Patent ID: 7187812

Claim:
A fingerprint sensor for sensing a fingerprint, the fingerprint sensor comprising: a detecting and processing circuit; and a plurality of sensing units, each of the sensing units comprising: a switch element comprising a first terminal, a second terminal, and a third terminal, the first terminal is connected to a switch terminal, the third terminal is connected to the detecting and processing circuit, and the switch element is turned on/off by the switch terminal; a first resistor having a first terminal connected to the second terminal of the switch element, a fingerprint influenced_intensity of light illuminating the first resistor so that resistance of the first resistor and a voltage level of the second terminal of the switch element change; and a second resistor having a first terminal connected to the second terminal of the switch element and the resistance of the second resistor is fixed; wherein when the switch elements are turned on, the detecting and processing circuit analyzes the fingerprint according to the voltage levels of the second terminals of the plurality switch elements.