Patent ID: 9721140
Date: 2017-08-01
CPC Classifications: G06K

Claim:
1. A sensing method of a fingerprint sensor, the sensing method being used for sensing a capacitance between an electrode plate to be measured of the fingerprint sensor and a finger, the sensing method comprising: (a) applying a first voltage to a first node connected to the electrode plate to be measured, applying a second voltage different from the first voltage to a second node disconnected from the first node, and applying a third voltage to a conductor adjacent to the electrode plate to be measured; (b) providing a first finger drive voltage for the finger; (c) stopping applying the first voltage, the second voltage and the third voltage to the first node, the second node and the conductor respectively; (d) after step (c), applying a fourth voltage different from the third voltage to the conductor, and connecting the first node to the second node; (e) after steps (b) and (c), providing a second finger drive voltage different from the first finger drive voltage for the finger; and (f) after steps (d) and (e), obtaining a measurement result of the electrode plate to be measured according to a signal on the second node; wherein the first voltage is greater than the second voltage, the third voltage is greater than the fourth voltage, and the first finger drive voltage is less than the second finger drive voltage; or the first voltage is less than the second voltage, the third voltage is less than the fourth voltage, and the first finger drive voltage is greater than the second finger drive voltage.