Light Guide Component with Aperture Array for Fingerprint Optical Crosstalk
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Solution Overview
Problem
In optical fingerprint identification, large distances between the finger and the sensor lead to light scattering, resulting in blurred images and inaccurate fingerprint information due to the scattering of light reflected by the finger.
Innovation Solution
A fingerprint identification device comprising a display panel with a light-emitting surface, a light guide component with a black light-shielding film layer and light-passing holes, and a light sensing component, where the light-passing holes are arranged to filter light reflected from the fingerprint, ensuring that each beam corresponds to the valley or ridge, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the distance between the finger and the sensor is large, then the field of view is increased, but the image becomes blurred due to light scattering
Solution Approach 1:
The patent divides the light collection process into multiple directional channels using a light guide component with multiple light guide units. Each light guide unit collects light from a specific angle range, segmenting the overall field of view into discrete angular zones. This segmentation allows the system to maintain a large field of view while preserving image clarity by preventing light scattering across different spatial locations.
Solution Approach 2:
The patent implements local quality control by assigning different light collection angles to different regions of the light guide component. Each light guide unit has a specific light collection angle designed to match the fingerprint ridge width, ensuring that only light from the correct spatial location and angle reaches the corresponding sensor element. This local optimization maintains measurement precision across the entire large field of view.
2Use of energy by moving object
If the light collection angle is increased to capture more light, then the signal intensity is improved, but the fingerprint ridge and valley cannot be distinguished due to light crosstalk
Solution Approach 1:
The patent employs dynamic angle matching between the light guide component and the fingerprint characteristics. The light collection angle of each light guide unit is specifically designed to correspond to the width of fingerprint ridges. When light reflects off a ridge, it returns at an angle that matches the light guide unit's collection angle, allowing the ridge to be detected. Valley areas, having different geometric properties, reflect light at different angles that do not match the light guide units, preventing false detection and maintaining measurement precision while capturing sufficient signal intensity.
3Device complexity
If a traditional optical sensor is used without light guiding structures, then the device complexity is reduced, but light scattering causes inaccurate fingerprint identification
Solution Approach 1:
The patent introduces a light guide component as an intermediary element between the light source and the sensor. This light guide component actively manages light propagation by collecting reflected light from the fingerprint and directing it to the sensor at appropriate angles. The intermediary structure prevents light scattering from causing measurement errors while maintaining relatively simple device architecture, thus improving reliability without excessive complexity.
Solution Approach 2:
The patent optimizes the light collection angle parameter of the light guide units to match fingerprint ridge width. By carefully selecting and adjusting this critical parameter, the system achieves accurate fingerprint identification. The light collection angle is designed so that light reflected from ridges enters the light guide units efficiently, while light from valleys does not, creating a clear distinction between ridge and valley signals and ensuring reliable fingerprint recognition.
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 solution enhances the accuracy of fingerprint identification by filtering out stray light and ensuring that only relevant light is sensed by the light sensing component, improving recognition accuracy and addressing issues of light crosstalk and low recognition accuracy caused by distance.
Implementation Method 1
the light guide component comprises a light-shielding film layer, the light-shielding film layer is made of a black light-shielding material, the light-shielding film layer is provided with a plurality of light-passing holes along a thickness direction of the light-shielding film layer, and the plurality of light-passing holes are arranged in an array, and each of the light-passing holes has a light collecting angle of θ
Implementation Method 2
a display panel comprising at least one light-emitting surface and an opposite side disposed opposite to the light-emitting surface, the light-emitting surface being configured to approach valley and ridge of a fingerprint to be identified
Implementation Method 3
the valley and ridge of the fingerprint to be identified are configured to receive and reflect light emitted by the display panel
Data Source
AI summary
A fingerprint identification device and a manufacturing method thereof, and a light guide component are provided, the fingerprint identification device includes: a display panel including a light-emitting surface and an opposite side opposite to each other, the light-emitting surface being configured to approach valley and ridge of a fingerprint to be identified; a light guide component disposed on the opposite side; and a light sensing component disposed on a side of the light guide component away from the display panel, the light guide component includes a light-shielding film layer made of a black light-shielding material, the light-shielding film layer is provided with a plurality of light-passing holes arranged in an array, and each of the light-passing holes has a light collecting angle of θ, which is less than or equal to the maximum light collecting angle α at which the valley and ridge of the fingerprint can be distinguished.