Thin Collimator Structure for Accurate Texture Image Acquisition
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Solution Overview
Problem
Existing optical texture recognition systems face challenges with thick collimator structures, high fabrication costs, and low yield, leading to inaccurate fingerprint recognition due to scattered light rays, especially when the distance between the finger and image sensor is large.
Innovation Solution
A collimator structure comprising a lens array, first and second diaphragm layers, and optional third diaphragm layer, stacked on an image sensor, which converges and collimates light rays while restricting angles to improve image accuracy and prevent light crosstalk, with a thickness less than 100 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional collimator structure is used, then light rays can be converged, but the collimator thickness is large and fabrication cost is high
Solution Approach 1:
The collimator is segmented into multiple functional layers: a lens array layer for light convergence, a first diaphragm layer with through holes for angle restriction, and a second diaphragm layer adjacent to the image sensor. This segmentation allows each layer to perform its specific function with minimal thickness, achieving effective collimation without requiring a thick single-component structure.
Solution Approach 2:
The invention transitions from a conventional single-layer thick collimator to a multi-layer stacked structure where functions are distributed across different dimensions (layers). The lens array, first diaphragm layer, and second diaphragm layer are stacked sequentially, with each layer contributing to the overall collimation function while maintaining a thin total profile.
2Measurement precision
If a conventional collimator structure is used, then light rays can be converged, but fabrication cost is high and yield is low
Solution Approach 1:
The collimator is divided into separate manufacturable layers (lens array, first diaphragm layer, second diaphragm layer) that can be fabricated independently using standard semiconductor or microfabrication processes, then stacked together. This segmentation enables mass production with higher yield and lower cost compared to manufacturing a single integrated thick collimator.
Solution Approach 2:
The stacked structure serves multiple functions simultaneously: the lens array converges light, the first diaphragm layer restricts light angles, and the second diaphragm layer further refines angle restriction. This multi-functionality is achieved through a thin, integrated stacked structure that can be manufactured using universal microfabrication techniques applicable to various imaging devices.
3Adaptability or versatility
If the distance between finger and image sensor is large, then authentication can be performed, but light rays scatter and recognition accuracy decreases
Solution Approach 1:
The first diaphragm layer introduces local quality control by restricting light angles at a specific location within the optical path. This angle restriction ensures that only light rays within a specific angular range reach the image sensor, maintaining image quality and recognition accuracy even when the finger-to-sensor distance varies, thereby providing adaptability without sacrificing precision.
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 proposed collimator structure enhances texture image acquisition accuracy by reducing light scattering and crosstalk, offering a thin and cost-effective solution suitable for various applications.
Implementation Method 1
The lens array is configured to allow light rays to be converged and incident on the first diaphragm layer
Implementation Method 2
The first diaphragm layer is configured to allow light rays incident on the first diaphragm layer to pass through and be incident on the second diaphragm layer, and to restrict an angle of light rays capable of passing through the first diaphragm layer
Implementation Method 3
The image sensor is configured to sense light rays incident on the image sensor for acquiring a texture image
Data Source
AI summary
A texture image acquiring device, a display device and a collimator are disclosed. The texture image acquiring device includes a collimator and an image sensor. The collimator includes a lens array and diaphragm component. The diaphragm component includes a first diaphragm layer and a second diaphragm layer. The lens array is configured to allow light rays to be converged and incident on the diaphragm component. The diaphragm component is configured to allow light rays to pass through, and to restrict an angle of light rays capable of passing through the diaphragm component. The image sensor is configured to sense light rays incident on the image sensor for acquiring a texture image.