Capacitive fingerprint sensor

一种指纹传感器、传感器的技术，应用在获取/整理指纹/掌纹、仪器、电子开关等方向，能够解决传感器成像模糊、电容衰减等问题

Active Publication Date: 2016-02-17
GUANGZHOU GUOTONGXIN MICROELECTRONICS CO LTD
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

When the dielectric layer between the sensing electrode array and the finger is thicker, the capacitance will attenuate and the image of the sensor will be blurred.

Method used

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Embodiment Construction

[0100] The present invention will be further described below in conjunction with specific examples. Furthermore, repeated reference numerals or designations may be used in different embodiments. These repetitions are only for the purpose of simply and clearly describing the present invention, and do not represent any relationship between the different embodiments and / or structures discussed.

[0101] figure 1 A schematic diagram of a capacitive fingerprint sensor. Such as figure 1 As shown, the fingerprint sensor proposed by the present invention mainly includes a sensing unit (1), a charge accumulating unit (3), a comparison circuit (4), a sensor ground generator (5), and a bus capacitor (2). The sensing units (1) usually appear in groups.

[0102] The output terminal of the sensing unit (1) is connected to the input terminal of the charge accumulation unit (3); the input terminal of the charge accumulation unit (3) is connected to the output terminal of the sensing unit ...

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Abstract

The invention provides a capacitive fingerprint sensor. According to the capacitive fingerprint sensor, fingerprints are imaged by measuring the difference of coupling capacitance formed between fingerprint valley lines and corresponding units on a planar sensing electrode array and coupling capacitance formed between fingerprint ridge lines and corresponding units on the planar sensing electrode array. The C-Q-T type capacitive fingerprint sensor measures the capacitance indirectly through conversion from capacitance to charge quantity and conversion from charge quantity to integral time; the efficiency of conversion from capacitance to charge quantity can be improved by coupling drive signals to a human body, and therefore the sensitivity of the sensor is improved. According to the improved C-Q-T type capacitive fingerprint sensor, the inverse drive signals coupled with the ground potential of the fingerprint sensor are used for equivalently replacing drive signals coupled with the human body, and therefore the sensitivity of the sensor is further improved.

Description

technical field [0001] The invention relates to a capacitive fingerprint sensor. Background technique [0002] The capacitive fingerprint sensor technical solution proposed in the Chinese invention patent "Capacitive Fingerprint Sensor" (application number 201410004072.3) is based on the Chinese invention patent "Capacitive Distance Sensor" (application number 201210403271.2) to the sensing equation and circuit model. After optimization, a new circuit structure was proposed, and the "C-Q-T" conversion was successfully realized. [0003] The capacitive fingerprint sensor images the fingerprint by measuring the size difference of the coupling capacitance formed between the fingerprint valley line, the ridge line and the planar sensing electrode array unit. When the dielectric layer between the sensing electrode array and the finger is thicker, the capacitance will attenuate, and the image of the sensor will be blurred. Due to the development of technology, the thickness of t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/00
CPCG06V40/1306G06F18/00H03K17/962H03K2017/9604
Inventor 许科峰李扬渊
Owner GUANGZHOU GUOTONGXIN MICROELECTRONICS CO LTD
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