Radio-frequency micro-capacitance fingerprint acquisition chip and method

Abstract

The invention discloses a radio-frequency micro-capacitance fingerprint acquisition chip and method. The chip comprises a plurality of reference sensing units, a two-dimensional sensing unit array formed by the reference sensing units, an insulating layer, an insulating substrate serving as a finger contact surface, a radio-frequency signal generation circuit, a radio-frequency drive electrode, a sensing unit array controller used for providing bias-power-supply switching signals for switching on or switching off the sensing units and charge-discharge sequence signals needed by the sensing units, an analog-digital conversion array, a digital-analog converter for controlling the gain of the analog-digital conversion array, a sensing unit offset correction circuit, a fingerprint image cache, a fingerprint image output controller and an image signal processor. Due to the improvement of the structure of the sensing units and the additional arrangement of the sensing unit offset correction circuit, the radio-frequency micro-capacitance fingerprint acquisition chip can solve the problems of fingerprint residual, interference caused by other radiofrequency radiation, false fingers and small detection depth; besides, the chip can be embedded into a capacitive touch screen.

Description

technical field [0001] The invention relates to the field of integrated circuit design, in particular to a radio frequency microcapacitor fingerprint collection chip and a collection method thereof. Background technique [0002] As people's requirements for information security are getting higher and higher, living biometric authentication and identification are more and more used in people's daily life. Fingerprint authentication has high reliability and cost-effectiveness in biometric authentication, and has become the mainstream of current biometric authentication. At the same time, fingerprint collection technology is also developing rapidly. A fingerprint sensor with lower cost, faster speed, small size, low power consumption, high dynamic range and high detection depth will occupy a huge market. Therefore, the fingerprint sensor with the above advantages Fingerprint sensors have become the focus of current research, and capacitive fingerprint sensors have become one o...

AI Technical Summary

Problems solved by technology

[0009] Therefore, existing fingerprint sensors, no matter capacitive or radio-frequency fingerprint sensors, detect the valley-ridge capacitance difference formed by finger valleys, ridges and sensor sensing electrodes. For existing domestic fingerprint sensors, it is possible to detect The valley ridge capacitance difference is at the order of several fF. For the existing foreign fingerprint sensors, the valley ridge capacitance difference that can be detected is at the order of 0.1fF. The existing domestic and foreign fingerprint sensors cannot meet the special requirements of mobile devices.

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