Pixel Capacitance Switching for Adaptive Imaging Sensitivity
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Solution Overview
Problem
Current imaging devices lack the ability to dynamically adjust sensitivity, which limits their adaptability to varying lighting conditions and results in suboptimal performance in terms of dynamic range and signal-to-noise ratio.
Innovation Solution
The imaging device incorporates a sensitivity switching circuit with a capacitance element and a transistor that can be controlled based on photography modes, allowing the sensitivity to be adjusted by connecting the capacitance element directly to the photoelectric converting portion and applying a direct-current potential, thereby enhancing sensitivity control and noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sensitivity switching circuit is added to dynamically adjust sensitivity, then adaptability to varying lighting conditions is improved, but device complexity increases
Solution Approach 1:
The patent changes the electrical parameters of the pixel circuit by introducing a sensitivity switching circuit that adjusts the capacitance value connected to the photoelectric converting portion. By switching between different capacitance values (first capacitance value and second capacitance value), the sensitivity of the imaging device is dynamically adjusted to match varying lighting conditions, thus improving adaptability without requiring multiple separate circuits for different modes.
Solution Approach 2:
The patent implements dynamic sensitivity adjustment by making the capacitance connection configurable through a switching mechanism. The sensitivity switching circuit can dynamically change the capacitance value during operation based on lighting conditions, transforming a static pixel circuit into a dynamic one that adapts to environmental changes, thereby improving versatility while maintaining manageable complexity through controlled dynamism.
2Measurement precision
If capacitance element is connected directly to photoelectric converting portion, then sensitivity control is improved, but leakage current increases
Solution Approach 1:
The patent controls leakage current by changing the capacitance parameter dynamically. By switching between a first capacitance value (when sensitivity switching transistor is off) and a second capacitance value (when transistor is on), the system optimizes the balance between sensitivity control and leakage current suppression. The parameter change allows the circuit to achieve precise sensitivity control while minimizing harmful leakage effects through appropriate capacitance selection.
3Measurement precision
If sensitivity is increased to capture more signal, then signal-to-noise ratio is improved, but dynamic range is reduced
Solution Approach 1:
The patent resolves the trade-off between signal-to-noise ratio and dynamic range by implementing dynamic sensitivity adjustment. The sensitivity switching circuit can switch between different capacitance values depending on lighting conditions: using a first capacitance value for high dynamic range requirements and a second capacitance value for improved signal-to-noise ratio. This dynamic adaptability allows the system to optimize both parameters across different operating conditions, achieving versatility that covers both high SNR and wide dynamic range scenarios.
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 solution enables the imaging device to achieve a wide dynamic range and improved signal-to-noise ratio by allowing sensitivity to be adjusted according to lighting conditions, reducing leakage current and noise, and maintaining high image quality without increasing pixel size.
Implementation Method 1
a photoelectric converting portion that converts incident light into signal charge
Data Source
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AI summary
An imaging device 101 comprises a first pixel 11. The first pixel 11 has a photoelectric converting portion 15, a first capacitance element 71, and a first transistor 72. The photoelectric converting portion 15 converts incident light into signal charge. The first capacitance element 71 includes a first terminal 71a and a second terminal 71b, the first terminal 71a being electrically connected to the photoelectric converting portion 15 in at least a period of exposure. The first transistor 72 includes a first source and a first drain, one of the first source and the first drain is electrically connected to the second terminal 71b, and a direct-current potential is applied to the other of the first source and the first drain.