Image Sensor Pixel Amplifier Capacitance Adjustment
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Solution Overview
Problem
Existing image-capturing devices face fluctuations in conversion gain when summing electric charges from multiple light receiving elements, affecting the accuracy and reliability of image capture.
Innovation Solution
An image sensor design with a first and second photoelectric conversion unit, along with adjustment and connection units, allows for controlled capacitance adjustment and signal combination, stabilizing the conversion gain and ensuring high linearity in signal output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electric charges from multiple light receiving elements are summed together, then the signal strength is improved, but the conversion gain fluctuates
Solution Approach 1:
The patent applies dynamics by making the capacitance value adjustable rather than fixed. The adjustment unit dynamically changes the capacitance at the output unit to compensate for fluctuations in conversion gain, allowing the system to adapt to varying conditions while maintaining stable performance during charge summation operations.
Solution Approach 2:
The patent changes the capacitance parameter at the output unit to stabilize conversion gain. By adjusting this electrical parameter in response to detected gain fluctuations, the system maintains consistent conversion characteristics even when summing charges from multiple photoelectric conversion units.
2Area of moving object
If pixels are miniaturized, then the device density is improved, but the conversion gain stability deteriorates
Solution Approach 1:
The patent implements feedback by detecting conversion gain fluctuations and using this information to adjust the capacitance value. This closed-loop control compensates for the instability introduced by pixel miniaturization, allowing smaller pixels to maintain reliable conversion gain through active compensation.
Solution Approach 2:
The patent makes the output unit dynamically adjustable through the capacitance modification unit, which responds to changing conditions in miniaturized pixels. This dynamic adaptation allows the system to maintain stable conversion gain despite the challenges posed by reduced pixel dimensions.
3Reliability
If capacitance is adjusted at the output unit, then the conversion gain stability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the capacitance adjustment function with the existing output unit structure. The adjustment unit is integrated into the output circuitry, combining multiple functions (charge summation, signal output, and capacitance adjustment) into a unified structure that reduces overall complexity compared to separate independent components.
Solution Approach 2:
The output unit is designed with multi-functionality, serving both as a charge summation node and as a capacitance-adjustable output stage. This universal design allows the same structure to perform multiple functions, reducing the need for additional dedicated components and thereby limiting the increase in device complexity.
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 stabilizes the conversion gain, ensuring high linearity and reliability in image capture by suppressing fluctuations in the charge/voltage conversion process, even as pixels become miniaturized.
Implementation Method 1
a first photoelectric conversion unit that generates an electric charge through photoelectric conversion of light
Data Source
AI summary
An image sensor includes: a first pixel having a first photoelectric conversion unit that generates an electric charge through photoelectric conversion of light, and a first output unit that generates a first signal based upon the electric charge generated by the first photoelectric conversion unit and outputs the first signal; a second pixel having a second photoelectric conversion unit that generates an electric charge through photoelectric conversion of light, and a second output unit that generates a second signal based upon the electric charge generated by the second photoelectric conversion unit and outputs the second signal; and an adjustment unit that adjusts a capacitance at the first output unit upon outputting of the first signal and the second signal from the first output unit.