Optical Fingerprint Sensor Light Source Power Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical fingerprint recognition faces challenges in obtaining accurate fingerprint images due to small differences in reflected light, which are often obscured by interference signals from the display panel's internal structure.
Innovation Solution
A method is introduced to set light sources in a display panel for optical fingerprint recognition, where initial light source settings are adjusted to minimize or optimize interference signals by varying the power of light sources based on color and position, allowing for robust fingerprint image restoration and efficient recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uniform power is applied to all light sources in the fingerprint recognition window, then the display panel structure is simple and easy to manufacture, but interference signals from the internal structure obscure the fingerprint image and reduce recognition accuracy
Solution Approach 1:
The patent applies local quality by dividing the fingerprint recognition window into multiple regions and assigning different power levels to light sources in different regions. Specifically, light sources are classified into first, second, and third groups with different power values, allowing localized optimization of light emission to reduce interference signals from specific areas of the display panel while maintaining overall system functionality.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the power parameter of individual light sources based on their position and color characteristics. The controller sets different power values for light sources of different colors (e.g., red, green, blue) and different positions within the fingerprint recognition window, thereby optimizing the optical properties to minimize interference signals and enhance fingerprint image quality.
2Reliability
If light source powers are varied by color and position to minimize interference signals, then fingerprint recognition accuracy improves, but the control system becomes more complex and requires additional calibration
Solution Approach 1:
The patent applies preliminary action by performing calibration operations before actual fingerprint recognition. The controller pre-determines the optimal power settings for each light source based on its color and position, storing these settings in advance. This preliminary configuration eliminates the need for complex real-time adjustments during fingerprint recognition, simplifying the user operation while maintaining high reliability.
Solution Approach 2:
The patent implements feedback mechanisms through calibration processes that measure the actual interference signals produced by each light source and adjust the power settings accordingly. The system uses the captured calibration data to optimize light source parameters, creating a closed-loop control system that automatically compensates for variations in display panel structure and environmental conditions.
3Measurement precision
If all light sources are driven at maximum power to enhance signal strength, then the fingerprint image signal is stronger, but the interference signals from the display panel internal structure also increase
Solution Approach 1:
The patent applies parameter changes by optimizing the power parameter of each light source individually rather than using a uniform maximum power setting. By adjusting the power of each light source according to its specific position and color characteristics, the system enhances the reflected light signal from the fingerprint while simultaneously minimizing the interference signals generated by the display panel's internal structure at each location.
Solution Approach 2:
The patent implements local quality by applying different power levels to light sources in different regions of the fingerprint recognition window. Areas with higher interference signals receive lower power settings, while areas with lower interference receive higher power, thereby optimizing the signal-to-interference ratio locally across the entire recognition window.
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 enables accurate fingerprint recognition by reducing interference signals, even under changes caused by temperature and pressure, thereby enhancing the reliability and efficiency of optical fingerprint recognition.
Implementation Method 1
obtaining initial calibration data based on reflected light of an object received by a fingerprint recognition sensor through the fingerprint recognition window
Implementation Method 2
driving a portion of light sources among a plurality of light sources included in the display panel
Data Source
AI summary
A method of setting light sources in a display panel for optical fingerprint recognition is provided. The method includes driving a portion of light sources disposed to correspond to a fingerprint recognition window which is a partial region of a display panel based on initial light source setting values, obtaining initial calibration data based on reflected light of an object received by a fingerprint recognition sensor through the fingerprint recognition window while driving the portion of the light sources; and determining final light source setting values such that powers for driving light sources of different colors among the portion of the light sources are different, the final light source setting values being determined to minimize contrast of an interference signal included in the initial calibration data.