Vertical Photogate Distance Sensor Light Sensitivity
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Solution Overview
Problem
Conventional distance measuring sensors with double photogates on the light-incident surface suffer from reduced light sensitivity due to the photogates, which diminishes the accuracy of distance measurement.
Innovation Solution
The design incorporates vertically formed photogates in a substrate, creating an enlarged light-receiving region with separate charge storage regions and trenches, allowing for enhanced charge generation and collection, thereby increasing the sensitivity of distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If double photogates are placed on the light-incident surface for distance measurement, then distance measurement function is achieved, but light sensitivity is reduced and measurement precision deteriorates
Solution Approach 1:
The photogates are repositioned from the light-incident surface (2D plane) to the vertical depth dimension of the substrate. This dimensional transition allows the photogates to be placed at different depths (first photogate at first depth, second photogate at second depth) without blocking the incident light path, thereby maintaining light sensitivity while enabling distance measurement through depth-resolved charge collection
Solution Approach 2:
The photogates are nested within the substrate volume rather than being placed on the surface. The first photogate is positioned at a first depth and the second photogate at a second depth within the substrate, creating a nested three-dimensional structure that allows light to pass through the surface unobstructed while still capturing charges at multiple depth levels for distance measurement
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 configuration results in a significant improvement in distance measuring sensitivity, with a current difference of approximately 50% more than conventional sensors, effectively addressing the limitations of existing technologies.
Implementation Method 1
a photoelectric conversion region... doped with a first impurity to generate charges in response to received light
Data Source
AI summary
A distance measuring sensor may include: a photoelectric conversion region; first and second charge storage regions; first and second trenches; and/or first and second vertical photogates. The photoelectric conversion region may be in a substrate and/or may be doped with a first impurity in order to generate charges in response to received light. The first and second charge storage regions may be in the substrate and/or may be doped with a second impurity in order to collect charges. The first and second trenches may be formed to have depths in the substrate that correspond to the first and second charge storage regions, respectively. The first and second vertical photogates may be respectively in the first and second trenches. A three-dimensional color image sensor may include a plurality of unit pixels. Each unit pixel may include a plurality of color pixels and the distance measuring sensor.