Liquid Crystal Polarization Holograms and Metasurfaces for Image Sensor Bulk Reduction
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Solution Overview
Problem
Conventional image sensors use bulkier optical components like polarizers, wavelength filters, and refractive microlenses, which can cause resolution issues and reduce the signal-to-noise ratio (SNR).
Innovation Solution
The use of liquid crystal polarization holograms (LCPH) and metasurfaces, configured with the functionality of polarizers, wavelength filters, and microlenses, to replace conventional optical components in imaging systems, thereby focusing image light onto subpixels of an image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional optical components (polarizers, wavelength filters, refractive microlenses) are used in image sensors, then the sensors can perform basic imaging functions, but the sensors become bulkier and resolution deteriorates
Solution Approach 1:
The patent combines multiple optical functions (polarization filtering, wavelength filtering, and light focusing) into a single integrated metasurface layer. This metasurface simultaneously performs the functions of conventional polarizers, wavelength filters, and microlenses, eliminating the need for separate bulkier components and thereby reducing overall sensor volume while maintaining or improving resolution
Solution Approach 2:
The patent replaces conventional refractive microlenses with metasurfaces that use subwavelength optical structures to achieve light focusing. This substitution eliminates the need for thick refractive optical elements and replaces them with thin metasurface layers that can focus light more efficiently, reducing bulk while improving resolution
2Reliability
If conventional optical components are used in image sensors, then the sensors can capture images, but the signal-to-noise ratio is reduced
Solution Approach 1:
The patent merges multiple optical filtering and focusing functions into a single metasurface layer, which improves signal-to-noise ratio by more efficiently directing relevant light signals to appropriate photodetectors while reducing the complexity of assembling and aligning multiple separate optical components
Solution Approach 2:
The metasurface layer is designed to perform multiple functions simultaneously (polarization filtering, wavelength filtering, and focusing), making the optical system more efficient at separating signal from noise while reducing the number of components that could introduce misalignment errors or signal loss
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 reduces the bulk of image sensors, enhances resolution, and improves the signal-to-noise ratio by efficiently focusing image light onto subpixels, allowing for more effective sensing of various wavelengths of light.
Implementation Method 1
refractive microlenses are used to focus image light to a sensor
Implementation Method 2
diffractive lenses
Implementation Method 3
liquid crystal polarization holograms (LCPH)
Data Source
AI summary
Imaging systems, cameras, and image sensors of this disclosure include imaging pixels that include subpixels. Diffractive optical elements such as a metasurface lens layers or a liquid crystal polarization hologram (LCPH) are configured to focus image light to the subpixels of the imaging pixels. Microlens regions of the diffractive optical elements may focus the image light to the subpixels of the imaging pixels.