Minimal Repeating Pixel Array for Low-Crosstalk Color Imaging
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Solution Overview
Problem
Image sensor pixel arrays with clear pixels suffer from increased crosstalk, leading to low color performance, necessitating a design without clear pixels to enhance sensitivity and color accuracy.
Innovation Solution
A minimal repeating unit pixel array configuration is implemented, comprising a pattern of red, green, blue, and clear pixels, where clear pixels are eliminated, and the array is arranged to achieve full resolution through interpolation and demosaicing, utilizing a higher percentage of green pixels for improved color performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If clear pixels are used to increase sensitivity, then light sensitivity is improved, but crosstalk increases leading to poor color performance
Solution Approach 1:
The patent removes clear pixels from the pixel array entirely, extracting the problematic element that causes crosstalk while maintaining color filter pixels that provide accurate color information. This extraction resolves the contradiction by eliminating the source of crosstalk while preserving the color accuracy function.
Solution Approach 2:
The patent implements a pixel array where all pixels are color filter pixels that can function for both color imaging and depth map generation. This multi-functionality eliminates the need for separate clear pixels, resolving the contradiction by making all pixels universally useful for both color and depth applications.
2Illumination intensity
If clear pixels are used to enhance sensitivity, then low light performance is improved, but color performance deteriorates
Solution Approach 1:
The patent extracts and removes clear pixels from the array, retaining only color filter pixels that maintain color accuracy while the microlens structure provides the necessary light gathering capability for low light performance without sacrificing color information.
Solution Approach 2:
The patent changes the optical parameters by introducing microlenses over color filter pixels to enhance light gathering capability. This parameter change allows color filter pixels to achieve the light sensitivity previously only available from clear pixels, resolving the contradiction between low light performance and color performance.
3Power
If clear pixels are used to increase sensitivity, then signal strength is improved, but crosstalk increases
Solution Approach 1:
The patent extracts clear pixels that generate crosstalk from the pixel array, leaving only color filter pixels. The signal strength is maintained through microlens enhancement and pixel binning techniques, while the harmful crosstalk effect is completely eliminated by removing the source pixels.
Solution Approach 2:
The patent converts the potential harm of reduced pixel count (from removing clear pixels) into a benefit by implementing pixel binning and microlens enhancement. These techniques concentrate light onto fewer effective pixels, increasing signal strength while maintaining color accuracy, thus converting what could be a disadvantage into an advantage.
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 color performance and resolution by eliminating clear pixels, reducing crosstalk, and utilizing a higher percentage of green pixels for luminance representation, resulting in better image quality and sensitivity, particularly in low-light conditions.
Implementation Method 1
each pixel of the minimal repeating unit has a microlens
Implementation Method 2
a pixel array having a minimal repeating unit... each pixel in the pixel array is coupled to a filter
Data Source
AI summary
In an embodiment, an image sensor comprises a pixel array having a minimal repeating unit, where the minimal repeating unit consists of 4×4 pixels including 12 green pixels, 2 blue pixels, and 2 red pixels, where a minimal repeating unit is immediately next to another minimal repeating unit in row and column directions. In another embodiment, an image sensor comprises a pixel array having a minimal repeating unit, where the minimal repeating unit consists of 8×8 pixels including 48 green pixels, 8 blue pixels, and 8 red pixels.