Optical Texture Recognition With Collimated Backlight for Crosstalk Control
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Solution Overview
Problem
Optical fingerprint acquisition technologies face challenges in accurately identifying fingerprints due to light crosstalk caused by large-angle incident light, leading to reduced recognition accuracy.
Innovation Solution
A texture recognition device employs a light constraint element, such as a collimating film, to control the divergence angle of backlight within a preset range, combined with a photosensitive element to detect the reflected texture image, thereby reducing light crosstalk and improving recognition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If large-angle incident light is used for fingerprint acquisition, then the coverage area is increased, but light crosstalk occurs causing reduced recognition accuracy
Solution Approach 1:
The collimating film introduces directional control locally at the light source level, creating small-angle incident light regions that prevent crosstalk while maintaining overall coverage through the optical system design
Solution Approach 2:
The collimating film acts as an intermediary element between the backlight and fingerprint surface, modifying the light angular distribution to eliminate crosstalk while preserving coverage area
2Measurement precision
If small-angle incident light is used for fingerprint acquisition, then recognition accuracy is improved, but the coverage area is reduced
Solution Approach 1:
The optical system uses multiple layers (collimating film, light guide plate, diffuser) to control light in multiple dimensions, achieving both small incident angles and wide coverage through spatial light distribution management
3Measurement precision
If collimating film with hollowed-out regions is used to constrain light divergence angle, then light crosstalk is reduced, but device complexity increases
Solution Approach 1:
The collimating film is implemented as a thin flexible film with hollowed-out regions, providing precise light angular control without adding significant structural complexity or thickness to the device assembly
Solution Approach 2:
The collimating film divides the light path into multiple discrete hollowed-out regions, each controlling specific angular ranges, which simplifies the overall optical design while achieving precise crosstalk elimination
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 device effectively prevents light crosstalk during texture recognition, enhancing the accuracy of fingerprint identification by ensuring that the backlight divergence angle remains within a specified range, thus improving the contrast and precision of texture image detection.
Implementation Method 1
a light constraint element, configured to perform a light divergence angle constraint process on the first backlight to obtain second backlight with a divergence angle within a preset angle range
Implementation Method 2
a photosensitive element, configured to detect the second backlight reflected by a texture of the detection object to recognize a texture image of the texture of the detection object
Data Source
AI summary
A texture recognition device and a display device are provided. The texture recognition device includes a backlight element, configured to provide first backlight; a light constraint element, configured to perform a light divergence angle constraint process on the first backlight to obtain second backlight with a divergence angle within a preset angle range, the second backlight being transmitted to a detection object; and a photosensitive element, configured to detect the second backlight reflected by a texture of the detection object to recognize a texture image of the texture of the detection object.