Imaging Device Load Transistor Voltage Control for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-resolution imaging devices face challenges in reducing horizontal random noise, which cannot be effectively corrected due to its random nature and the differing vertical signal lines affecting pixels in the same row, leading to significant noise interference.
Innovation Solution
The imaging device incorporates a voltage supply circuit that selectively switches between two voltage levels, using amplification and resistance circuits to reduce 1/f noise by varying the drive frequencies of transistors and stabilizing the voltage supplied to load transistors, thereby minimizing horizontal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant voltage is supplied to the gate of the load transistor, then the circuit operation is simple, but 1/f noise and thermal noise are generated and superimposed on pixel signals
Solution Approach 1:
The voltage supply circuit periodically switches between a first voltage and a second voltage at a frequency higher than the pixel signal frequency. This periodic switching modulates the load transistor operation to move the noise spectrum away from the baseband, reducing 1/f noise and thermal noise superimposition on pixel signals while maintaining relatively simple circuit operation.
2Use of energy by moving object
If the imaging device operates at low frequency, then power consumption is reduced, but 1/f noise increases and superimposes on pixel signals
Solution Approach 1:
The voltage supply circuit implements periodic switching at a frequency higher than the pixel signal frequency, which shifts the noise spectrum to higher frequencies where 1/f noise is reduced. This allows the imaging device to operate with lower overall power consumption while avoiding the dominance of 1/f noise that would occur at lower operating frequencies.
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 horizontal noise by suppressing 1/f noise and thermal noise, improving the quality of pixel signals and reducing noise fluctuations across the imaging device.
Implementation Method 1
a pixel including a photoelectric converter that converts light into charges
Data Source
AI summary
An imaging device provided with: a pixel including a photoelectric converter that converts light into charges, the pixel outputting a first signal corresponding to an amount of the charges; an output signal line coupled to the pixel, the first signal being transmitted through the output signal line; a load transistor having a source, a drain, and a gate, one of the source and the drain being coupled to the output signal line; and a voltage supply circuit coupled to the gate of the load transistor, the voltage supply circuit selectively supplying either a first voltage or a second voltage to the gate.