Fingerprint Identification Module Using Point Light Source Array
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Solution Overview
Problem
Current fingerprint identification methods, particularly capacitive and ultrasonic types, face challenges in the display area due to interference from mediums and distance issues, while optical methods struggle with light interference from valleys and ridges when using planar light sources.
Innovation Solution
A fingerprint identification module utilizing an array substrate with a point light source array and photosensors to emit light at different times and regions, preventing light interference and improving accuracy by forming images from intensity variations, integrated into a display apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a planar light source is used for optical fingerprint identification, then the light can cover a large area, but the light reflected by valleys and ridges interferes with each other reducing identification accuracy
Solution Approach 1:
The patent divides the single planar light source into multiple point light sources arranged in an array. Each point light source illuminates a specific region, and the reflected light from valleys and ridges does not interfere with adjacent regions. This segmentation resolves the contradiction by maintaining area coverage through multiple sources while eliminating light interference that reduces measurement precision.
Solution Approach 2:
The patent introduces a microlens array as an intermediary component between the point light sources and the finger. Each microlens focuses light from its corresponding point source onto a specific region, creating precise illumination patterns. This intermediary enables controlled light distribution that covers the required area while preventing reflected light interference, thus resolving the accuracy issue.
2Area of stationary object
If the sensor and finger are placed far apart, then the module can be integrated into the display area, but the light reflected by valleys and ridges may interfere with each other
Solution Approach 1:
By segmenting the illumination into multiple point sources with controlled emission directions, the system can operate at larger distances while maintaining precision. Each point source creates a localized illumination pattern that prevents cross-interference even when the sensor-finger distance increases for display area integration.
Solution Approach 2:
The patent applies local quality by making different regions have different optical characteristics. Each point light source and its corresponding microlens create a localized optical path optimized for that specific region. This allows the system to maintain high measurement precision in each local area while the overall system is integrated into the display area with appropriate spacing.
3Measurement precision
If a thick cover layer is cut open to reduce distance between finger and sensor, then fingerprint identification accuracy improves, but the device structure becomes complex and manufacturing difficulty increases
Solution Approach 1:
The patent replaces the mechanical approach of cutting open the cover layer with an optical solution using point light sources and microlenses. Instead of physically modifying the cover layer structure to reduce distance, the system uses optimized optical paths that achieve high precision fingerprint identification while maintaining the integrity and simplicity of the original cover layer structure, thus reducing device complexity and manufacturing difficulty.
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 fingerprint identification efficiency and accuracy by reducing light interference and integrating the module into the display area, allowing for clear identification regardless of distance and improving integration and volume reduction.
Implementation Method 1
the photosensor is configured to receive the light reflected to identify fingerprint
Data Source
AI summary
A fingerprint identification module may include an array substrate (201), a plurality of point light sources (202) on the array substrate (201), and a plurality of photosensors (203) on the array substrate (201). The array substrate (201) may include a switch array (204) and a light emitting unit array (205) on the switch array (204). The plurality of point light sources (202) is configured to emit light to irradiate different regions of a finger at different times.