Stacked Diffraction-Absorption Pixel Structure for Color Filtering
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Solution Overview
Problem
The reduction in pixel size of CMOS image sensors for high-resolution images results in low filtering efficiency and reduced sensing contrast and color performance due to thinner color filters.
Innovation Solution
A solid-state image sensor design that stacks a diffraction layer with diffraction elements and an absorption layer, where each pixel is defined by corresponding gaps in both layers, enhancing signal-to-noise ratio (SNR) performance and transmittance by optimizing the arrangement and materials of these layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to increase the number of pixels for high-resolution images, then the resolution is improved, but the color filter thickness is reduced resulting in low filtering efficiency and reduced sensing contrast
Solution Approach 1:
The color filter layer is segmented into multiple independent layers (first color filter layer, second color filter layer, third color filter layer) with different spectral characteristics. Each layer filters specific wavelength ranges, and their combined effect provides superior color separation and filtering efficiency that cannot be achieved with a single thin layer, thereby resolving the contradiction between high resolution and color performance.
Solution Approach 2:
The patent employs composite material structures by combining multiple color filter layers with different material compositions and spectral transmission characteristics. This composite approach enables each layer to contribute its unique filtering properties, achieving high filtering efficiency and sensing contrast while maintaining the reduced pixel size required for high-resolution imaging.
2Measurement precision
If the pixel size is reduced to increase the number of pixels, then the resolution is improved, but the filtering efficiency is reduced due to thinner color filters
Solution Approach 1:
The color filter layer is segmented into multiple independent layers (first color filter layer, second color filter layer, third color filter layer) with different spectral characteristics. Each layer filters specific wavelength ranges, and their combined effect provides superior color separation and filtering efficiency that cannot be achieved with a single thin layer, thereby resolving the contradiction between high resolution and color performance.
Solution Approach 2:
Instead of increasing the thickness of a single color filter layer in the vertical dimension, the patent transitions to a multi-layer stacked architecture, adding complexity in the layering dimension. This dimensional change allows each layer to be optimized for specific wavelength filtering while collectively achieving high filtering efficiency within the constrained pixel size.
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 stacked design improves SNR and transmittance, addressing the issues of low filtering efficiency and color performance in high-resolution image sensors.
Implementation Method 1
A solid-state image sensor design that stacks a diffraction layer with diffraction elements
Implementation Method 2
an absorption layer... disposed below the diffraction layer and includes absorption elements
Data Source
AI summary
A solid-state image sensor is provided. The solid-state image sensor includes a diffraction layer and an absorption layer. The diffraction layer includes diffraction elements that have top central gaps, and the absorption layer is disposed below the diffraction layer and includes absorption elements that have bottom central gaps. Pixels of the solid-state image sensor are defined by the diffraction elements, the pixels are arranged in an array, and the absorption elements. Each top central gap corresponds to one bottom central gap and one pixel.