Semiconductor Imaging Pixel Bank Segmentation for Dynamic Range and Power
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Solution Overview
Problem
Solid-state imaging devices with CMOS sensors face challenges in improving dynamic range, image quality, and reducing power consumption, especially in low-light environments and when capturing fast-moving objects, due to limitations in exposure time and photodiode size.
Innovation Solution
A method for driving a semiconductor device with specific transistor configurations and photoelectric conversion elements, utilizing oxide semiconductors to enhance the dynamic range and reduce power consumption, allowing for improved image capturing in various environments and faster image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure time is extended to improve dynamic range in low-light environments, then image quality improves, but image distortion occurs when objects move or the device moves during exposure
Solution Approach 1:
The image sensor divides the pixel array into multiple banks, where each bank can independently perform photoelectric conversion and charge accumulation. This segmentation allows different exposure times for different regions, enabling the system to capture images in low-light conditions without causing distortion in moving objects, as each bank can be controlled independently to avoid the distortion issue while maintaining dynamic range improvement.
Solution Approach 2:
The patent implements a global shutter mechanism with multiple banks that can dynamically adjust their operation modes. The system can switch between different exposure strategies for different banks based on scene requirements, allowing dynamic range improvement in static regions while preventing distortion in moving regions through coordinated control of the multiple banks.
2Area of moving object
If photodiode size is reduced to increase pixel density, then device integration improves, but light reception capability deteriorates in low-light environments
Solution Approach 1:
The patent combines multiple photodiodes within each pixel bank to form a consolidated photoelectric conversion unit. By merging the light reception capability of multiple smaller photodiodes while maintaining high pixel density through the multi-bank architecture, the system achieves both high integration and improved light reception capability for low-light environments.
3Device complexity
If rolling shutter method is used to simplify the driving method, then device complexity reduces, but image capturing duration increases and dynamic range improvement is limited
Solution Approach 1:
The patent segments the pixel array into multiple banks that can operate independently with different timing. This segmentation enables the system to capture images from different banks simultaneously or with staggered timing, significantly reducing the total image capturing duration compared to sequential row-by-row reading in rolling shutter methods, while maintaining relatively simple driving circuitry.
4Manufacturing precision
If more transistors are added per pixel to improve photoelectric conversion efficiency, then image quality improves, but power consumption increases
Solution Approach 1:
The patent divides the pixel array into multiple banks with independent photoelectric conversion circuits. This segmentation allows the system to activate only the necessary banks based on scene requirements, reducing overall power consumption while maintaining high photoelectric conversion efficiency in active regions. The independent bank structure enables selective operation that balances efficiency and power usage.
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
The solution enables solid-state imaging devices with improved dynamic range, enhanced image quality, and reduced power consumption, enabling efficient image capture in low-light conditions and fast-moving object imaging while minimizing power usage.
Implementation Method 1
a first photoelectric conversion element, a first transistor, a second transistor, and a third transistor... a first potential corresponding to the amount of light received by the second photoelectric conversion element is written to the first node
Data Source
AI summary
To provide a solid-state imaging device with short image-capturing duration. A first photodiode in a pixel in an n-th row and an m-th column is connected to a second photodiode in a pixel in an (n+1)-th row and the m-th column through a transistor. The first photodiode and the second photodiode receive light concurrently, the potential in accordance with the amount of received light is held in a pixel in the n-th row and the m-th column, and the potential in accordance with the amount of received light is held in a pixel in the (n+1)-th row and the m-th column without performing a reset operation. Then, each potential is read out. Under a large amount of light, either the first photodiode or the second photodiode is used.