Octagon Pixel Array Layout for Low-Light CMOS Imaging
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Solution Overview
Problem
CMOS image sensors suffer from poor image quality in low light conditions due to inadequate capture of red, green, and blue color luminance, leading to issues such as image noise, poor contrast, and poor color saturation.
Innovation Solution
Incorporating a pixel array with interspersed octagon-shaped and square-shaped pixel sensors, including red, green, blue, yellow, NIR, and white pixel sensors to enhance color information capture and improve low light performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional square pixel sensors are used in CMOS image sensors, then the pixel array structure is simple and manufacturing is easier, but the light sensitivity and color saturation are insufficient in low light conditions
Solution Approach 1:
The pixel array is segmented into multiple types of pixel sensors including octagon-shaped pixels, square-shaped pixels, and pixels with different color filters (red, green, blue, yellow, NIR, white). This segmentation allows each pixel type to specialize in capturing specific wavelength ranges or geometric information, thereby improving overall light sensitivity and image quality in low light conditions while managing complexity through functional differentiation
Solution Approach 2:
The patent introduces asymmetric octagon-shaped pixel sensors alongside traditional square pixels. The octagonal geometry provides different light capture characteristics and spatial sampling properties compared to square pixels, enabling improved color saturation and contrast in low light conditions. This asymmetric design breaks the uniformity of traditional pixel arrays to enhance performance
2Measurement precision
If pixel density is increased to improve image quality, then the resolution and detail capture are enhanced, but the manufacturing precision and alignment difficulty increase
Solution Approach 1:
The patent incorporates pixels with different geometric shapes (octagon and square) rather than simply increasing pixel density uniformly. This dimensional variation in pixel geometry allows for enhanced spatial sampling and improved image quality without requiring proportional increases in manufacturing precision, as the shape diversity provides additional degrees of freedom for optimization
3Quantity of substance
If multiple types of pixel sensors (red, green, blue, yellow, NIR, white) are incorporated, then the color information capture and light sensitivity are enhanced, but the device complexity and data processing requirements increase
Solution Approach 1:
The pixel array is designed with multi-functional pixel sensors that can capture different wavelength ranges (visible light, NIR) and provide various imaging functions (color detection, luminance detection, contrast enhancement). Each pixel type serves multiple purposes: for example, yellow pixels contribute to both color saturation and low-light performance, while white pixels provide overall luminance information. This multi-functionality increases light capture capability without proportionally increasing system complexity
Solution Approach 2:
Different regions of the pixel array are assigned different pixel types based on their specific functions. Octagonal pixels may be concentrated in regions requiring enhanced color saturation, while square pixels handle other areas. This local differentiation optimizes the distribution of pixel types to match spatial requirements, improving overall performance while managing complexity through targeted deployment rather than uniform distribution
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
The pixel array configuration increases pixel density, enhances color saturation, improves contrast and contour sharpness, and increases light sensitivity, resulting in improved image quality in low light conditions.
Implementation Method 1
Complementary metal oxide semiconductor (CMOS) image sensors utilize light-sensitive CMOS circuitry, referred to as pixel sensors, to convert light energy into electrical energy. A pixel sensor typically includes a photodiode formed in a silicon substrate. As the photodiode is exposed to light, an electrical charge is induced in the photodiode.
Data Source
AI summary
A pixel array includes octagon-shaped pixel sensors and square-shaped pixel sensors. The octagon-shaped pixel sensors may be interspersed in the pixel array with square-shaped pixel sensors to increase the utilization of space in the pixel array, and to allow for pixel sensors in the pixel array to be sized differently. Moreover, the pixel array may include a combination of red, green, and blue pixel sensors to obtain color information from incident light; yellow pixel sensors for blue and green color enhancement and correction for the pixel array; near infrared (NIR) pixel sensors to increase contour sharpness and low light performance for the pixel array; and/or white pixel sensors to increase light sensitivity and brightness for the pixel array. The capability to configure different sizes and types of pixel sensors permits the pixel array to be formed and/or configured to satisfy various performance parameters.