Display Driving Circuit for Localized Fingerprint Sensing
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Solution Overview
Problem
Current electronic devices with integrated fingerprint and touch sensors face challenges in efficiently performing fingerprint sensing and identification due to high brightness requirements, which can be uncomfortable for users and prolong the sensing and identification process.
Innovation Solution
An electronic circuit is designed to drive a display panel with touch and fingerprint sensors, utilizing separate gray levels and gamma curves for different areas, allowing for efficient fingerprint sensing and identification while optimizing user comfort by adjusting brightness and reducing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the whole light source is turned on to achieve highest brightness for fingerprint sensing, then the fingerprint sensing capability is improved, but user comfort deteriorates due to high brightness discomfort
Solution Approach 1:
The display panel is divided into a first area (fingerprint sensing region) and a second area (other display region). The first area is driven with first gray levels while the second area is driven with second gray levels, allowing localized high brightness only where needed for fingerprint sensing rather than illuminating the entire display.
Solution Approach 2:
Different gray levels are applied to different areas of the display panel. The first area receives higher brightness (first gray levels) optimized for fingerprint sensing, while the second area receives lower brightness (second gray levels) for user comfort. This creates local quality differentiation to simultaneously achieve sensing precision and comfort.
2Device complexity
If the application processor controls both display driving circuit and fingerprint sensing circuit sequentially, then system complexity is reduced, but fingerprint sensing time increases
Solution Approach 1:
The display driving circuit is configured to directly control both the display panel and coordinate with the fingerprint sensing circuit. By merging the control functions and enabling direct communication between the display driving circuit and fingerprint sensing circuit, the system reduces sequential processing delays while maintaining manageable complexity through integrated control.
Data Source
AI summary
An electronic circuit adapted to drive a display panel is provided. The electronic circuit includes a touch sensing circuit, a fingerprint sensing circuit and a display driving circuit. The touch sensing circuit senses a touch of a finger and determines a first area corresponding to the touch on the display panel. The fingerprint sensing circuit senses a fingerprint image of the finger corresponding to the first area. The display driving circuit drives pixels of the first area with respective first gray levels and pixels of a second area outside the first area with respective second gray levels. The display driving circuit processes respective third gray levels to obtain the respective first gray levels or the respective second gray levels. The display driving circuit generates gamma voltages corresponding to the respective first gray levels and the respective second gray levels according to a same gamma curve.