Optical Sensor Structure for Ambient Light Filtering in Fingerprint Displays
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Solution Overview
Problem
Existing optical sensors face challenges in filtering ambient light effectively, leading to a low signal-to-noise ratio in fingerprint recognition, and the manufacturing of small-sized micro-lenses is difficult and costly, making large-scale production impractical.
Innovation Solution
An optical sensor design featuring a base substrate with photosensitive devices and light converged elements, where a light constrained structure with obliquely arranged optical channels directs incident light within a specific angle range to the photosensitive devices, filtering out ambient light and improving fingerprint recognition accuracy, while using a large-sized light converged element to reduce manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small-sized micro-lenses are used for light convergence, then the sensor size and complexity are reduced, but the manufacturing difficulty and cost increase significantly
Solution Approach 1:
The patent replaces expensive, difficult-to-manufacture micro-lenses with simple resin materials that can be easily integrated using existing manufacturing processes. This substitution uses inexpensive materials and methods that are already established in the industry, eliminating the need for complex micro-lens fabrication while achieving the same light convergence function.
Solution Approach 2:
The patent changes the material parameter from precision-manufactured micro-lenses to resin materials, and introduces a specific structural parameter (the light constrained structure with oblique arrangement) to compensate for the reduced optical precision. This parameter change allows the system to maintain performance while dramatically simplifying manufacturing.
2Length of moving object
If resin materials are used to integrate multi-layer diaphragms and micro-lenses, then the thickness and volume are reduced, but the adhesion and reliability of the collimation film deteriorate
Solution Approach 1:
The patent extracts the problematic multi-layer diaphragm and micro-lens integration from the system and replaces it with a simplified resin-based light constrained structure. By removing the complex layered assembly, the patent eliminates the adhesion issues between layers while maintaining the light convergence function through the oblique optical channel design.
Solution Approach 2:
The patent segments the light constrained structure into multiple diaphragm layers with oblique arrangements, where each layer is independently structured to prevent adhesion problems. The staggered opening arrangement across layers creates distinct functional zones that maintain reliability while achieving thin profile.
3Device complexity
If conventional light filtering is used, then the structure is simple, but the signal-to-noise ratio in fingerprint recognition is low due to ineffective ambient light filtering
Solution Approach 1:
The patent uses a composite structure combining multiple diaphragm layers with different opening patterns arranged obliquely. This composite arrangement creates angular selectivity that effectively filters ambient light while maintaining structural simplicity. The staggered openings across layers work together to achieve superior light filtering without requiring complex individual 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 design enhances fingerprint recognition accuracy by controlling light reception angles and blocking ambient light, allowing for reduced sensor size and complexity, while maintaining high resolution without increasing production costs.
Implementation Method 1
a plurality of light converged elements, arranged on a side of the plurality of photosensitive devices facing away from the base substrate
Implementation Method 2
each of the plurality of optical channels is configured to allow incident light within an incidence angle of (φ−θ, φ+θ) to be directed onto the photosensitive device
Implementation Method 3
each of the plurality of optical channels is obliquely arranged
Data Source
AI summary
An optical sensor and a display apparatus. The optical sensor includes: a base substrate (1); a detection circuit (2) on the base substrate (1); a plurality of photosensitive devices (3) on a side of the detection circuit (2) facing away from the base substrate (1); a plurality of light converged elements (4) on a side of the photosensitive devices (3) facing away from the base substrate (1); where an orthographic projection of one light converged element (4) on the base substrate (1) covers orthographic projections of at least two photosensitive devices (3) on the base substrate (1); and a light constrained structure (5) between the photosensitive devices (3) and the light converged elements (4).