Pixel Array with Long and Short Exposure Groups for High Dynamic Range
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Solution Overview
Problem
The reduction in pixel size of CMOS image sensors leads to performance deterioration, and achieving a high dynamic range to capture fine images on both dark and bright screens while maintaining resolution is challenging.
Innovation Solution
A pixel array is designed with a combination of long and short exposure pixels, including a white component, where each pixel group consists of one long exposure pixel and multiple short exposure pixels, arranged in a specific pattern to enhance dynamic range and sensitivity, with electrical connections between pixels for improved resolution modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to increase resolution, then the number of pixels increases, but sensing performance deteriorates
Solution Approach 1:
The pixel array is segmented into multiple types of pixels (long exposure pixels and short exposure pixels) within each pixel group, allowing different pixels to specialize in different exposure conditions. This segmentation enables each pixel type to optimize its performance for specific scenarios, preventing the uniform degradation that occurs when all pixels are simply miniaturized.
Solution Approach 2:
Different regions of the pixel array have different pixel characteristics - long exposure pixels are positioned to capture dim scenes while short exposure pixels capture bright scenes. This local differentiation of pixel quality allows the system to maintain high sensing performance across varying lighting conditions without requiring all pixels to be large.
2Adaptability or versatility
If high dynamic range is achieved through multiple exposure times, then image quality on dark and bright screens improves, but device complexity increases
Solution Approach 1:
The patent merges long exposure pixels and short exposure pixels into integrated pixel groups that share common circuitry and control structures. This combining approach achieves high dynamic range functionality while reducing the overall device complexity compared to having completely separate exposure systems.
Solution Approach 2:
Each pixel group serves multiple functions by containing both long exposure and short exposure pixels, allowing the same structural unit to handle various lighting conditions. This multi-functionality reduces device complexity by eliminating the need for separate specialized systems for different exposure requirements.
3Reliability
If white pixels are added to improve sensitivity, then sensing capability increases, but color information accuracy may be compromised
Solution Approach 1:
The patent uses color conversion circuits as intermediaries that process the signals from white pixels and convert them into color information. This intermediary mechanism allows white pixels to provide high sensitivity while the color conversion process restores color accuracy, resolving the contradiction between sensitivity and color precision.
Solution Approach 2:
The system employs color conversion technology that transforms the broadband signal from white pixels into specific color channel information. This color change process enables white pixels to contribute to both sensitivity enhancement and color image formation, eliminating the trade-off between sensitivity and color accuracy.
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 improves sensing sensitivity and dynamic range, effectively addressing performance deterioration and enabling high-quality image capture across varying brightness levels without compromising resolution.
Implementation Method 1
The light detection element may generate an electrical signal according to the intensity of absorbed light
Data Source
AI summary
A pixel array to which a high dynamic range and a white pixel are applied, and an image sensor including the same are provided. The pixel array of the image sensor includes: a plurality of pixel groups, each pixel group including one or more long exposure pixels and one or more short exposure pixels, wherein each pixel group includes a first pixel, among the one or more long exposure pixels and the one or more short exposure pixels, having a white component and second to fourth pixels, among the one or more long exposure pixels and the one or more short exposure pixels, having first to third color components, the first pixel belonging to a first pixel group is a long exposure pixel, and the first pixel belonging to a second pixel group that is adjacent to the first pixel group is a short exposure pixel.