Biometric Detection in Display Panels Using Sequential Light Penetration
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Solution Overview
Problem
Fingerprint recognition technologies face interference from undesired reflected light, which affects signal quality and accuracy in optical fingerprint recognition systems.
Innovation Solution
A display device with a biometric detecting area that uses a backlight module to sequentially penetrate specific pixels during a blanking period, employing photodetectors to differentiate between desired and undesired light, thereby minimizing signal interference and enhancing biometric pattern detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical fingerprint recognition technology emits light onto a finger and receives reflected light, then a fingerprint image can be constructed, but undesired reflected light causes signal interference and reduces detection accuracy
Solution Approach 1:
The display panel is divided into distinct regions: display regions with pixels for normal display function, and a biometric detecting area with photodetectors for fingerprint sensing. This segmentation allows separate optimization of display and sensing functions, enabling the photodetectors to specifically detect reflected light from the finger while ignoring other light sources.
Solution Approach 2:
The harmful factor of undesired reflected light is addressed by extracting and isolating the desired signal. The patent uses photodetectors positioned adjacent to pixels to specifically capture the reflected light from the finger, separating this useful signal from other ambient or display-related light that would cause interference.
2Ease of operation
If the display panel uses pixels for display during active period, then display function is maintained, but light from pixels interferes with biometric detection
Solution Approach 1:
The display device operates in periodic cycles with distinct phases: during the active display period, pixels emit light for normal display function; during the blanking period, the display function is suspended and photodetectors are activated to detect reflected light from the finger. This periodic switching eliminates interference by ensuring that pixel light emission and biometric detection do not occur simultaneously.
Solution Approach 2:
The biometric detection is performed during the blanking period, which occurs before the next active display period begins. This timing allows the system to complete the sensing operation in advance, using the otherwise unused blanking period to gather biometric data without interfering with the upcoming display cycle.
3Measurement precision
If photodetectors are positioned adjacent to pixels, then desired reflected light can be detected, but device structure becomes more complex
Solution Approach 1:
The display function and biometric sensing function are merged into a single integrated display panel structure. Pixels and photodetectors are positioned adjacent to each other within the same panel, allowing both functions to coexist in a unified device rather than requiring separate components. This merging reduces overall system complexity despite the increased density of elements.
Solution Approach 2:
The display panel serves multiple functions: during the active period, pixels provide display output; during the blanking period, the same panel structure enables biometric detection through adjacent photodetectors. This multi-functionality allows a single device to perform both display and fingerprint recognition, reducing the need for additional separate components.
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
The solution effectively reduces signal interference, allowing for the construction of clear biometric patterns by isolating desired light and eliminating unwanted reflections, thereby improving the accuracy of biometric detection.
Implementation Method 1
The biometric detecting area has plural blocks and each of the blocks comprises plural first pixels and plural photodetectors adjacent to the first pixels, respectively. The light sequentially penetrates the first pixels within each of the blocks in the blanking period of the display device.
Data Source
AI summary
A display device is provided. The display device includes a display panel having a biometric detecting area configured to detect a biometric pattern of a biometric object in a blanking period of the display device. The biometric detecting area has plural blocks and each of the blocks comprises plural first pixels and plural photodetectors adjacent to the first pixels, respectively. The light sequentially penetrates the first pixels within each of the blocks in the blanking period of the display device.