Meta Surface Image Sensor for Low-Light Color Routing
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Solution Overview
Problem
Conventional image sensors face challenges in enhancing quantum efficiency and reducing color errors, especially in low luminance environments, due to the use of less-absorbing or non-absorbing materials in color filter units, which lead to increased power consumption and color noise during signal processing.
Innovation Solution
Incorporating a meta surface with nanostructures that act as a color router, splitting incident light rays by generating a phase library, allowing only desired colors to reach corresponding sensor units, thereby eliminating the need for signal conversion and reducing power consumption and color errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If less-absorbing or non-absorbing materials are used for color filter units, then light sensitivity is enhanced, but color-channel imbalance and color noise increase
Solution Approach 1:
The patent introduces a meta surface with nanostructures as an intermediary component between the color filter layer and the sensor units. This meta surface acts as a color router that separates incident light by wave bands and directs different colors to appropriate sensor units, thereby compensating for the color accuracy loss caused by using less-absorbing filter materials while maintaining their high light sensitivity advantage
Solution Approach 2:
The patent applies local quality by creating spatially varying optical properties through the meta surface nanostructures. Different regions of the meta surface have different nanostructure configurations that selectively route specific wavelength ranges to specific sensor units, enabling localized color management that compensates for the broadband transmission of less-absorbing filters
2Illumination intensity
If less-absorbing or non-absorbing materials are used for color filter units, then light sensitivity is enhanced, but power consumption increases
Solution Approach 1:
The meta surface with color routing capability serves as an intermediary that performs optical sorting before light reaches the sensor units. This physical separation of wavelengths reduces the computational burden on the image signal processor, thereby reducing power consumption while maintaining the high light sensitivity enabled by less-absorbing filter materials
Solution Approach 2:
The patent replaces computational color correction (software/image processing approach) with physical optical sorting (hardware/meta surface approach). By using nanostructures to physically separate and route different wavelengths to appropriate sensors, the system reduces reliance on power-intensive post-processing algorithms
3Manufacturing precision
If standard Bayer mosaic pattern with green color filter units is used, then color accuracy is maintained, but light sensitivity is reduced in low luminance environments
Solution Approach 1:
The patent segments the optical path by using the meta surface to divide incident light into different wavelength bands and direct them to specialized sensor units. This segmentation allows each sensor unit to optimize for specific wavelength ranges, achieving both high light sensitivity and color accuracy that cannot be obtained with a standard Bayer pattern alone
Solution Approach 2:
The patent adds a new dimension to color filtering by introducing the meta surface layer with vertical nanostructures above the traditional planar color filter layer. This third-dimensional optical element enables wavelength-selective routing that complements the spectral filtering of the color filter materials, achieving superior performance in both sensitivity and accuracy
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 meta surface enhances quantum efficiency by minimizing optical energy loss and power consumption, while reducing color errors and improving image quality, especially in low luminance conditions.
Implementation Method 1
a meta surface with nanostructures to act as a color router, separating incident light rays by wave bands and directing them to corresponding sensor units
Data Source
AI summary
An image sensor includes groups of sensor units, and a color filter layer having color units that disposed within the groups of sensor units, respectively. The color units of the color filter layer include a yellow color unit or a white color unit. The image sensor further includes a dielectric structure disposed on the color filter layer, and a meta surface disposed on the dielectric structure.