Photoelectric Sensor Light Traps for Better Light Localization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current photoelectric sensors have limited photosensitive performance due to insufficient optical sensitivity and light localization capability, primarily because of the small photosensitive area and inefficient light trapping mechanisms.
Innovation Solution
The photoelectric sensor design incorporates a substrate with a light-receiving surface featuring a matrix of pixel unit areas and light traps with an octagonal pyramid structure, where the light traps are connected in a row and column direction, increasing the photosensitive area and optical path difference, and utilizing a wet etching process to form these structures on a cubic crystal substrate with varying etching rates for different crystal planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional planar pixel structures are used, then the device structure is simple, but the photosensitive area is small and optical sensitivity is insufficient
Solution Approach 1:
The patent transforms the traditional two-dimensional planar pixel structure into a three-dimensional structure by forming light traps with protrusions that extend vertically from the substrate surface. Each pixel unit area contains multiple protrusions with inclined surfaces that create additional photosensitive surfaces in the vertical dimension, thereby increasing the total photosensitive area without expanding the horizontal footprint of the device.
Solution Approach 2:
The patent divides each pixel unit area into multiple discrete protrusions rather than using a single planar surface. These protrusions are arranged in a matrix pattern within each pixel unit, with each protrusion providing independent photosensitive surfaces. This segmentation allows light to interact with multiple surfaces within the same horizontal area, effectively increasing the photosensitive area while maintaining a compact device structure.
2Reliability
If simple light trapping structures are used, then the device complexity is low, but the light localization capability is insufficient
Solution Approach 1:
The patent enhances light localization by creating three-dimensional light traps with protrusions that have inclined surfaces extending vertically from the substrate. These vertical structures confine light within the pixel unit area through multiple internal reflections on the inclined surfaces, preventing light from spreading to adjacent pixels. The three-dimensional configuration provides superior light confinement compared to traditional planar light trapping structures.
Solution Approach 2:
The patent combines multiple functional elements into a unified protrusion structure: the protrusion simultaneously serves as a light-trapping element, a photosensitive surface generator, and a light-guiding structure. The inclined surfaces of the protrusions perform multiple functions including reflecting incident light, guiding light to photodetectors, and confining light within the pixel area, thereby achieving enhanced light localization through a single integrated structure rather than multiple separate components.
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
This design significantly enhances the photosensitive performance by increasing the photosensitive area and the number of light reflections, thereby improving the light localization capability and overall optical sensitivity of the sensor.
Implementation Method 1
Among the etching rates of the various crystal planes of the substrate in the wet etching process, the etching rate of the {100} crystal plane is the largest, and the etching rate of the {111} crystal plane is the smallest
Implementation Method 2
A photoelectric sensor is a device that converts optical signals into electrical signals. Its working principle is based on the photoelectric effect. The photoelectric effect means that when light shines on certain substances, electrons of the substances absorb the energy of the photons and a corresponding electrical effect occurs
Data Source
AI summary
A photoelectric sensor includes: a substrate with a light-receiving surface. The substrate includes a photosensitive pixel area and the photosensitive pixel area includes pixel unit areas distributed in a matrix. Light traps are located in a part of a thickness of the substrate in the pixel unit area. The light traps are located on the light-receiving surface of the substrate, and distributed in a matrix along a row direction and a column direction. The row direction is perpendicular to the column direction. Adjacent light traps in the column direction are connected, and adjacent light traps in the row direction are connected. Side walls of the plurality of light traps surround and form a plurality of protrusions. Adjacent protrusions are connected, and the plurality of protrusions has a shape of octagonal pyramid.