Metasurface Image Sensor for Multi-Band Color Capture
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Solution Overview
Problem
Conventional image sensors using Bayer color filters suffer from low light utilization, as more than 70% of optical signals are filtered out, leading to reduced imaging quality and color distortion due to the limited number of spectral channels.
Innovation Solution
The implementation of metasurface structures with rotationally symmetric microstructures and spatial transmission phase gradients to split and transmit optical signals across multiple frequency bands to corresponding optical-to-electrical conversion elements, replacing traditional light filtering with a light splitting manner, thereby improving light transmittance and utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Bayer color filter system is used to obtain color information, then color picture quality is improved, but light utilization deteriorates because more than 70% of light is filtered out
Solution Approach 1:
The patent divides the optical signal processing into multiple frequency bands using metasurface structures with different microstructure types. Each microstructure type corresponds to a specific frequency band and directs it to a dedicated optical-to-electrical conversion element, enabling simultaneous capture of multiple color channels without filtering out excess light.
Solution Approach 2:
The patent changes the structural parameters of the metasurface microstructures (shape, size, orientation) to create frequency-selective transmission characteristics. By adjusting these parameters, different frequency bands are directed to appropriate conversion elements, achieving color separation without traditional filtering losses.
2Measurement precision
If a Bayer color filter system is used to separate spectral channels, then color differentiation is improved, but the quantity of light reaching conversion elements deteriorates
Solution Approach 1:
The patent transitions from the traditional two-dimensional color filter array to a three-dimensional metasurface structure with spatially varying microstructures. This adds a structural dimension for controlling light propagation, enabling frequency-based spatial separation while maintaining high light transmission through the metasurface to the conversion elements.
3Measurement precision
If traditional optical filtering is used to obtain color information, then color accuracy is improved, but light transmittance deteriorates due to filtering losses
Solution Approach 1:
The patent replaces the traditional mechanical/optical filtering system with a metasurface-based wavefront modulation system. Instead of using absorptive or reflective color filters that block light, the metasurface uses subwavelength microstructures to manipulate light propagation directions based on frequency, achieving color separation through constructive interference and directional transmission rather than filtering.
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 approach enhances light transmittance across spectral channels, increases overall light utilization, and improves imaging quality by reducing color information loss and enhancing color fidelity.
Implementation Method 1
The microstructure and the first substrate are configured to generate a spatial transmission phase in a tangential direction of the array of metasurface structures, to obtain a spatial transmission phase gradient. The spatial transmission phase gradient is used to transmit the optical signal at each frequency band to the optical-to-electrical conversion element corresponding to each frequency band.
Implementation Method 2
The microstructure and the first substrate are configured to transmit an optical signal at each frequency band to an optical-to-electrical conversion element corresponding to each frequency band
Implementation Method 3
The image sensor is configured to convert an optical signal of an image into an analog electrical signal
Data Source
AI summary
An image sensor includes an array of metasurface structures and an array of optical-to-electrical conversion units. The array of metasurface structures is located above the array of optical-to-electrical conversion units. A first optical-to-electrical conversion unit in the array of optical-to-electrical conversion units includes a plurality of optical-to-electrical conversion elements, each optical-to-electrical conversion element in the first optical-to-electrical conversion unit corresponds to one frequency band in a spectrum. A first metasurface structure in the array of metasurface structures includes a first substrate and a microstructure located above the first substrate. The first substrate and the microstructure are configured to transmit an optical signal at each frequency band to an optical-to-electrical conversion element corresponding to each frequency band. The microstructure is a rotationally symmetric structure, and a rotation angle of the rotationally symmetric structure is less than or equal to 90 degrees.