Photoelectric Conversion Element Separate Control Line Wiring
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Solution Overview
Problem
Conventional imaging devices face challenges in maintaining image quality when increasing the number of imaging elements, as they struggle to output effective and dark signals simultaneously, leading to image quality deterioration due to stripe noise and black level emphasis, especially when optical black pixels are not arranged effectively.
Innovation Solution
A photoelectric conversion element with a configuration that includes separate wiring for control lines associated with each pixel, allowing for selective readout operations and signal handling, enabling the suppression of stripe noise without the need for optical black pixels in the effective imaging region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If three or more imaging elements are aligned in the vertical or horizontal direction, then the imaging region area is increased, but the optical black pixels are arranged in the boundary portion causing image quality deterioration
Solution Approach 1:
The imaging elements are segmented into different readout operation types (first and second readout operations), allowing boundary pixels to be handled differently from effective pixels. This segmentation enables the system to process boundary portions with specialized readout sequences that prevent image quality deterioration while maintaining large imaging area coverage.
Solution Approach 2:
The control lines act as intermediaries that selectively control the readout operations of different pixels. By using separate control lines for different pixel types (effective pixels vs. boundary pixels), the system can mediate between the need for large imaging area and the need for high image quality at boundaries, preventing stripe noise and black level emphasis.
2Area of stationary object
If optical black pixels are not arranged, then the effective imaging region is maximized, but it is not possible to obtain reference signal for subtracting black noise
Solution Approach 1:
The first pixels, which are part of the effective imaging region, are given multi-functionality by enabling them to perform both optical signal readout and reset signal readout. This allows certain effective pixels to serve dual purposes: capturing image data and providing reference signals for black noise subtraction, thereby eliminating the need for dedicated optical black pixels while maintaining noise correction capability.
Solution Approach 2:
The readout operation parameters are changed dynamically based on pixel type and position. By controlling whether a pixel performs first readout operation (reading both reset and optical signals) or second readout operation (reading only reset signal), the system can adapt the function of each pixel to optimize both imaging area and noise correction capability.
3Device complexity
If the same readout operation is performed for all pixels, then the device complexity is reduced, but stripe noise and black level emphasis occur
Solution Approach 1:
The readout operation is made dynamic rather than static. Different pixels can perform different readout operations (first or second type) depending on their position and function requirements. This dynamic control allows the system to adapt to different imaging needs and prevent stripe noise and black level emphasis while maintaining manageable device complexity through systematic control line design.
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 allows for high-quality image acquisition with adjusted black levels and reduced stripe noise, even when optical black pixels are not arranged, by effectively managing signal readout and noise suppression across the imaging elements.
Implementation Method 1
a photoelectric converter that generates charge in response to incidence of a light
Data Source
AI summary
A photoelectric conversion element includes pixels that receive light and each generate charge in response to light incidence. The pixels include a first pixel that performs a first readout operation to read a reset signal and an optical signal and a second pixel on which a readout operation is performed at the same time as that of the first pixel and that performs selectively either the first readout operation or a second readout operation to read the reset signal. The photoelectric conversion element further includes, in association with each pixel, a first holding unit that holds the reset signal and the optical signal, and a first switch that controls writing to the first holding unit. A control line that controls the first switch associated with the first pixel and a control line that controls the first switch associated with the second pixel are formed of separate wirings.