A 600-dpi capacitive fingerprint sensor chip and image-synthesis technique

This paper examines the possibility of a low-cost, high-resolution fingerprint sensor chip. The test chip is composed of 64/spl times/256 sensing cells (chip size: 2.7/spl times/10.8 mm/sup 2/). A new detection circuit of charge sharing is proposed, which eliminates the influences of internal parasitic capacitances. Thus, the reduced sensing-capacitor size enables a high resolution of 600 dpi, even using a conventional 0.6 /spl mu/m CMOS process. The partial fingerprint images captured are synthesized into a full fingerprint image with an image-synthesis algorithm. The problems and possibilities of this image-synthesis technique are also analyzed and discussed.