Under-Display Fingerprint Pixel Driving for Longer Sensing Time
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Solution Overview
Problem
Display devices face challenges in achieving sufficient light-sensing periods and accuracy for fingerprint authentication due to insufficient light-sensing periods and accuracy of light-sensing pixels, particularly in optical fingerprint recognition systems.
Innovation Solution
The display device incorporates a display panel with light-sensing pixels that are driven with the driving frequency of image display pixels, allowing for increased light-sensing periods by resetting and driving light-sensing pixels for each horizontal line during blank periods and using multiplexers to apply reset signals, and a fingerprint scan driver to sequentially supply scan signals, enhancing light-sensing accuracy through fingerprint scan lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light-sensing pixels are driven with the driving frequency of image display pixels for high resolution, then image display quality is improved, but light-sensing period and light-sensing accuracy become insufficient
Solution Approach 1:
The patent divides the pixel array into distinct image display pixels and light-sensing pixels, with light-sensing pixels specifically dedicated to fingerprint sensing. This segmentation allows light-sensing pixels to be optimized for sensing operations independently from image display requirements, enabling sufficient light-sensing period and accuracy without compromising image quality.
Solution Approach 2:
The patent implements periodic light-sensing operations during blank periods of the display frame cycle. Light-sensing pixels perform fingerprint sensing during these idle periods when no image data needs to be displayed, creating a periodic sensing rhythm that accumulates sufficient light-sensing period while maintaining high-resolution image display during active periods.
2Speed
If light-sensing pixels are driven at high frequency for high resolution display, then display refresh rate is improved, but light-sensing period becomes insufficient
Solution Approach 1:
The patent utilizes blank periods within the display frame cycle to perform light-sensing operations periodically. During active display periods, pixels operate at high refresh rates for smooth image display, while during blank periods, light-sensing pixels accumulate sensing data, effectively extending the light-sensing period without reducing display refresh rate.
Solution Approach 2:
The patent ensures continuous useful action by utilizing every available time slot - image display pixels operate continuously during active periods, while light-sensing pixels operate continuously during blank periods. This continuous utilization of different time slots for different functions maximizes both display performance and sensing accuracy.
3Measurement precision
If reset signals are supplied to light-sensing pixels during active display period, then light-sensing accuracy is improved, but display performance is degraded
Solution Approach 1:
The patent schedules reset signal operations periodically during blank periods rather than during active display periods. This periodic timing ensures that light-sensing pixels are properly reset for accurate sensing without interrupting the continuous display refresh operation, thereby maintaining both sensing accuracy and display performance.
Solution Approach 2:
The patent performs reset operations as preliminary actions during blank periods before the next sensing or display operation begins. By resetting light-sensing pixels in advance during idle periods, the system prepares the sensing pixels for accurate measurement without interfering with ongoing display operations, ensuring both accuracy and performance.
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 increases the light-sensing period and accuracy of fingerprint recognition by sampling light-sensing data at multiple frame periods, improving the overall fingerprint sensing capability of the display device.
Implementation Method 1
The optical sensing may authenticate a user's fingerprint by sensing light reflected by a user's fingerprint
Implementation Method 2
light-sensing pixels comprising photo-detecting units in a fingerprint sensing area in the image display area
Data Source
AI summary
A display device comprises a display panel comprising an image display area and a non-display area, display pixels comprising light-emitting elements in the image display area and pixel driving units connected to the light-emitting elements, light-sensing pixels comprising photo-detecting units in a fingerprint sensing area in the image display area, and sense driving units connected to the photo-detecting units, a light-sensing reset driver configured to supply reset signals to the sense driving units of the light-sensing pixels for at least each horizontal line among the light-sensing pixels in response to a line select signal from a display driving circuit; and a fingerprint scan driver configured to sequentially supply a fingerprint scan signal to the sense driving units of the light-sensing pixels in response to a fingerprint scan control signal from the display driving circuit.