Fingerprint recognition sensor

Abstract

The invention discloses a fingerprint recognition sensor and a fingerprint recognition method. The fingerprint recognition sensor comprises a fingerprint image sensing array and a processor, wherein the fingerprint image sensing array is used for detecting finger touch and comprises multiple driving electrodes and multiple induction electrodes, the driving electrodes and the induction electrodes are arranged appropriately, and the processor is matched with the sensing array, scans the sensing array and generates complete fingerprint images on the basis of sensing signals. The fingerprint recognition sensor generates different modulation signals, and the different modulation signals are applied to the driving electrode so that synthetic signals can be obtained. Demodulation is carried out on the sensing signals of the induction electrodes through the modulation signals, so that electrical inductive signals of fingerprint information are obtained. Complete fingerprint recognition images are generated through processing on the inductive signals. According to the fingerprint recognition sensor, the number of encapsulated pins of processor circuit chips is effectively reduced through reusing of the electrodes, crosstalk and coupling among the sensing signals of the electrodes are reduced, and system design is optimized.

Description

technical field [0001] The invention relates to a fingerprint identification sensor, which is integrated in a capacitive touch screen or a touch device, and obtains fingerprint information by detecting changes in mutual capacitance values ​​of electrodes caused by finger touch. Background technique [0002] The basic sensing principle of capacitive fingerprint recognition sensor is as follows: figure 1 As shown, the fingerprint information is obtained by detecting the capacitance between the sensor electrodes. Such as figure 1 As shown, a planar capacitance is formed between two electrodes S1 and S2, and the electrodes are usually formed in a transparent substrate. When a finger touches the substrate in the sensing area, the fingerprint ridge or fingerprint valley touches between the electrodes S1 and S2, which will change the dielectric constant of the medium, thereby changing the size of the plane capacitance between the electrodes. The detection chip converts the capac...

AI Technical Summary

Problems solved by technology

This makes the fingerprint identification detection chip also need 160 Tx drive pins, too many chip pins will bring difficulties in packaging and wiring, and make the chip area restricted by the chip pins

[0004] In addition, because the change in sensing capacitance of the fingerprint recognition sensor is very small, the crosstalk and coupling between electrodes may cause the quality of the fingerprint recognition image to degrade or even fail. Therefore, the sensing electrode Rx must be shielded and optimized to avoid interference from other signals

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