A 500 dpi capacitive-type CMOS fingerprint sensor with pixel-level adaptive image enhancement scheme

A 500 dpi capacitive CMOS fingerprint sensor with pixel-level adaptation image enhancement uses virtually-grounded metal shields to suppress parasitic capacitances and capacitive switching networks to generate local threshold level. A 210×100 sensor in 0.6 μm CMOS consumes 40 mW at 5 V supply.