Avalanche Photodiode Pixel Layout for Photon Leakage Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Avalanche light emission from effective pixels can induce avalanche multiplication in adjacent optical black pixels, degrading image quality in photoelectric conversion apparatuses with adjacent effective and optical black pixels.
Innovation Solution
The photoelectric conversion apparatus is designed with a pixel area comprising effective, dummy, and optical black pixels, where the dummy pixels are arranged between effective and optical black pixels to separate them, reducing light intrusion and photon leakage, and the dummy pixels are periodically recharged to prevent potential changes in their terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If effective pixels and optical black pixels are disposed adjacent to each other, then the device complexity is reduced and manufacturing is simplified, but avalanche light emission from effective pixels induces avalanche multiplication in optical black pixels, degrading image quality
Solution Approach 1:
The patent introduces a dummy pixel as an intermediary element disposed between the effective pixel and the optical black pixel. This dummy pixel acts as a buffer that prevents direct interaction between the two functional pixels, thereby blocking the propagation of avalanche light emission from effective pixels to optical black pixels while maintaining the overall simplicity of the pixel array structure
Solution Approach 2:
The patent segments the pixel array into distinct functional zones by inserting dummy pixels between effective pixels and optical black pixels. This segmentation creates separate regions with different functions, preventing the harmful coupling effect while allowing each pixel type to operate independently according to its intended function
2Reliability
If dummy pixels are disposed between effective pixels and optical black pixels, then photon leakage and avalanche light emission are reduced, but the pixel area increases and manufacturing complexity increases
Solution Approach 1:
The dummy pixels perform multiple functions simultaneously: they act as optical barriers to block avalanche light emission, serve as charge collection regions, and maintain the structural integrity of the pixel array. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in manufacturing complexity despite the added pixel elements
3Reliability
If dummy pixels are disposed between effective pixels and optical black pixels, then the pixel area increases, but photon leakage is reduced
Solution Approach 1:
The patent optimizes the parameters of dummy pixels including their dimensions, positioning, and electrical characteristics to achieve maximum photon leakage prevention with minimal area occupation. By carefully adjusting these parameters, the patent reduces the overhead area penalty while maintaining the protective function against avalanche light emission
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 effectively reduces avalanche light emission and photon leakage, stabilizing the pixel array and maintaining image quality by separating and stabilizing the pixel areas, thereby preventing image degradation.
Implementation Method 1
effective pixels that output a photon detection signal responsive to photo detection
Implementation Method 2
avalanche photodiode including an anode and a cathode
Data Source
AI summary
A photoelectric conversion apparatus includes a pixel area including a plurality of pixels each including an avalanche photodiode including an anode and a cathode. The plurality of pixels includes effective pixels that output a photon detection signal responsive to photo detection, dummy pixels that do not output the photon detection signal, and optical black pixels including a light shielding portion. The pixel area includes a first area including the effective pixels, a second area including the dummy pixels, and a third area including the optical black pixels. The second area includes a first portion in contact with an end of the pixel area and a second portion. The first portion, the first area, the second portion, and the third area are disposed in this order in a first direction. A width of the second portion is larger than a width of the first portion in the first direction.