Image Pickup Apparatus Transfer Switch Control for Signal Correction
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Solution Overview
Problem
Existing image pickup apparatuses with global electronic shutters face challenges in achieving high accuracy for signal correction due to insufficient accuracy in correcting pseudo signals, leading to image quality degradation.
Innovation Solution
The image pickup apparatus includes a plurality of pixels with a photoelectric conversion unit, a holding unit, and transfer switches that control the transfer of charges to achieve a global electronic shutter operation, allowing for sequential reading of real and pseudo signal charges, with the second reading period optimized to improve accuracy and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the second transfer switch is turned on once to read out pseudo signal charges, then the correction signal can be obtained, but the accuracy of the correction signal is insufficient
Solution Approach 1:
The second transfer switch is turned on multiple times at different time points (third time, fourth time, and fifth time) to periodically read out pseudo signal charges. This periodic action allows accumulation of multiple correction signals, improving the accuracy of the correction through averaging or integration, while maintaining the same basic switch control mechanism without adding complex hardware.
2Measurement precision
If multiple transfer operations are performed to improve signal accuracy, then correction precision increases, but power consumption increases
Solution Approach 1:
The photoelectric conversion unit accumulates charges during the accumulation period before any transfer operations. By preparing the charges in advance and using the first transfer switch to move them to the holding unit, the system minimizes the number of times charges need to be transferred. The second transfer switch is then used only for reading pseudo signal charges multiple times without requiring additional charge accumulation cycles, thereby reducing overall power consumption while maintaining correction accuracy.
3Reliability
If the first transfer switch remains on during the period from third time to fourth time, then charge transfer is continuous, but pseudo signal contamination increases
Solution Approach 1:
The first transfer switch is dynamically controlled to be turned off during the period from the third time to the fourth time when the second transfer switch is reading pseudo signal charges. This dynamic control prevents false charges generated during the reading process from contaminating the signal. The switch timing is optimized to be off only when necessary, balancing signal purity with transfer efficiency.
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 enhances the accuracy of signal correction, alleviates image quality degradation caused by pseudo signals, and allows for higher frame rates and reduced power consumption while simplifying the image pickup system configuration.
Implementation Method 1
a photoelectric conversion unit configured to perform accumulation of charges generated by incident light
Data Source
AI summary
A photoelectric conversion unit in each of a plurality of pixels starts accumulation of charges at a first time and is controlled to be turned on after the first time and to be thereafter turned off at a second time to transfer the charges to a holding unit. A second transfer switch in at least one of the pixels is controlled to be turned on at a third time and a fourth time after the second time to transfer the charges held in the holding unit to an amplification unit, and a first transfer switch in the at least one of the pixels is maintained to be in an off state during a period from the third time to a fourth time.