CMOS Image Sensor Color Filter Layout for Sensitivity and Sharpness
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Solution Overview
Problem
Existing CMOS image sensors face challenges in achieving optimal optical characteristics, such as pixel sensitivity and image sharpness, while maintaining compatibility with CMOS process technology and minimizing power consumption.
Innovation Solution
The proposed image sensor incorporates a color filter array with a specific configuration of two yellow, one cyan, and one red color filters arranged in a two-by-two array, which enhances optical characteristics by optimizing light transmission and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional primary color filter array (RGB) is used, then the image sensor can achieve good color reproduction, but the pixel sensitivity and image sharpness are limited
Solution Approach 1:
The patent changes the spectral transmission parameters of the color filters by using two yellow filters, one cyan filter, and one red filter instead of the traditional RGB configuration. This parameter change in the filter wavelengths and arrangement improves pixel sensitivity while maintaining manageable device complexity
Solution Approach 2:
The patent creates a composite color filter array structure by combining different types of color filters (yellow, cyan, red) in a specific two-by-two pattern. This composite approach allows the system to achieve superior optical characteristics by leveraging the complementary properties of different filter materials
2Measurement precision
If a complementary color filter array (CMY) is used, then the pixel sensitivity can be improved, but the image sharpness and color accuracy deteriorate
Solution Approach 1:
The patent applies local quality by having different color filters in different positions within the two-by-two array. The specific arrangement of yellow, cyan, and red filters at different locations allows each filter to optimize for its local function while contributing to overall image sharpness and color accuracy
Solution Approach 2:
The patent segments the color filter array into a two-by-two configuration with distinct filter types in each position. This segmentation allows independent optimization of each filter's contribution to sensitivity while maintaining overall image quality through the specific combinatorial arrangement
3Measurement precision
If the color filter array is optimized for maximum light transmission, then pixel sensitivity improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent achieves universality by designing a color filter array that serves multiple functions simultaneously: the two yellow filters, one cyan filter, and one red filter work together to provide both enhanced light transmission for sensitivity and maintain compatibility with existing CMOS manufacturing processes, avoiding the need for entirely new fabrication techniques
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 improves pixel sensitivity and image sharpness compared to traditional primary and complementary color filter arrays, while maintaining the advantages of CMOS image sensors such as low power consumption and cost-effective manufacturing.
Implementation Method 1
enhances optical characteristics by optimizing light transmission and sensitivity
Implementation Method 2
a color filter unit including four color filters that are arranged in a two-by-two array
Data Source
AI summary
Image sensors are provided. The image sensors may include a plurality of unit pixels and a color filter array on the plurality of unit pixels. The color filter array may include a color filter unit including four color filters that are arranged in a two-by-two array, and the color filter unit may include two yellow color filters, a cyan color filter, and one of a red color filter or a green color filter.