CMOS Imaging Element Read Row Timing Control
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Solution Overview
Problem
When performing two or more read scans of pixel signals in parallel, significant voltage fluctuations in the pixel power source occur, leading to noise in the image due to the movement of read rows, which affects image quality.
Innovation Solution
An imaging element with a vertical drive circuit that controls the movement of read rows based on the position of another read scan, utilizing areas like dummy areas and OPB areas to adjust the read load and timing, ensuring equal or greater movement to minimize voltage fluctuations, and performing long-time and short-time exposures in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two or more read scans of pixel signals are performed in parallel, then productivity is improved, but voltage fluctuations occur leading to noise in the image
Solution Approach 1:
The vertical drive circuit performs preliminary control actions by predicting the position of read rows in parallel read scans and preemptively adjusting their timing to prevent voltage fluctuations before they occur. This anticipatory control prevents the harmful effect of noise generation during parallel read operations.
Solution Approach 2:
The vertical drive circuit implements feedback control by continuously monitoring the position of read rows in parallel read scans and adjusting the timing of read row movement based on the actual positions. This closed-loop control ensures that read rows are moved by equal to or more than a predetermined amount, preventing voltage fluctuations and noise generation.
2Object-affected harmful factors
If read row timing is controlled to prevent voltage fluctuations, then image quality is improved, but device complexity increases
Solution Approach 1:
The vertical drive circuit controls the timing parameter of read row movement to be equal to or more than a predetermined amount, based on the positions of read rows in other read scans. By adjusting this timing parameter dynamically, the circuit prevents voltage fluctuations without requiring complex additional hardware structures.
Data Source
AI summary
The present technique relates to an imaging element, a driving method of the imaging element, and an electronic device that can improve image quality of an image in a case where two or more read scans of pixel signals are performed in parallel. The imaging element includes a pixel area including a plurality of pixels arranged in a matrix, a vertical drive circuit that drives the pixels in the pixel area row-by-row, and a column signal processing circuit that can read pixel signals of a plurality of rows in the pixel area in one horizontal period. The vertical drive circuit performs two or more read scans of the pixel signals in the pixel area in parallel and controls a timing of moving a read row of each read scan by equal to or more than a predetermined amount of movement on the basis of a position of a read row of another read scan. The present technique can be applied to, for example, a CMOS image sensor.