Image Sensor PD Bias Patterns for Color Separation and Leakage Control
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Solution Overview
Problem
Current image sensors face challenges in efficiently receiving light in different colors using a single photodiode and preventing photoelectron leakage, which affects their performance and efficiency.
Innovation Solution
The design includes conductive bias patterns and pixel isolation patterns around a photodiode region, allowing for the generation of photoelectrons with different color information and blocking leakage paths, enabling efficient light reception and improved photoelectron generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the physical volume of the photodiode is reduced to increase resolution, then the resolution is improved, but the capability for generating photoelectrons deteriorates
Solution Approach 1:
The photodiode region is divided into multiple quadrants (first to fourth quadrants) with separate bias patterns applied to each quadrant. This segmentation allows independent control of different regions, enabling the photodiode to receive light in multiple colors simultaneously while maintaining adequate photoelectron generation capability in each segmented region.
Solution Approach 2:
Different bias patterns are applied to different quadrants of the photodiode region, creating local quality variations. Each quadrant can be optimized for specific color reception, allowing the overall photodiode to handle multiple colors effectively while each local region maintains sufficient photoelectron generation capability.
2Device complexity
If a single photodiode is used to receive light in four colors, then the device complexity is reduced, but the reliability of photoelectron generation deteriorates due to leakage
Solution Approach 1:
The single photodiode is segmented into multiple quadrants with independent bias control, allowing simultaneous reception of different colors. This segmentation prevents photoelectron leakage between color channels while maintaining the simplicity of using a single photodiode structure.
Solution Approach 2:
Bias patterns are introduced as intermediary elements between the light input and photoelectron generation process. These bias patterns control the electrical characteristics of different quadrants, enabling reliable photoelectron generation for multiple colors by preventing leakage and optimizing each quadrant's response.
3Measurement precision
If photodiode size is reduced to increase resolution, then the resolution is improved, but the photoelectron generation capability deteriorates
Solution Approach 1:
The reduced-size photodiode is divided into multiple quadrants, each optimized for specific color reception. This segmentation allows the small photodiode to maintain adequate photoelectron generation capability in each quadrant while collectively handling multiple colors, thus preserving resolution benefits.
Solution Approach 2:
Different bias patterns are applied to different quadrants to optimize local photoelectron generation for specific colors. This local optimization ensures that even in a reduced-size photodiode, each region contributes effectively to photoelectron generation for its designated color range.
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 enhances the image sensor's capability to receive light in various colors using a single photodiode, maintaining the efficiency of photoelectron generation without leakage, thereby improving overall performance.
Implementation Method 1
a photosensing region in a substrate and configured to generate photoelectrons in response to an incident light on the photodiode region
Data Source
AI summary
An image sensor may include a photosensing region in a substrate and configured to generate photoelectrons in response to an incident light on the photodiode region, conductive bias patterns disposed to be spaced apart from one another and surrounding the photosensing region, and pixel isolation patterns that are spaced apart from and disposed in a periphery of the conductive bias patterns.