UDFPS Luminance Compensation With Variable Refresh Control
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Solution Overview
Problem
Biometric authentication using under-display fingerprint sensors (UDFPS) is often delayed due to sub-optimal illumination of user input, caused by gradual luminosity increase in high-luminance regions, leading to inefficient fingerprint image capturing and authentication.
Innovation Solution
Implementing variable refresh rate control and display luminance compensation by adjusting luminance settings and refresh rates for high-luminance regions to ensure consistent and stable illumination during fingerprint image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the display luminance is increased to illuminate the finger for UDFPS sensing, then the illumination quality improves, but the authentication latency increases due to gradual luminosity increase
Solution Approach 1:
The system pre-warms the display luminance to a predetermined value before fingerprint image capture begins. This preliminary action ensures that when the actual capture starts, the display is already at the required luminance level, eliminating the delay that would otherwise occur during capture. The processor controls the display to gradually increase luminance to a target value before the UDFPS sensing operation commences.
Solution Approach 2:
The system dynamically adjusts the display refresh rate based on the operational phase. During the pre-warm phase, a first refresh rate is used, and during the actual fingerprint capture phase, a second (different) refresh rate is applied. This dynamic adaptation allows optimization of both the pre-heating efficiency and the capture quality, resolving the contradiction between achieving sufficient luminance and minimizing authentication time.
2Speed
If the display refresh rate is increased to improve illumination response, then the illumination speed improves, but the power consumption increases
Solution Approach 1:
The system dynamically changes the display refresh rate according to the operational phase. During pre-warming, one refresh rate is used, and during actual fingerprint capture, another refresh rate is applied. This allows the system to achieve fast illumination response when needed while conserving power during other phases, resolving the contradiction between speed and energy consumption.
Solution Approach 2:
The system changes the refresh rate parameter adaptively based on operational requirements. By adjusting this key parameter, the system optimizes the balance between illumination response speed and power consumption, using higher refresh rates only when necessary for quality capture and lower rates otherwise to save energy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates rapid and effective fingerprint authentication by ensuring well-illuminated user input capture, reducing authentication latency and improving user experience.
Implementation Method 1
Each of the pixel circuits include one or more light-emitting diodes configured to illuminate
Implementation Method 2
The emission control-line driver is configured to supply, in an alternating fashion, a low emission-control signal and a high emission-control signal to each of the pixel circuits effective to implement a refresh rate
Implementation Method 3
The data-line driver is configured to selectively supply data-line signals to one or more of the pixel circuits. The data-line signals include voltage data effective to cause one or more pixel circuits to illuminate light at varying luminosities
Data Source
AI summary
This document describes systems and techniques directed at expediting fingerprint authentication via variable refresh rate control and display luminance compensation. In aspects, a computing device having an under-display fingerprint sensor (UDFPS) and a touch-sensitive display includes a biometric authentication manager. Upon detecting at least one finger at or near the touch-sensitive display, the biometric authentication manager implements variable display refresh rates and selectively adjusts luminance settings for a high-luminance region of the touch-sensitive display for predetermined intervals. In so doing, at least one finger can be well-illuminated during UDFPS image capturing, facilitating UDFPS sensing and expediting fingerprint authentication.