Fingerprint Reader Press Sheet Light Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The assembly of total reflection type fingerprint readers is complicated due to the precise arrangement of optical modules and imaging apparatus, leading to uneven light distribution and blurred images.
Innovation Solution
A press sheet comprising a transparent substrate with a microstructure layer and a diffusion layer, where the diffusion layer includes resin and particles with a refractive index difference, enhancing light distribution and integrated with a protective layer for improved imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a point light source is used in optical fingerprint reader, then the device structure is simple, but the light distribution is uneven leading to blurred images
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the point light source and the fingerprint sensor. This light guide plate diffuses the light from the point source to create uniform illumination across the sensing area, resolving the contradiction by adding a mediating element that transforms the light distribution without significantly increasing device complexity
Solution Approach 2:
The patent modifies the physical parameters of the light guide plate, specifically its thickness and refractive index, to optimize light diffusion. By changing these parameters, the system achieves uniform light distribution while maintaining a simple overall device structure, thus resolving the contradiction between structural simplicity and illumination quality
2Manufacturing precision
If optical module and optical imaging apparatus are precisely arranged, then imaging quality is improved, but assembly complexity increases
Solution Approach 1:
The patent merges the light guide plate with the fingerprint sensor housing or substrate, integrating multiple functions into a single component. This integration reduces assembly complexity by eliminating separate alignment steps while maintaining imaging quality through the unified design
Solution Approach 2:
The light guide plate serves multiple functions: it diffuses light, provides structural support, and acts as a mounting substrate for the fingerprint sensor. This multi-functionality reduces the number of components and simplifies assembly while ensuring proper imaging through its optical design
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 results in uniform light distribution and high haze values, enhancing fingerprint imaging accuracy and clarity, with the diffusion layer's thickness and particle ratio optimizing image quality.
Implementation Method 1
The diffusion layer is disposed on the second surface of the transparent substrate, and comprises a plurality of diffusion particles. The resin and the diffusion particles have a refractive index difference of 0.01 to 1.5.
Implementation Method 2
The microstructure layer is disposed on the first surface of the transparent substrate. It is difficult and complicated to assemble the total reflection type fingerprint reader. Since people must precisely arrange the optical module and an optical imaging apparatus in the assembly process in order to effectively adjust the angle of the light incident and emergent beams.
Data Source
AI summary
A press sheet for fingerprint reader and a fingerprint reader are provided. The press sheet includes a transparent substrate, a microstructure layer, and a diffusion layer. The transparent substrate has a first surface and a second surface, and the first surface faces towards an optical imaging apparatus. The microstructure layer is disposed on the first surface of the transparent substrate, and the diffusion layer contains diffusion particles.