Solid-State Image Pickup Device Intermittent Driving Dynamic Range
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Solution Overview
Problem
Existing methods for expanding the dynamic range of solid-state image pickup devices, such as time division, spatial division, and in-pixel memory addition, face limitations including artifacts, reduced image quality, and limited dynamic range expansion due to noise and memory capacity constraints.
Innovation Solution
A solid-state image pickup device with a pixel array unit and a driving unit that changes the sensitivity ratio of photoelectric conversion sections through intermittent driving, allowing for arbitrary control of sensitivity ratios, thereby expanding the dynamic range without physical sensitivity differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time division method is used to expand dynamic range by increasing the number of divisions, then dynamic range is improved, but artifacts occur
Solution Approach 1:
The pixel array is divided into multiple pixel groups, each with different sensitivity characteristics. This segmentation allows simultaneous capture of multiple sensitivity levels within a single exposure, expanding dynamic range without the temporal artifacts caused by time division methods.
Solution Approach 2:
The patent transitions from time-based division to spatial-based division by arranging pixels with different sensitivities in different spatial locations within the same exposure period. This dimensional change eliminates temporal artifacts while maintaining dynamic range expansion capability.
2Adaptability or versatility
If spatial division method is used to expand dynamic range by increasing the number of divisions, then dynamic range is improved, but image quality is deteriorated due to reduction in resolution
Solution Approach 1:
Each pixel group serves multiple functions: they collectively capture the full dynamic range while individual groups maintain their original sensitivity characteristics. This allows the system to preserve image quality for different brightness regions simultaneously without reducing overall resolution.
Solution Approach 2:
Different pixel groups are assigned different sensitivity characteristics appropriate for their local brightness requirements. This local optimization allows each region to contribute to the overall image quality while collectively achieving expanded dynamic range.
3Adaptability or versatility
If in-pixel memory addition method is used to expand dynamic range, then dynamic range is improved, but there is a limit due to memory capacity
Solution Approach 1:
Instead of storing multiple charge values in memory, the patent creates multiple simultaneous measurements by using pixel groups with different sensitivities. This copying approach captures different brightness levels in parallel, eliminating the need for additional memory capacity while achieving the same dynamic range expansion effect.
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 flexible dynamic range adjustment and prevents artifacts and resolution reduction associated with other methods, while maintaining high image quality by controlling sensitivity ratios through intermittent driving.
Implementation Method 1
a pixel array unit, unit pixels being arranged in the pixel array unit, the unit pixels each including a plurality of photoelectric conversion sections
Data Source
AI summary
A solid-state image pickup device according to the present disclosure includes: a pixel array unit, unit pixels being arranged in the pixel array unit, the unit pixels each including a plurality of photoelectric conversion sections; and a driving unit that changes a sensitivity ratio of the plurality of photoelectric conversion sections by performing intermittent driving with respect to storing of signal charges of the plurality of photoelectric conversion sections. That is, the solid-state image pickup device according to the present disclosure changes a sensitivity ratio of the plurality of photoelectric conversion sections by performing intermittent driving with respect to storing of signal charges of the plurality of photoelectric conversion sections.