Fingerprint Panel Light Transmittance Control for Image Accuracy
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Solution Overview
Problem
The PIN photodiode used in optical fingerprint identification devices suffers from a performance defect where charges are not quickly transferred, leading to residual charges and a lag phenomenon, resulting in reduced accuracy and precision of fingerprint images.
Innovation Solution
A panel for fingerprint identification is designed with a display unit, a unit for adjusting light transmittance, and a control unit, where the light transmittance is controlled to be less than or equal to a threshold during the display stage to prevent residual charges, and greater than the threshold during the fingerprint identification stage to enhance image accuracy, using structures with liquid crystal layers or color change layers to manage light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light transmittance is increased to enhance fingerprint image quality, then measurement precision improves, but residual charges accumulate reducing reliability
Solution Approach 1:
The patent applies dynamics by making the light transmittance of the display unit dynamically adjustable based on operational mode. During fingerprint identification, the display unit transitions to a high-transmittance state to maximize light passage and image quality. During normal display, it maintains a low-transmittance state for normal operation. This dynamic adjustment resolves the contradiction by optimizing light transmittance for each specific operational context.
Solution Approach 2:
The patent implements periodic action through time-separated operational stages. The system alternates between a display stage (where the display unit shows content with normal transmittance) and a fingerprint identification stage (where the display unit switches to high transmittance mode). This periodic switching ensures that high light transmittance is applied only when needed for fingerprint capture, preventing charge accumulation while maximizing image quality during identification.
2Reliability
If light transmittance is decreased to prevent residual charges, then reliability improves, but fingerprint image accuracy deteriorates
Solution Approach 1:
The patent applies dynamics by making the light transmittance of the display unit dynamically adjustable based on operational mode. During fingerprint identification, the display unit transitions to a high-transmittance state to maximize light passage and image quality. During normal display, it maintains a low-transmittance state for normal operation. This dynamic adjustment resolves the contradiction by optimizing light transmittance for each specific operational context.
Solution Approach 2:
The patent implements periodic action through time-separated operational stages. The system alternates between a display stage (where the display unit shows content with normal transmittance) and a fingerprint identification stage (where the display unit switches to high transmittance mode). This periodic switching ensures that high light transmittance is applied only when needed for fingerprint capture, preventing charge accumulation while maximizing image quality during identification.
3Device complexity
If a single structure is used for both display and fingerprint identification, then device complexity is reduced, but functional performance deteriorates
Solution Approach 1:
The patent applies universality by designing the display unit to perform multiple functions: it serves as both the display component and the light transmittance adjustment component for fingerprint identification. By making the display unit itself adjustable in light transmittance, the patent eliminates the need for a separate adjustable light transmittance structure, thereby reducing device complexity while maintaining multi-functional 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 improves the accuracy and precision of fingerprint images by preventing residual charges and ensuring optimal light transmission during identification, thereby enhancing the overall fingerprint identification process.
Implementation Method 1
the unit for adjusting light transmittance is configured to transmit light transmitted through the display unit, and the control unit is connected with the unit for adjusting light transmittance and is configured to control light transmittance of the unit for adjusting light transmittance
Implementation Method 2
the display unit is configured to emit first light to display an image to be displayed
Implementation Method 3
the unit for fingerprint identification is configured to receive light transmitted through the unit for adjusting light transmittance and obtain a fingerprint image according to the light transmitted through the unit for adjusting light transmittance
Data Source
AI summary
A panel for fingerprint identification and a control method thereof, and an apparatus for fingerprint identification. The panel for fingerprint identification includes: a display unit, a control unit, a unit for adjusting light transmittance and a unit for fingerprint identification which are disposed on a backlight side of the display unit, wherein an operating state of the panel for fingerprint identification includes: a display stage and a fingerprint identification stage. At the display stage, the display unit is configured to emit first light to display an image to be displayed, the unit for adjusting light transmittance is configured to transmit light transmitted through the display unit, and the control unit is connected with the unit for adjusting light transmittance and is configured to control the light transmittance of the unit for adjusting light transmittance.