Dual-Cell Imaging Pixel Layout for Wide Dynamic Range
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Solution Overview
Problem
Conventional imaging devices face challenges in achieving wide dynamic range imaging without compromising concurrency and increasing pixel size, as they require multiple pixel cells with reduced sensitivity and saturation electrons, leading to inferior pixel cell characteristics and noise issues.
Innovation Solution
The implementation of an imaging device with two pixel cells per pixel, where one cell is optimized for low-noise high-sensitivity imaging and the other for high-saturation low-sensitivity imaging, using different signal processing circuits and capacitive elements to manage noise and saturation, allowing for concurrent imaging of bright and dark scenes without pixel size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple pixel cells with different sensitivity are used to achieve wide dynamic range, then dynamic range is improved, but pixel cell characteristics deteriorate and noise increases
Solution Approach 1:
The imaging device divides each pixel into multiple pixel cells (first pixel cell with larger area for high sensitivity, second pixel cell with smaller area for low sensitivity). This segmentation allows different cells to specialize in different brightness ranges, achieving wide dynamic range while maintaining optimal characteristics in each cell without the noise and performance degradation seen in conventional multi-cell approaches.
2Adaptability or versatility
If conventional multi-pixel cell approach is used, then dynamic range is widened, but saturation electrons are reduced leading to inferior imaging characteristics
Solution Approach 1:
The patent applies local quality by giving different areas (pixel cells) different characteristics: the first pixel cell has larger area and higher saturation electron capacity for capturing dark scenes, while the second pixel cell has smaller area and lower saturation electron capacity for capturing bright scenes. This local differentiation allows each cell to operate optimally in its designated brightness range, maintaining high saturation electron counts where needed without compromising overall dynamic range.
3Measurement precision
If pixel size is increased to improve sensitivity, then sensitivity is improved, but device area increases
Solution Approach 1:
The patent transitions from a single-dimensional approach (one pixel size for all conditions) to a multi-dimensional approach by dividing each pixel into multiple cells with different areas. The first pixel cell has larger area for high sensitivity in dark conditions, while the second pixel cell has smaller area for bright conditions. This dimensional transformation allows the system to achieve high sensitivity where needed without increasing the overall pixel footprint, as both cells share the same physical pixel space.
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 enables wide dynamic range imaging without time lag, preventing blown out highlights and blocked up shadows, while maintaining high sensitivity and low noise levels, thus achieving desirable pixel cell characteristics.
Implementation Method 1
a first photoelectric converter that generates a first signal by photoelectric conversion; and a second photoelectric converter that generates a second signal by photoelectric conversion
Data Source
AI summary
An imaging device including: a first imaging cell including a first photoelectric converter that generates a first signal; and a second imaging cell including: a second photoelectric converter that generates a second signal; and a capacitor having a first and second terminal, the first terminal electrically coupled to second photoelectric converter. An area of the first photoelectric converter is greater than an area of the second photoelectric converter in a plan view, the first imaging cell has a first number of saturation charges, and the second imaging cell has a second number of saturation charges, the first number of saturation charges is greater than the second number of saturation charges, and the capacitor has capacitance that causes the second number of saturation charges of the second imaging cell to become greater than the first number of saturation charges of the first imaging cell.