Fingerprint Identification Substrate With Directional Light Filtration
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Solution Overview
Problem
In point light source technology for fingerprint identification, the partial overlap of imaging regions from two point light sources leads to a lag problem, affecting the imaging effect and accuracy of fingerprint identification due to residual electric signals.
Innovation Solution
A fingerprint identification substrate with independent first and second photosensitive sensors, where the second sensor has a light filtration structure allowing light only in a specific direction, and a larger photosensitive area for the first sensor to minimize lag effects, enabling accurate fingerprint identification by determining the residual electric signal and fingerprint electric signal through a mapping relationship.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two point light sources are used to realize complementary imaging, then the complete fingerprint image can be obtained, but the imaging regions of the two point light sources partially overlap each other causing lag problem
Solution Approach 1:
The photosensitive sensor is divided into multiple independent photosensitive units, each corresponding to a specific point light source. Each photosensitive unit contains only one photosensitive sensor that responds to its corresponding point light source, preventing cross-interference and lag effects from overlapping imaging regions.
Solution Approach 2:
A light filtration structure (including quarter-wave plate and linear polarizer) is introduced as an intermediary between the point light source and the photosensitive sensor. This intermediary ensures that only light in the first direction (perpendicular to the base substrate) can reach the photosensitive sensor, blocking oblique light and eliminating the lag problem caused by overlapping imaging regions.
2Productivity
If the first point light source is enabled, then light from the first point light source directly reaches the photosensitive sensor, but when the second point light source is enabled, a strong lag will remain in the imaging region
Solution Approach 1:
The photosensitive sensor is segmented into multiple independent photosensitive units, each dedicated to a specific point light source. This segmentation ensures that when one point light source is enabled, only its corresponding photosensitive unit is activated, preventing lag effects from affecting other regions.
Solution Approach 2:
The light filtration structure acts as an intermediary that allows only light traveling perpendicular to the base substrate to reach the photosensitive sensor. This eliminates oblique light paths that cause lag, ensuring that each point light source only affects its designated photosensitive unit without causing residual effects.
3Reliability
If a light filtration structure is arranged at the second photosensitive sensor, then only light in the first direction can pass through, but the device complexity increases
Solution Approach 1:
The light filtration structure serves multiple functions simultaneously: it filters oblique light to eliminate lag effects, defines the imaging region boundary, and ensures that only perpendicular light reaches the photosensitive sensor. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The light filtration structure comprises multiple optical components (quarter-wave plate and linear polarizer) laminated together to form a composite structure. This composite design achieves superior light filtering performance while maintaining a compact form factor, balancing functionality with structural efficiency.
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 solution ensures improved imaging effects and accuracy in fingerprint identification by eliminating the lag caused by residual electric signals, allowing for effective fingerprint recognition.
Implementation Method 1
a light filtration structure arranged at a side of the second photosensitive sensor facing the point light source and configured to merely allow light in a first direction to pass therethrough, and the first direction is perpendicular to the base substrate
Implementation Method 2
at least one photosensitive unit arranged at a side of the base substrate away from the point light source, and configured to receive the signal light reflected by a finger and identify a fingerprint
Data Source
AI summary
The present disclosure relates to the field of fingerprint identification technology, and provides a fingerprint identification substrate, a fingerprint identification method and a display device. The fingerprint identification substrate includes: a base substrate; at least one point light source arranged on the base substrate and configured to emit signal light; and at least one photosensitive unit arranged at a side of the base substrate away from the point light source, and configured to receive the signal light reflected by a finger and identify a fingerprint. Each photosensitive unit includes a first photosensitive sensor and a second photosensitive sensor independent of each other, a light filtration structure is arranged at a side of the second photosensitive sensor facing the point light source and configured to merely allow light in a first direction to pass therethrough, and the first direction is perpendicular to the base substrate.