Image Sensor Sub-Pixel Integration Time Control for Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensors face challenges in achieving a high dynamic range without compromising the frame rate, as techniques to widen the dynamic range often require larger areas or result in decreased frame rates.
Innovation Solution
The image sensor employs a configuration with multiple sub-pixels sharing charge detection nodes, allowing for varying effective integration times to generate sensing signals across different illumination ranges, which are then averaged to enhance the dynamic range while maintaining high-speed binning and frame rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional techniques are used to widen the dynamic range, then the dynamic range is improved, but the frame rate decreases or the area increases
Solution Approach 1:
The pixel array is divided into multiple pixel groups, where each group includes first pixels with a first effective integration time and second pixels with a second effective integration time. This segmentation allows simultaneous capture of multiple exposure times, enabling high dynamic range imaging without reducing frame rate.
Solution Approach 2:
The image sensor alternates between different effective integration times for different pixel groups in a periodic manner. By coordinating the readout timing, the sensor can process multiple exposure frames concurrently, maintaining high frame rate while achieving extended dynamic range through periodic switching between integration time modes.
2Reliability
If multiple sub-pixels with different integration times are used, then the dynamic range is improved, but the device complexity increases
Solution Approach 1:
Each pixel group serves multiple functions by containing both first pixels (with first effective integration time) and second pixels (with second effective integration time). This multi-functional design allows a single pixel group to capture both bright and dark scene details simultaneously, reducing the need for separate pixel types and simplifying the overall device structure.
Solution Approach 2:
The patent merges multiple pixel types with different integration times into unified pixel groups that share common readout circuits and processing pathways. By combining these different pixel types in an integrated manner, the design achieves high dynamic range capability without proportionally increasing device complexity, as the shared infrastructure reduces redundant components.
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 approach enables the image sensor to capture high dynamic range images with improved frame rates and resolution across various illumination conditions without decreasing performance.
Implementation Method 1
a first unit pixel that includes a first sub-pixel and a second sub-pixel, a second unit pixel that includes a third sub-pixel and a fourth sub-pixel
Data Source
AI summary
An image sensor includes a first unit pixel including a first sub-pixel and a second sub-pixel, a second unit pixel including a third sub-pixel and a fourth sub-pixel, a timing controller configured to apply a first effective integration time to the first sub-pixel and the fourth sub-pixel, such that a first sensing signal and a fourth sensing signal are generated from the first sub-pixel and the fourth sub-pixel, respectively, and to apply a second effective integration time shorter than the first effective integration time to the second sub-pixel and the third sub-pixel, such that a second sensing signal and a third sensing signal are generated from the second sub-pixel and the third sub-pixel, respectively, and an analog-to-digital converter configured to perform an averaging operation on the first sensing signal and the fourth sensing signal or on the second sensing signal and the third sensing signal.