Solid-State Imaging Device Power Supply Noise Correction
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Solution Overview
Problem
Conventional CMOS solid-state imaging devices suffer from image quality deterioration due to noise superimposed on the power supply voltage, which is not effectively addressed by existing noise reduction methods, leading to noise in traverse lines and image quality degradation.
Innovation Solution
A solid-state imaging device equipped with a power supply variation detector and corrector that detects noise components in the power supply voltage and corrects pixel signals using averaging, attenuation, and subtraction circuits to reduce noise-induced image quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a capacitor element is connected between a signal line in a comparator and a power supply line to reduce circuit noise, then potential variations in the power supply line are reduced, but disturbance noise such as power supply noise cannot be effectively eliminated
Solution Approach 1:
The patent extracts the power supply noise component from the pixel signal by using a detection circuit that specifically measures the noise superimposed on the power supply voltage. This separated noise component is then processed independently through averaging and subtraction operations, effectively removing it from the final image signal without affecting the original pixel data.
Solution Approach 2:
The patent implements a feedback mechanism where the power supply noise detected by the detection circuit is fed back to the noise correction circuit. This feedback loop enables real-time compensation by continuously monitoring the power supply voltage variations and adjusting the noise correction accordingly, ensuring that the noise removal adapts to changing power supply conditions.
2Object-affected harmful factors
If noise correction circuits are added to reduce power supply noise, then image quality deterioration is reduced, but device complexity increases
Solution Approach 1:
The patent segments the noise correction function into distinct modular components: a detection circuit for measuring power supply noise, an averaging circuit for processing the noise data, and a subtraction circuit for removing the noise from pixel signals. This segmentation allows each component to perform its specific function efficiently while maintaining overall system manageability and reducing design complexity.
Data Source
AI summary
A solid-state imaging device includes: a pixel array unit in which a plurality of pixels are arranged in rows and columns; a plurality of column signal lines which are provided in one-to-one correspondence with pixel columns; a column processor including a plurality of column AD circuits provided in one-to-one correspondence with the plurality of column signal lines; a power supply variation detector which is connected to a power supply wire through which a power supply voltage is transmitted to each of the pixels, and which detects, in correspondence with pixel rows, power supply variation components attributed to variations in the power supply voltage; and a power supply variation corrector which corrects, for each of the pixel rows, a pixel signal detected by the column processor, using the power supply variation components detected by the power supply variation detector.