Image Sensor Compensation Module for Band Noise Reduction
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Solution Overview
Problem
Image sensors face the challenge of band noise phenomena, where pixels in the same row share a transfer line, leading to voltage drops and noise generation due to varying light intensities, causing dark regions to appear bright.
Innovation Solution
An image sensor design incorporating a compensation module that detects variations in the transfer gate signal and generates a compensation voltage to offset voltage drops, preventing band noise by adjusting signal voltages and using a ramp voltage generation module to output digital codes based on signal comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pixels in the same row share a common transfer line, then device complexity is reduced and manufacturing is simplified, but voltage drops occur due to varying light intensities causing band noise
Solution Approach 1:
The patent divides the common transfer line into multiple independent transfer lines, one for each pixel. This segmentation allows each transfer line to be independently controlled, preventing voltage drops from affecting adjacent pixels and eliminating band noise while maintaining manufacturing simplicity through systematic design
Solution Approach 2:
The patent implements individual transfer lines for each pixel rather than sharing common lines, allowing localized control of voltage levels. Each pixel's transfer line can be optimized independently, ensuring uniform voltage distribution across the sensor array and preventing the propagation of voltage drops that cause band noise
2Object-affected harmful factors
If a compensation module is added to detect voltage variations and generate compensation signals, then band noise is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the compensation function into a dedicated compensation module that is selectively applied only to affected pixels. This modular approach allows the system to maintain simplicity for pixels not requiring compensation while providing targeted noise reduction where needed, balancing complexity and performance
Solution Approach 2:
The compensation module implements a feedback mechanism by detecting voltage variations on transfer lines and generating compensating signals to counteract these variations. This closed-loop approach automatically corrects band noise without requiring complex manual calibration or additional hardware beyond the feedback path
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 solution effectively reduces band noise by stabilizing signal voltages across pixels, improving image sensing accuracy and reducing noise artifacts, thereby enhancing image quality.
Implementation Method 1
a photoelectric element accumulating charges therein by absorbing incident light
Data Source
AI summary
An image sensor is provided. The image sensor includes a pixel array including first and second pixels, the first and second pixels receiving the same transfer gate signal and outputting first and second signal voltages, respectively, a transfer gate driver receiving first and second voltages and generating the transfer gate signal, the transfer gate signal having the first voltage as its maximum voltage and having the second voltage as its minimum voltage and a compensation module detecting a variation in the second voltage, generating a compensation voltage based on the variation in the second voltage, and performing a compensation operation.