Metasurface Image Sensor Layout for Pixel-Level Wavelength Separation
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Solution Overview
Problem
Conventional image sensors face challenges in achieving sufficient wavelength separation and quantum efficiency due to reduced pixel size, leading to uneven light reception and color variations, especially in low luminance conditions.
Innovation Solution
Incorporating a metasurface with nanostructures, including peripheral and central nanoposts, to guide different incident wavelengths to their corresponding sensor units, optimizing dimensions and pitches using an algorithm, and adjusting central nanopost positions to enhance phase distribution and reduce optical energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sensor unit size is reduced to increase pixel density, then productivity and resolution are improved, but wavelength separation capability deteriorates due to insufficient diffraction/refraction effectiveness
Solution Approach 1:
The patent changes the physical parameters of the light-matter interaction by using nanoposts with specific diameters (50-200nm) and heights (200-500nm), and by adjusting the refractive index of the metasurface material. These parameter changes enable effective wavelength separation even at reduced sensor unit sizes where conventional diffraction and refraction become insufficient.
Solution Approach 2:
The patent employs composite material structures by combining the metasurface layer with the color filter layer and sensor units. The metasurface itself is composed of nanoposts made from materials with specific refractive indices, creating a composite optical system that enhances wavelength separation capability while maintaining compact sensor unit dimensions.
2Device complexity
If conventional metasurface design is used with reduced sensor units, then device complexity is maintained, but quantum efficiency deteriorates due to uneven light reception and optical energy loss
Solution Approach 1:
The patent applies local quality by positioning specific nanoposts at corner locations of the sensor unit and using different nanopost configurations in different regions. This localized optimization ensures that light reception is evenly distributed across all sensor units, preventing optical energy loss and improving quantum efficiency without requiring a complete redesign of the entire metasurface structure.
Solution Approach 2:
The patent performs preliminary wavelength separation at the metasurface level before light reaches the sensor units. By pre-separating wavelengths and directing them to appropriate sensor units through the nanopost array, the system prevents uneven light reception and maximizes quantum efficiency before the light detection process begins.
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 metasurface configuration improves quantum efficiency by minimizing optical energy loss and ensuring uniform light reception across pixels, enabling better performance in low-light conditions and broader energy applications.
Implementation Method 1
The incident wavelengths may be separated via diffraction or refraction characteristics of light
Implementation Method 2
The incident wavelengths may be separated via diffraction or refraction characteristics of light
Implementation Method 3
the transmitting directions of the separated wavelengths may be adjusted according to the refractive indices and shapes of the metasurface
Data Source
AI summary
An image sensor includes a group of sensor units, a color filter layer disposed within the group of sensor units, and a dielectric structure and a metasurface disposed corresponding to the color filter layer. The metasurface includes a plurality of peripheral nanoposts located at corners of the group of sensor units from top view, respectively, a central nanopost enclosed by the plurality of peripheral nanoposts, and a filling material laterally surrounding the plurality of peripheral nanoposts and the central nanopost. The central nanopost is offset from a center point of the group of sensor units by a distance from top view.