Dual-Sensitivity Pixel Structure for High Dynamic Range Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional CMOS image sensors have a limited dynamic range, which makes it difficult to capture both strong and weak light information simultaneously, leading to misjudgment in environments like traffic signs with high flickering frequencies, resulting in potential traffic accidents.
Innovation Solution
A pixel structure comprising a first photoelectric conversion element with high sensitivity for weak light and a second photoelectric conversion element with low sensitivity for strong light, along with a reading circuit to transfer and read signals from both elements, improving the dynamic range and accuracy of the image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single photoelectric conversion element is used, then the device complexity is low, but the dynamic range is limited
Solution Approach 1:
The pixel structure is divided into two separate photoelectric conversion elements: a first photoelectric conversion element for capturing weak light and a second photoelectric conversion element for capturing strong light. This segmentation allows each element to be optimized for its specific light intensity range, thereby expanding the overall dynamic range of the image sensor without significantly increasing device complexity
Solution Approach 2:
Different photoelectric conversion elements are designed with different local qualities optimized for specific functions. The first photoelectric conversion element has characteristics optimized for weak light detection, while the second photoelectric conversion element has characteristics optimized for strong light detection. This local quality differentiation enables the system to handle a wider range of light intensities effectively
2Reliability
If multiple photoelectric conversion elements with different sensitivities are used, then the dynamic range is improved, but the device complexity increases
Solution Approach 1:
Multiple photoelectric conversion elements with different sensitivities are merged into a single integrated pixel structure. The first photoelectric conversion element and the second photoelectric conversion element are combined within the same pixel unit, sharing common circuitry such as the transfer transistor and floating diffusion region. This merging approach expands the dynamic range while controlling the increase in device complexity through resource sharing
Solution Approach 2:
The pixel structure is designed with multi-functionality, where the same transfer transistor and floating diffusion region serve both the first photoelectric conversion element and the second photoelectric conversion element. This universal design allows the system to handle both weak light and strong light scenarios using a single integrated structure, improving dynamic range without proportionally increasing device complexity
3Device complexity
If standard dynamic range sensors are used, then the device complexity is low, but the ability to capture both strong and weak light simultaneously is limited
Solution Approach 1:
The image sensor implements dynamic adaptability by enabling selective activation of different photoelectric conversion elements based on the incident light intensity. The system can dynamically switch between using only the first photoelectric conversion element for weak light, only the second photoelectric conversion element for strong light, or both simultaneously for intermediate conditions. This dynamic operation expands the adaptability to different light intensity ranges while maintaining relatively low device complexity
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 enhances the dynamic range of the image sensor, allowing it to effectively capture both strong and weak light information, reducing signal noise and improving reading accuracy, thereby preventing misjudgments in various applications.
Implementation Method 1
a first photoelectric conversion element, a first transfer transistor, coupled to a first floating diffusion region, for transferring charges in the first photoelectric conversion element to the first floating diffusion region; a second photoelectric conversion element, the sensitivity of the second photoelectric conversion element is lower than that of the first photoelectric conversion element
Data Source
AI summary
A pixel structure, an image sensor, an electronic device and a method for controlling an image sensor are provided. The pixel structure includes a plurality of pixel units arranged in an array, each pixel unit includes a first photoelectric conversion element; first transfer transistor, coupled to a first floating diffusion region, for transferring charges in the first photoelectric conversion element to the first floating diffusion region; a second photoelectric conversion element, where the sensitivity of the second photoelectric conversion element is lower than that of the first photoelectric conversion element; a second transfer transistor, coupled to a second floating diffusion region, for transferring charges in the second photoelectric conversion element to the second floating diffusion region; and a reading circuit, coupled to the first floating diffusion region and the second floating diffusion region, for reading voltage signals of the first floating diffusion region and the second floating diffusion region.