Fingerprint Sensor Synchronization with Display Dimming
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Solution Overview
Problem
Current electronic devices face reduced fingerprint detection performance due to the influence of display screen brightness changes, which affect the accuracy of ambient light detection and fingerprint image collection, especially when ambient light sensors are positioned under the display screen.
Innovation Solution
A method for fingerprint detection that synchronizes the exposure of a fingerprint sensor's pixel array with the dimming period of the display screen, ensuring a constant exposure time during both bright and dark periods, thereby fixing the position of horizontal stripes in the fingerprint image and improving detection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the display screen increases the length of the dimming period and dark light duration to improve ambient light detection accuracy, then ambient light detection accuracy is improved, but fingerprint image collection is affected and fingerprint detection performance is reduced
Solution Approach 1:
The patent applies periodic action by synchronizing the fingerprint sensor's exposure timing with the display screen's periodic dimming cycles. The sensor is configured to expose during specific phases of the dimming period (bright period or dark period), converting the periodic brightness variation into a controllable exposure rhythm that eliminates horizontal stripes while maintaining ambient light detection capability
Solution Approach 2:
The patent implements preliminary action by pre-configuring the fingerprint sensor's exposure timing based on the known dimming period parameters before actual fingerprint capture. The sensor controller pre-calculates the optimal exposure window within each dimming cycle, ensuring that exposure occurs at the most suitable moment (either during bright or dark period) to avoid stripe artifacts
2Measurement precision
If the display screen dimming period is extended to improve ambient light sensor detection, then ambient light detection is improved, but the position of horizontal stripes in fingerprint images becomes variable, making elimination difficult
Solution Approach 1:
The patent employs feedback by using the synchronization signal from the display screen to continuously adjust and lock the fingerprint sensor's exposure timing. The sensor controller receives feedback about the display's dimming state and adjusts exposure timing accordingly, ensuring that horizontal stripes consistently appear at the same position in the fingerprint image, thereby simplifying their elimination through fixed-position processing algorithms
3Productivity
If the exposure time of pixels is not synchronized with the display screen dimming period, then fingerprint image collection is continuous, but horizontal stripes appear at variable positions in the fingerprint image
Solution Approach 1:
The patent applies periodic action by aligning the fingerprint sensor's exposure rhythm with the display screen's periodic dimming cycles. By configuring the sensor to expose at specific phases of the dimming period (synchronized through the synchronization signal), the system maintains continuous fingerprint image collection capability while ensuring that horizontal stripes consistently appear at the same position, enabling stable and predictable image quality
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
This approach stabilizes the position of horizontal stripes in fingerprint images, making it easier to eliminate them using fingerprint algorithms, thus enhancing the overall performance of fingerprint detection by reducing the impact of display screen brightness changes.
Implementation Method 1
controlling a screen component of an electronic device to work, so that a fingerprint sensor perceives light signal reflected by a back plate of the screen component
Data Source
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AI summary
A method for fingerprint detection, a fingerprint sensor and an electronic device, which may more easily reduce an influence of a brightness change of a display screen on the fingerprint detection and improve performance of the fingerprint detection. The method for the fingerprint detection includes: receiving a synchronization signal of a display screen, the synchronization signal being configured to trigger a pixel array of a fingerprint sensor to expose, where a period of the synchronization signal is synchronized with a dimming period of the display screen, and the dimming period includes a bright period and a dark period (510); exposing each row of pixels in the pixel array in sequence based on triggering of the synchronization signal, so that a position of the pixel whose exposure time corresponding to the dark period in the pixel array is constant (520), where data of each row of the pixels after exposure is configured to obtain a fingerprint image.