Time-division photo-sensing fingerprint detection with segmented light emission
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Solution Overview
Problem
Current fingerprint recognition technologies using total reflection and capacitance methods face challenges in accurately differentiating ridge and valley lines due to diffused light and residual images, leading to blurred images and inaccurate detection.
Innovation Solution
A photo-sensing detection apparatus operating in a time-division mode with multiple time-sequential photo-sensing modes, utilizing non-overlapping light emitting and sensing sub-regions to optimize contrast and reduce diffused light interference, and integrating signals across modes to detect complete fingerprint information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If total reflection method is used for fingerprint recognition, then light reflection from finger ridges and valleys can be detected, but diffused light causes blurred images and reduces detection accuracy
Solution Approach 1:
The sensing area is divided into multiple independently controllable light emitting blocks and sensing sub-regions. By selectively activating specific blocks and regions, the system can isolate and eliminate diffused light from areas outside the intended sensing zone, thereby improving fingerprint detection accuracy while reducing light interference.
Solution Approach 2:
Different regions of the display panel are assigned different functions: some regions emit light for illumination, while specific sensing sub-regions detect reflected light. This local differentiation allows the system to optimize light emission and detection in specific areas, reducing the impact of diffused light from other regions and enhancing measurement precision.
2Loss of information
If multiple light emitting blocks are activated simultaneously to cover the entire fingerprint area, then complete fingerprint information can be captured, but diffused light from adjacent blocks increases noise and reduces signal-to-noise ratio
Solution Approach 1:
Light emitting blocks are activated sequentially in different time slots rather than simultaneously. Each block illuminates a specific region during its designated time slot, and the corresponding sensing sub-region detects the reflected light. This periodic activation ensures that only light from the currently active block is detected, eliminating diffused light noise from other blocks while capturing complete fingerprint information across all time slots.
Solution Approach 2:
The system dynamically switches between different light emitting blocks and their corresponding sensing sub-regions based on the detection requirements. By adaptively activating only the necessary blocks at any given time and integrating signals from multiple time-sequential modes, the system achieves both complete information capture and noise reduction.
3Area of stationary object
If the entire display panel is used for light emission and detection, then full coverage fingerprint sensing is achieved, but residual images from previous frames reduce detection accuracy
Solution Approach 1:
The display panel is segmented into multiple light emitting blocks that can be activated independently in different time slots. By dividing the sensing process into discrete temporal and spatial segments, the system captures fingerprint information from different regions sequentially rather than simultaneously, thereby eliminating residual image interference while maintaining full coverage sensing capability.
Solution Approach 2:
The system continuously scans the fingerprint area by sequentially activating different light emitting blocks and their corresponding sensing sub-regions. This continuous time-sequential scanning ensures that complete fingerprint information is captured across the entire display panel area while minimizing the impact of residual images from previous frames through temporal separation.
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
Enhances signal-to-noise ratio and accuracy of fingerprint recognition by optimizing light emission and detection patterns, reducing the impact of diffused light and residual images, resulting in clearer and more accurate fingerprint detection.
Implementation Method 1
at least a portion of the light being totally reflected by a surface of the counter substrate away from the array substrate
Implementation Method 2
a photosensor configured to detect the at least the portion of the light being totally reflected by the surface of the counter substrate away from the array substrate
Data Source
AI summary
A photo-sensing detection apparatus is provided. The photo-sensing detection apparatus includes a counter substrate; an array substrate facing the counter substrate; and a fingerprint sensing driver. The array substrate includes a plurality of light sources configured to emit light toward the counter substrate, at least a portion of the light being totally reflected by a surface of the counter substrate away from the array substrate; and a photosensor configured to detect the at least the portion of the light being totally reflected by the surface of the counter substrate away from the array substrate. The photo-sensing detection apparatus is configured to be operated in a time-division mode including a plurality of time-sequential photo-sensing modes. The fingerprint sensing driver is configured to detect a fingerprint information by integrating signals detected in the plurality of time-sequential photo-sensing modes.