ANALYZING DIVERSE BRIGHTNESS, AND FINGERPRINT DETECTOR USING THE SAME

摘要

PURPOSE: A unit pixel of a capacitive typed fingerprint sensor using a location adaptation image enhancement scheme and a fingerprint detector using the same are provided to obtain a fingerprint image more correctly by analyzing diverse brightness on a surface of a finger. CONSTITUTION: A detector(20) senses the fingerprint image. A switched-capacitor amplifier(21) uses output of the detector and a reference value as different inputs, amplifies a variance of a voltage level corresponding to the stored charges detected by the detector through the variance of the reference voltage, and outputs the amplified variance through an output terminal. A row/column direction connector(22) obtains the fingerprint image through the location adaptation image enhancement scheme making the output terminals of the unit pixels neighboring in the row/column direction commonly connected to the output terminal, obtaining a local reference value through the average including the output and the output of the connected neighboring unit pixels, and comparing the values of the output terminal by using the local reference value.