US 12,131,572 B1
Capacitive fingerprint sensor
Xiang-Rui Chang, Hsinchu (TW); and Chao-Chien Chiu, Hsinchu (TW)
Assigned to AUO Corporation, Hsinchu (TW)
Filed by AUO Corporation, Hsinchu (TW)
Filed on Sep. 4, 2023, as Appl. No. 18/460,602.
Claims priority of application No. 112113346 (TW), filed on Apr. 10, 2023.
Int. Cl. G06V 40/13 (2022.01)
CPC G06V 40/1306 (2022.01) 5 Claims
OG exemplary drawing
 
1. A capacitive fingerprint sensor, comprising:
a plurality of capacitive sensing pixels, each of the capacitive sensing pixels comprising:
a sensing node;
a first transistor, having a first terminal receiving a first system voltage, a control terminal receiving a reset control signal, and a second terminal coupled to the sensing node;
a sensing capacitor, coupled between the sensing node and a sensing control signal; and a second transistor, having a first terminal receiving a second system voltage, a control terminal receiving a sensing voltage of the sensing node, and a second terminal providing a sensing output signal,
wherein each of the capacitive sensing pixels further comprises a current source coupled to the second terminal of the second transistor;
wherein the first transistor and the second transistor are respectively an N-type transistor;
wherein during a reset period, the reset control signal and the first system voltage are at a high voltage level, and the sensing control signal and the second system voltage are at a low voltage level.