Under-screen optical sensor pinhole array for fingerprint sensing
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Solution Overview
Problem
Conventional fingerprint authentication methods, such as passwords and capacitive sensors, face limitations in security and user convenience, particularly in portable devices where space is limited and background light interference affects optical fingerprint sensing accuracy.
Innovation Solution
An under-screen optical sensor module incorporating a pinhole layer and lens layer for spatial filtering, combined with extra illumination light sources to enhance optical fingerprint sensing, allowing for 2D and 3D topographical fingerprint capture and live finger detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitive sensors are used for fingerprint authentication, then space requirements are reduced, but security and user convenience are compromised
Solution Approach 1:
The optical sensor module is segmented into distinct functional layers: a light source layer, a pinhole array layer for spatial filtering, and an optical sensor array layer. This segmentation allows each layer to perform its specific function optimally while maintaining overall system compactness suitable for portable devices.
Solution Approach 2:
The patent transitions from conventional 2D capacitive sensing to 3D optical sensing by introducing vertical layering with the pinhole array positioned above the optical sensor array. This dimensional change enables depth perception and topographical fingerprint capture, enhancing security while managing space through vertical integration.
2Measurement precision
If optical sensors are used for fingerprint sensing, then authentication accuracy is improved, but background light interference affects sensing precision
Solution Approach 1:
The pinhole array layer extracts and isolates light signals originating from the fingerprint region by allowing only light passing through specific pinhole positions to reach the optical sensor array. This extraction mechanism effectively removes background light interference while preserving fingerprint pattern information.
Solution Approach 2:
The pinhole array serves as an intermediary optical element between the light source and the optical sensor array. It mediates the light transmission by spatially filtering the light, allowing only the relevant fingerprint pattern light to pass through while blocking harmful background light, thereby improving measurement precision.
3Area of stationary object
If an under-screen optical sensor module is implemented, then space requirements are minimized, but optical path length is reduced affecting light detection
Solution Approach 1:
The patent utilizes the vertical dimension by stacking the light source, pinhole array, and optical sensor array in multiple layers. This vertical integration minimizes the horizontal footprint while compensating for the reduced optical path length through optimized vertical spacing and positioning, enabling compact under-screen implementation without sacrificing detection capability.
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 provides robust, secure, and user-friendly fingerprint authentication by minimizing space requirements and reducing background light interference, while capturing detailed fingerprint patterns and distinguishing between real and fake fingers.
Implementation Method 1
a pinhole layer structured to include an array of pinholes and located above the optical sensor array to spatially filter incident light to be detected by the optical detectors
Implementation Method 2
a lens layer structured to include an array of lenses formed above the pinhole layer where the lenses are spatially separated and positioned so that one lens is placed above one corresponding pinhole
Implementation Method 3
an optical sensor array of optical detectors to detect light that carries a fingerprint pattern
Data Source
AI summary
Devices are provided for providing on-screen optical sensing of fingerprints by using an under-screen optical sensor module for improved optical fingerprint sensing including using an optical sensor module to include (1) an optical sensor array of optical detectors to detect light that carries a fingerprint pattern, (2) a pinhole layer structured to include an array of pinholes and located above the optical sensor array to spatially filter incident light to be detected by the optical detectors; and (3) a lens layer structured to include an array of lenses formed above the pinhole layer where the lenses are spatially separated and positioned so that one lens is placed above one corresponding pinhole in the array of pinholes and different lenses in the lens array are placed above different pinholes in the array of pinholes, respectively, to allow the optical sensor array to receive and detector the incident light.