In-Display Fingerprint Sensor Voltage Reset Circuit
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Solution Overview
Problem
The integration of optical fingerprint sensors in touch display panels leads to unstable fingerprint image quality, resulting in high false rejection and false acceptance rates in fingerprint recognition systems.
Innovation Solution
A fingerprint sensing apparatus and readout circuit that includes a reset period before the fingerprint sensing cycle to reset the voltage of the fingerprint sensors, improving image stability and reducing false rejection and false acceptance rates by initializing the voltage to a different initial voltage during the initialization period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If optical fingerprint sensors are integrated in touch display panels, then device size is reduced and convenience is increased, but fingerprint image quality becomes unstable
Solution Approach 1:
The patent applies preliminary action by implementing a reset period before the fingerprint sensing cycle to reset the voltage of the reset node to a first voltage. This preliminary voltage reset stabilizes the operating conditions of the fingerprint sensor before actual sensing begins, thereby improving image quality stability while maintaining the in-display integration
2Adaptability or versatility
If in-display fingerprint sensor structure is used, then integration is improved, but false rejection rate and false acceptance rate increase
Solution Approach 1:
The patent implements preliminary action through an initialization period that sets the voltage of the reset node to a specific initial voltage before the sensing cycle. This preliminary voltage initialization ensures consistent starting conditions for each sensing operation, reducing measurement errors and improving recognition accuracy while maintaining in-display integration
Solution Approach 2:
The patent applies periodic action by implementing a structured fingerprint sensing cycle that repeatedly alternates between reset period, initialization period, and sensing period. This periodic voltage management ensures consistent operating conditions with each cycle, reducing false rejection and false acceptance rates while maintaining high integration
Data Source
AI summary
A fingerprint sensing apparatus includes a plurality of fingerprint sensors and a fingerprint readout circuit. The fingerprint sensors may be configured to operate in a fingerprint sensing cycle. The fingerprint readout circuit may be coupled to the plurality of fingerprint sensors via a plurality of sensing lines. The fingerprint readout circuit may be configured to control the fingerprint sensors to operate in the fingerprint sensing cycle. The fingerprint sensing cycle includes an initialization period, an exposure period and a readout period. A voltage of a reset node in each fingerprint sensor among the fingerprint sensors is reset to a first voltage in a reset period before the fingerprint sensing cycle starts. The voltage of the reset node in each fingerprint sensor is initialized to an initial voltage in the initialization period. The initial voltage is different from the first voltage.