Net-Shape Wiring Layout for Wide-Dynamic-Range Image Sensors
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Solution Overview
Problem
Imaging devices using CMOS sensors require improved dynamic range and low power consumption to enable imaging in various environments and extend continuous operating time, particularly in portable devices like mobile phones.
Innovation Solution
The imaging device incorporates a photoelectric conversion element with n-type and p-type semiconductors, transistors, and capacitors, utilizing oxide semiconductors with specific wiring configurations to enhance dynamic range and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CMOS imaging sensors are used, then manufacturing cost is low and resolution is high, but dynamic range is insufficient for imaging under various environments
Solution Approach 1:
The imaging device is segmented into multiple pixel types (first pixels with first photoelectric conversion elements and second pixels with second photoelectric conversion elements) within the same photoelectric conversion unit. This segmentation allows different pixel types to handle different light intensity ranges, thereby expanding the overall dynamic range without significantly increasing device complexity
Solution Approach 2:
Different photoelectric conversion elements are assigned to different regions or functions within the imaging device. Specifically, first photoelectric conversion elements are used in first pixels while second photoelectric conversion elements are used in second pixels, allowing each region to have optimized characteristics for its specific function (e.g., high sensitivity for low light, high linearity for bright light)
2Reliability
If imaging device operates continuously to capture images in various environments, then image quality is maintained, but power consumption increases and operating time shortens
Solution Approach 1:
The imaging device dynamically switches between different photoelectric conversion elements based on lighting conditions. First photoelectric conversion elements are used under certain light conditions while second photoelectric conversion elements are used under other conditions, allowing the device to adapt to varying environments and maintain image quality while optimizing power consumption by activating only the necessary pixel types
3Adaptability or versatility
If more photoelectric conversion elements are added to improve dynamic range, then imaging capability in various environments is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The imaging device uses a dual pixel structure where both first and second photoelectric conversion elements can function across different lighting conditions. This multi-functionality allows the device to achieve expanded dynamic range and improved imaging capability in various environments while maintaining a manageable manufacturing process, as both pixel types follow similar fabrication steps
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 provides an imaging device with improved dynamic range, better image quality, reduced power consumption, and increased productivity, while maintaining high sensitivity and reliability.
Implementation Method 1
a photoelectric conversion element, first to fourth transistors, a capacitor, and first to seventh wirings
Data Source
AI summary
A solid-state imaging device with high productivity and improved dynamic range is provided. In the imaging device including a photoelectric conversion element having an i-type semiconductor layer, functional elements, and a wiring, an area where the functional elements and the wiring overlap with the i-type semiconductor in a plane view is preferably less than or equal to 35%, further preferably less than or equal to 15%, and still further preferably less than or equal to 10% of the area of the i-type semiconductor in a plane view. Plural photoelectric conversion elements are provided in the same semiconductor layer, whereby a process for separating the respective photoelectric conversion elements can be reduced. The respective i-type semiconductor layers in the plural photoelectric conversion elements are separated by a p-type semiconductor layer or an n-type semiconductor layer.