A fingerprint recognition sensor

Abstract

The invention discloses a fingerprint identification sensor and a fingerprint identification method, which include a fingerprint image sensing array for detecting finger touch, including a plurality of driving electrodes and sensing electrodes arranged in an appropriate manner, and a processor, which Cooperate with the sensing array, scan the sensing array and generate a complete fingerprint image based on the sensing signal, which generates different modulation signals and applies them to multiple driving electrodes to obtain a composite signal, and uses the modulation signal to Sensing signals of the sensing electrodes are demodulated to obtain electrical sensing signals indicating fingerprint information, and a complete fingerprint image is generated by processing the sensing signals. The invention effectively reduces the number of pins of the processor circuit chip package through the multiplexing of the electrodes, reduces the crosstalk and coupling between the sensing signals of the sensing electrodes, and optimizes the system design.

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 the electrodes may cause the quality of the fingerprint image to deteriorate or even fail. Therefore, the sensing electrode Rx must be shielded and optimized to avoid interference from other signals

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