Fingerprint Sensor Collimation Structure With Fewer Light-Shielding Layers
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Solution Overview
Problem
Existing fingerprint identification modules face manufacturing difficulties due to the need for multiple stacked light-shielding layers and the thickness requirements of lens-based structures, which complicate the fabrication process and increase production challenges.
Innovation Solution
A fingerprint identification module utilizing a collimating structure formed by a first and second light-shielding layer with through holes and a gap portion, where optical spacers maintain the distance between substrates, reducing the number of film layers and simplifying manufacturing by using an air gap or transparent medium in the gap portion, and improving light collimation and fingerprint identification accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a collimating structure is formed by alternately stacking light-shielding layers and cover layers, then light collimation is achieved, but the number of film layers increases to seven to eight layers making fabrication difficult
Solution Approach 1:
The patent combines multiple light-shielding layers into a single integrated light-shielding layer with multiple through-hole groups, reducing the number of stacked layers from seven to eight down to just three layers (cover layer, light-shielding layer, and sensor layer), thereby simplifying fabrication while maintaining collimation function
Solution Approach 2:
The light-shielding layer is segmented into multiple through-hole groups, where each group corresponds to a row of optical sensors and contains through-holes positioned to collimate light for that specific row, enabling simplified single-layer fabrication while achieving directional light control
2Manufacturing precision
If a lens is used for fingerprint imaging, then imaging function is achieved, but the lens thickness increases making manufacturing difficult for large fingerprint identification areas
Solution Approach 1:
The patent replaces the traditional mechanical lens structure with an optical collimation system using through-holes in a light-shielding layer, eliminating the need for thick lens elements and enabling thin-profile fingerprint sensors suitable for large identification areas
Solution Approach 2:
The invention uses a thin light-shielding layer with precisely positioned through-holes instead of a thick lens, achieving imaging functionality with minimal thickness that can be easily integrated into large-area fingerprint identification modules
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 simplifies the manufacturing process, reduces the number of film layers, and enhances fingerprint identification accuracy by effectively collimating light and limiting the size range of fingerprints collected by each optical sensor, improving signal-to-noise ratio and resolution.
Implementation Method 1
a gap portion between the first light-shielding layer and the second light-shielding layer, the gap portion collimating the light
Data Source
AI summary
A fingerprint identification module collimating light reflected by fingertip skin patterns defines a fingerprint identification area and a peripheral area, for identifying fingerprints. The module includes a first light-shielding layer, optical sensors, a second light-shielding layer, a supporting portion, and a gap portion. The first and second light-shielding layers each define through holes (first and second through holes). Each second through hole exposes one optical sensor and is aligned with one first through hole. The supporting portion in the peripheral area bonds the first and second substrates, maintaining a certain distance between the first and second light-shielding layers. The gap portion is in the fingerprint identification area. Light reflected by a fingerprint is collimated by the first through holes, the gap portion, and the second through holes and then received as optical signals by the sensors to realize fingerprint imaging.