Dual Array Sensor Charge Transfer Noise Control
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Solution Overview
Problem
Existing sensors face noise issues due to dark current noise accumulation in charge storage units, which degrades image quality over time, especially as the stored charge is transferred externally, and existing methods cannot effectively discharge unnecessary charges after noise is added to the image.
Innovation Solution
A sensor system with dual photoelectric conversion units and storage units, where charges are transferred and controlled using multiple transport gates and a control unit to minimize storage time and equalize charge distribution, allowing for high and low resolution image reading modes, and an unnecessary charge discharge unit to prevent noise output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If charge is stored in the charge storage unit for a long time, then the image signal can be transferred externally, but dark current noise accumulates and degrades image quality
Solution Approach 1:
The sensor is divided into two separate photoelectric conversion element arrays (first and second arrays) with separate charge storage capabilities. This segmentation allows independent control of charge storage and transfer operations, enabling the system to discharge unnecessary charges from one array while the other array continues to accumulate signal charges, thereby reducing overall noise accumulation in the system
Solution Approach 2:
The control unit periodically switches between the first and second photoelectric conversion element arrays, transferring charges from the first array to the second array at regular intervals. This periodic action prevents excessive charge accumulation time in any single array, thereby minimizing dark current noise while ensuring continuous image signal availability for external transfer
2Object-generated harmful factors
If existing discharge methods are used, then unnecessary charge can be discharged after external transfer, but noise already added to the image cannot be removed
Solution Approach 1:
The system performs preliminary charge discharge operations by transferring charges from the first photoelectric conversion element array to the second array before external transfer occurs. This preliminary action removes unnecessary charges and reduces noise accumulation proactively, rather than attempting to remove noise after it has been added to the image signal
Solution Approach 2:
The second photoelectric conversion element array serves as an intermediary storage unit that receives charges from the first array before external transfer. This intermediary structure allows the system to separate the charge storage function from the noise accumulation problem, enabling effective charge management and noise reduction while maintaining image signal integrity
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 suppresses image unevenness and quality degradation by controlling charge transfer times and discharging unnecessary charges, ensuring high-quality image acquisition by minimizing noise impact.
Implementation Method 1
pixels that generate signal charges by photoelectric conversion
Data Source
AI summary
A sensor includes a photoelectric conversion unit including a first photoelectric conversion element array and a second photoelectric conversion element array, each having an array of a plurality of photoelectric conversion elements arranged in a predetermined direction, a storage unit configured to store a charge generated by the photoelectric conversion unit, a transfer unit configured to transfer the charge generated by the photoelectric conversion unit to an outside of the sensor, a control unit configured to serially execute a first transfer control for transporting unit configured to transport a charge stored in the second photoelectric conversion element array to the transfer unit via the storage unit and a second transfer control for transporting unit configured to transport a charge stored in the first photoelectric conversion element array to the transfer unit via the second photoelectric conversion element array and the storage unit.