HDR Image Sensor Pixel Layout for Reduced Crosstalk and Jaggy
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Solution Overview
Problem
High dynamic range image sensors face challenges with crosstalk and jaggy artifacts due to varying transmissivity of color filters, which affect image quality and dynamic range.
Innovation Solution
The implementation of a pixel array structure with sub-pixels having different transmissivity levels, where each pixel is divided into SPD and LPD sub-pixels, allows for varied exposure conditions and interpolation calculations to correct sampling positions, reducing crosstalk and jaggy issues while maintaining uniform intervals for improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the transmissivity of the color filter is increased to improve light reception, then the amount of light received increases, but charge overflow and crosstalk occur
Solution Approach 1:
Each pixel is divided into multiple sub-pixels (first photoelectric conversion cells and second photoelectric conversion cells) with different color filter transmissivities. This segmentation allows different sub-pixels to capture light at different sensitivity levels, preventing charge overflow in high-transmissivity regions while maintaining good light reception overall.
Solution Approach 2:
Different sub-pixels within the same pixel are assigned different color filter transmissivity characteristics. Some sub-pixels have high transmissivity for better light reception, while others have low transmissivity to prevent charge overflow. This local differentiation of quality resolves the contradiction between light reception and crosstalk prevention.
2Adaptability or versatility
If sub-pixels with different transmissivity are placed adjacent to each other to achieve HDR, then dynamic range improves, but sampling position deviations cause jaggy artifacts
Solution Approach 1:
The patent introduces a new dimension of photoelectric conversion cell size differentiation in addition to transmissivity variation. First photoelectric conversion cells have smaller areas while second photoelectric conversion cells have larger areas. This area dimension, combined with transmissivity differentiation, allows for more precise control of sampling positions and reduces jaggy artifacts while maintaining HDR capability.
Solution Approach 2:
The patent changes multiple parameters simultaneously: color filter transmissivity (high vs. low), photoelectric conversion cell area (small vs. large), and exposure periods (different durations). By coordinating changes in these parameters, the patent achieves HDR imaging while correcting sampling position deviations to prevent jaggy artifacts.
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 enhances image quality by reducing crosstalk and jaggy artifacts, enabling wider dynamic range and accurate representation of both bright and dark areas without blown highlights or blocked shadows.
Implementation Method 1
an amount of light reception at a cell which receives transmitted light with a high transmissivity becomes large, resulting in a large amount of charges caused by a photoelectric conversion
Data Source
AI summary
An image sensor has a plurality of pixels arranged in a row direction and in a column direction. Each pixel comprises a color filter that has a portion with a low transmissivity and a portion with a high transmissivity, and a photoelectric conversion element that includes a first photoelectric conversion cell which receives light transmitting through the portion with the low transmissivity of the color filter, and a second photoelectric conversion cell which receives light transmitting through the portion with the high transmissivity of the color filter. The plurality of pixels are arranged such that positions of the portions with the low transmissivity for pixels of one color are identical among the plurality of pixels, and the portions with the low transmissivity are positioned adjacent to each other between adjacent pixels of different colors in the row direction only.