Protrusion-Based Light Homogenizing Device for Biometric Identification
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Solution Overview
Problem
Conventional light homogenizing devices in fingerprint readers have unsatisfactory light-homogenizing performance, which affects the accuracy of biometric identification.
Innovation Solution
A light homogenizing device with protrusion structures and a circular inclined-plane is used, where light-emitting units emit light to the protrusion structures, which homogenize and transmit the light through a second surface, enhancing light uniformity for improved biometric identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional light homogenizing device (simple sheet) is used, then the device complexity is low, but the light-homogenizing performance is unsatisfying
Solution Approach 1:
The light homogenizing member is segmented into multiple functional regions: a central hole region and multiple protrusion structures surrounding the hole. Each protrusion structure acts as an independent light homogenizing unit, allowing the device to achieve better light homogenization performance through distributed light diffusion while maintaining a relatively simple overall structure.
Solution Approach 2:
The protrusion structures extend in the thickness direction of the light homogenizing member, adding a vertical dimension to light diffusion. This three-dimensional structure enables more effective light scattering and homogenization compared to conventional two-dimensional flat sheets, improving light-homogenizing performance without significantly increasing planar footprint.
2Illumination intensity
If light is directly transmitted through a simple sheet, then the device structure is simple, but the light uniformity is poor
Solution Approach 1:
Different regions of the light homogenizing member have different optical functions: the central hole allows direct light transmission for high intensity, while the surrounding protrusion structures diffuse light for uniformity. This local differentiation of optical properties enables the device to simultaneously achieve both high light intensity and good uniformity across the illumination area.
Solution Approach 2:
The protrusion structures serve as intermediary elements between the light source and the finger. These structures receive light from the light-emitting units and redistribute it through diffusion and refraction, acting as a mediating layer that transforms non-uniform light into uniform illumination while maintaining structural simplicity.
3Manufacturing precision
If protrusion structures are added to homogenize light, then light-homogenizing performance improves, but manufacturing complexity increases
Solution Approach 1:
The protrusion structures can be manufactured by controlling the thickness parameter of the light homogenizing member during fabrication. By varying the thickness in specific regions to create protrusions, the device achieves complex optical functionality through a single parameter change (thickness variation) rather than requiring multiple assembly steps or complex加工工艺.
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 enhanced light homogenization improves the quality of images captured, leading to increased accuracy in biometric identification, such as fingerprint recognition.
Implementation Method 1
The protrusion structures homogenizes the light and outwardly transmits the homogenized light through a second surface of the light homogenizing member
Implementation Method 2
A circular inclined-plane is disposed between the hole and the protrusion structures, and the circular inclined-plane is connected to the hole
Data Source
AI summary
The present disclosure provides a light homogenizing device and a biometric identifying device. The light homogenizing device includes a light homogenizing member and light-emitting units. The light homogenizing member includes a hole and protrusion structures. The protrusion structures are disposed on a first surface of the light homogenizing member and surrounding an outside of the hole. A circular inclined-plane is disposed between the hole and the protrusion structures and connected to the hole. The light-emitting units are disposed opposite to the first surface, and each light-emitting units transmits a light to one of the protrusion structures. The protrusion structures homogenize the light and outwardly transmit the homogenized light through a second surface of the light homogenizing member.