Overlapping Metalens Array for Uniform AR Display Illumination
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Solution Overview
Problem
Conventional glass or polymer micro-lens arrays in AR head-mounted displays are bulky, heavy, suffer from chromatic and spherical aberrations, and have pixelation issues due to imperfections at the lens edges, hindering real-time applications.
Innovation Solution
Employing an overlapping metalens array with nanostructures made of dielectric or metal materials, arranged in an overlapping configuration to mitigate pixelation and improve image quality, utilizing phase-changing materials for focus adjustability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional glass or polymer micro-lens arrays are used, then the optical system can focus light, but the device becomes bulky and heavy
Solution Approach 1:
The patent replaces conventional glass or polymer micro-lens arrays with a metalens array fabricated using CMOS-compatible nanofabrication techniques. The metalens uses sub-wavelength nanostructures (meta-atoms) to manipulate light through geometric phase control rather than traditional refraction, eliminating the need for bulky glass lenses and reducing the optical system to a thin, lightweight planar structure.
Solution Approach 2:
The metalens array is implemented as a thin planar film with sub-wavelength thickness, replacing the thick curved surfaces of conventional lenses. This thin-film approach allows the optical system to be integrated into head-mounted displays with minimal form factor, achieving both weight reduction and compactness.
2Reliability
If conventional micro-lens arrays are used, then light can be focused, but chromatic and spherical aberrations occur
Solution Approach 1:
The patent changes the fundamental operating parameter of lens design from wavelength-dependent refraction (conventional lenses) to geometric phase control through sub-wavelength nanostructure orientation. This parameter change enables achromatic operation because the geometric phase shift is wavelength-independent, eliminating chromatic aberration. The overlapping configuration further corrects spherical aberration by ensuring all rays converge uniformly.
Solution Approach 2:
The metalens array employs composite nanostructures combining dielectric materials with specific refractive indices, arranged in overlapping patterns. This composite approach allows simultaneous correction of multiple aberration types through the synergistic effect of material properties and geometric configuration, achieving high image quality without conventional aberrations.
3Manufacturing precision
If conventional micro-lens arrays are used, then the optical system can function, but pixelation issues occur due to lens edge imperfections
Solution Approach 1:
The patent merges adjacent metalenses into an overlapping configuration where the active areas of neighboring lenses overlap by a designed factor. This merging eliminates the discrete boundaries between individual lenses, removing the source of pixelation artifacts at lens edges while maintaining the focusing capability across the entire array.
Solution Approach 2:
The overlapping metalens array creates a homogeneous illumination profile across the entire optical aperture by ensuring uniform overlap between adjacent elements. This homogeneity eliminates the non-uniform edge effects and pixelation that plague conventional discrete lens arrays, producing smooth, artifact-free images.
4Speed
If a single metalens is used with high numerical aperture, then focusing capability improves, but the focal length becomes impractically short
Solution Approach 1:
The patent segments a single high-NA metalens into an array of multiple smaller metalenses arranged in a specific pattern. Each individual metalens in the array has a practical focal length, but their collective arrangement achieves the equivalent optical power of a high-NA system. This segmentation allows independent optimization of each element's focal length while achieving the desired overall focusing performance.
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 overlapping metalens array provides uniform illumination, reduces pixelation, and results in a thinner, lighter system with improved image quality and real-time capabilities.
Implementation Method 1
Metalenses enable a facile approach to manipulate the light properties
Data Source
AI summary
A metalens array and a display device are provided, the metalens array includes at least one optical transparent substrate; and a plurality of nanostructures arranged on the at least one optical transparent substrate, the plurality of nanostructures arranged in a predetermined shape to define a plurality of metalenses, and the plurality of metalenses arranged in an overlapping configuration.