Patent ID: 7683639
Filing Date: 2010-03-23
Classification: G06K

Abstract:
1. A capacitive fingerprint sensor, comprising: a first transistor having a gate terminal, an input terminal and an output terminal, wherein the gate terminal is controlled by a first readout select line, and the input terminal is connected to a bias voltage VA; a fingerprint capacitor connected to the output terminal of the first transistor, wherein the fingerprint capacitor has a capacitance that is either a valley capacitance C a reference capacitor, wherein one end of the reference capacitor is connected to the output terminal of the first transistor, and the other end of the reference capacitor is connected to a second readout select line, wherein the second readout select line is immediately next to the first readout select line, and the reference capacitor has a capacitance C a second transistor having a gate terminal, an input terminal and an output terminal, wherein the gate terminal is controlled by a scan line, the input terminal is connected to the reference capacitor, and the output terminal is connected to a readout line.