Pixel Driving Voltage Adjustment for Solid-State Imaging Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid-state imaging devices face challenges in setting a suitable transfer driving voltage level for charge transfer, leading to noise generation and image quality disturbances due to varying environmental conditions and device-specific factors.
Innovation Solution
The solution involves setting an intermediate voltage level that does not disturb the complete transfer charge amount, specifying the actual saturated and intermediate voltage retained charge amounts, and adjusting the intermediate voltage to match the expected value, ensuring no information deletion and thus no noise generation, by using a feedback loop to adjust the transfer driving voltage level based on device-specific and environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an intermediate voltage level is used for charge transfer, then the dynamic range is extended and saturation is avoided, but noise is generated due to information deletion
Solution Approach 1:
The patent implements a feedback mechanism where the intermediate voltage level is adjusted based on the actual intermediate voltage retained charge amount to match the expected value. This feedback loop prevents information deletion and noise generation while maintaining the extended dynamic range benefits of intermediate voltage transfer.
Solution Approach 2:
The patent dynamically adjusts the intermediate voltage level parameter based on device-specific and environmental conditions. By changing this parameter to match the expected retained charge amount, the system avoids noise while preserving the wide dynamic range capability.
2Device complexity
If the transfer driving voltage level is fixed, then the device complexity is reduced, but the image quality deteriorates under varying environmental conditions
Solution Approach 1:
The patent performs preliminary characterization to determine the expected intermediate voltage retained charge amount for each device before actual operation. This preliminary action stores device-specific parameters that enable adaptive voltage control without adding complexity to the operational circuitry.
Solution Approach 2:
The system uses its own output (retained charge amount) to automatically adjust the intermediate voltage level. This self-service mechanism eliminates the need for external complex control systems while maintaining image quality under varying environmental conditions.
3Measurement precision
If the intermediate voltage level is adjusted for each device, then the measurement precision is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent performs preliminary measurement and characterization of each device's intermediate voltage retained charge amount during or after manufacturing. This one-time preliminary action captures device-specific parameters that enable precise voltage control without requiring complex adjustment mechanisms during normal operation or additional manufacturing steps.
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 approach allows for reliable and appropriate setting of transfer driving voltage levels, ensuring high S/N ratio and wide dynamic range images without saturation, even in varying light conditions, by accurately managing the intermediate voltage retained charge amount.
Implementation Method 1
a charge generator (a so-called sensor unit, such as a photodiode or the like), which is sensitive to electromagnetic waves from the outside, such as light
Data Source
AI summary
A solid-state imaging device includes: a pixel array unit having arranged unit pixels, each having a charge generator generating signal charges, and a signal output unit having a charge transfer unit, and generating and outputting a processing-target signal corresponding to the signal charges; a driving controller driving the unit pixels, the driving controller sequentially driving the charge transfer unit; and a transfer driving voltage setting unit setting, on the basis of a pixel signal based on a saturated charge amount of the charge generator and a pixel signal based on an intermediate voltage retained charge amount retained in the charge generator after intermediate transfer in which charge transfer is performed at a level between a complete transfer level and an off level, the level of the intermediate voltage such that an actual intermediate voltage retained charge amount becomes the expectation value of the intermediate voltage retained charge amount.