Photodiode Detection Device with Scattering Light Guide for Noise Reduction
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Solution Overview
Problem
Optical sensors face issues with insufficient illumination of light emitted from the front light, leading to reduced contrast for detection, particularly in fingerprint and vein pattern recognition.
Innovation Solution
A detection device comprising a plurality of photodiodes, a light guide plate with scattering portions, an optical filter layer with light-blocking layers, and lenses, which enhances light scattering and directionality to improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a front light is provided with a light guide plate and light source, then illumination is provided to the detection area, but insufficient illumination reduces contrast for detection
Solution Approach 1:
The patent applies local quality by providing different surface characteristics at different locations on the light guide plate. Specifically, the light guide plate has a first surface in contact with the object and a second surface opposite to it, with different optical properties at each surface to optimize both illumination provision and light scattering for enhanced detection contrast
Solution Approach 2:
The patent implements preliminary action by pre-structuring the light guide plate with specific surface configurations before illumination occurs. The light guide plate is designed in advance with particular geometric features and optical properties that will scatter light in desired patterns when illuminated, ensuring optimal detection conditions are already in place before the actual detection process
2Illumination intensity
If light is emitted from the front light, then the detection area is illuminated, but direct light enters the photodiodes causing noise
Solution Approach 1:
The patent uses the light guide plate as an intermediary between the light source and the detection area. The light guide plate receives light from the light source and redistributes it through its structured surfaces, acting as a mediator that transforms direct light into scattered light, thereby preventing direct light from reaching the photodiodes while still providing comprehensive illumination
Solution Approach 2:
The patent converts the potentially harmful direct light into beneficial scattered light. By designing the light guide plate with specific surface structures, the patent transforms direct light that would otherwise cause noise into scattered light that provides uniform illumination and enhances detection contrast, turning a harmful effect into a beneficial one
3Illumination intensity
If scattering portions are added to the light guide plate, then light scattering is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by making the light guide plate perform multiple functions simultaneously. The light guide plate not only guides and distributes light from the light source but also inherently provides scattering functionality through its structured surfaces. This multi-functionality eliminates the need for separate scattering components, reducing overall device complexity while achieving improved light scattering
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 device achieves improved detection accuracy by ensuring that photodiodes are primarily irradiated with light reflected by the object, reducing noise and enhancing sensitivity.
Implementation Method 1
a plurality of scattering portions that are provided on the light guide plate and configured to scatter light from the light source
Implementation Method 2
a plurality of photodiodes arranged on a substrate
Data Source
AI summary
According to an aspect, a detection device includes: a plurality of photodiodes arranged on a substrate; a front light including a light guide plate disposed so as to overlap the photodiodes, a light source configured to emit light to a first side surface of the light guide plate, and a plurality of scattering portions that are provided on the light guide plate and configured to scatter light from the light source; an optical filter layer including at least one light-blocking layer that has a plurality of openings; and a plurality of lenses provided such that each of the photodiodes overlaps more than one of the lenses in plan view.