An advanced fingerprint sensor LSI and its application to a fingerprint identification system

We developed an advanced fingerprint sensor LSI that features a novel sensor structure, sensing circuit, and calibration circuit, using the 0.5-/spl mu/m CMOS process/sensor process. The LSI is reliable, sensitive, and tolerant to changes in the sensor surface conditions for capturing clear fingerprint image over long-term use. We also introduce a fingerprint-image adjustment scheme with an adjustable A/D converter to obtain image quality suitable for identification. The fingerprint sensor LSI was applied to a fingerprint identification system with the fingerprint-image adjustment scheme and achieved sufficient performance for a practical fingerprint identification system.