Imaging Apparatus Floating Diffusion Transistor Noise Reduction
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Solution Overview
Problem
The existing imaging apparatuses suffer from increased noise components in signal output due to electric charges being trapped and discharged in transistors connected to the floating diffusion region, leading to noise in the pixel signals.
Innovation Solution
A driving method for the imaging apparatus that involves turning the transistor connected to the floating diffusion region off before reading out the signal from the second pixel, thereby reducing the noise components in the signal output by minimizing the discharge of trapped electric charges to the floating diffusion region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transistor connected to the floating diffusion region remains in the on state during signal readout, then the photoelectric conversion unit can transfer electric charges to the floating diffusion region, but electric charges become trapped and discharged in the transistor, increasing noise components in the pixel signal
Solution Approach 1:
The transistor connected to the floating diffusion region is turned off before the photoelectric conversion unit transfers electric charges to the floating diffusion region. This preliminary action prevents electric charges from being trapped in the transistor, thereby eliminating the source of noise that would otherwise be generated when charges are discharged during signal readout.
Solution Approach 2:
The transistor connected to the floating diffusion region is turned on and off periodically according to specific timing sequences. It is turned off during charge transfer to prevent charge trapping, turned on before signal readout to enable signal output, and turned off again after readout to reset the system for the next cycle.
2Object-affected harmful factors
If the transistor connected to the floating diffusion region is turned off before signal readout, then noise components are reduced, but the timing control of the imaging apparatus becomes more complex
Solution Approach 1:
The transistor connected to the floating diffusion region is turned on and off periodically according to specific timing sequences. It is turned off during charge transfer to prevent charge trapping, turned on before signal readout to enable signal output, and turned off again after readout to reset the system for the next cycle.
Solution Approach 2:
The transistor connected to the floating diffusion region is turned off before the photoelectric conversion unit transfers electric charges to the floating diffusion region. This preliminary action prevents electric charges from being trapped in the transistor, thereby eliminating the source of noise that would otherwise be generated when charges are discharged during signal readout.
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 method effectively reduces noise components in the signal output, improving the quality of the pixel signals by controlling the state of the transistor connected to the floating diffusion region during signal readout.
Implementation Method 1
Each of the plurality of pixels includes a photoelectric conversion unit configured to accumulate electric charges generated by photoelectric conversion of light
Data Source
AI summary
In a period in which a pixel signal of another pixel is read out from the pixel, a transistor connected to a floating diffusion region of a pixel not performing reading out of a pixel signal from the pixel is turned off.