Spatially Variable Liquid Crystal Diffraction Gratings for AR Displays
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Solution Overview
Problem
Current augmented reality (AR) and virtual reality (VR) technologies face challenges in providing a comfortable and natural-feeling display of virtual image elements amidst real-world imagery, due to the complexity of human visual perception.
Innovation Solution
The development of a diffraction grating with spatially varying liquid crystal layers, where the liquid crystal molecules are aligned differently in each zone, allowing for varying optical properties associated with light diffraction. This diffraction grating is integrated into a head-mounted display device to project augmented reality image content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform diffraction grating is used in AR displays, then the manufacturing process is simple, but the visual comfort and naturalness of virtual image presentation is poor
Solution Approach 1:
The patent applies local quality by creating spatially variable liquid crystal layers with different molecular orientations in different zones of the diffraction grating. Each zone has tailored optical properties (different refractive indices, thicknesses, or orientations) to optimize diffraction efficiency and image quality for specific viewing angles or wavelengths, thereby improving visual comfort and naturalness while maintaining a relatively simple overall manufacturing process using standard liquid crystal alignment techniques
2Productivity
If spatially variable liquid crystal layers are used to improve optical properties, then the visual presentation quality improves, but the device complexity increases
Solution Approach 1:
The patent implements parameter changes by varying liquid crystal layer properties (molecular orientation angles, layer thicknesses, or refractive indices) across different spatial zones of the diffraction grating. This allows optimization of optical performance for enhanced visual presentation quality while avoiding the need for completely different structural designs, thus managing device complexity through controlled parameter variation rather than fundamental structural redesign
3Reliability
If different liquid crystal layers with different molecular alignments are used, then diffraction efficiency and optical control improve, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing alignment layers with specific orientation patterns before liquid crystal deposition. These alignment layers are designed to guide liquid crystal molecules into the desired spatially variable configurations during the liquid crystal formation process, thereby achieving high diffraction efficiency and precise optical control while reducing the actual manufacturing precision requirements during liquid crystal application
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 solution enhances the ability to display virtual content in AR systems by providing different optical properties for each diffracting zone, improving the comfort and naturalness of the virtual image presentation within the real world environment.
Implementation Method 1
a plurality of different liquid crystal layers corresponding to the different diffracting zones, the different liquid crystal layers having liquid crystal molecules that are aligned differently, such that the different diffracting zones have different optical properties associated with light diffraction
Data Source
AI summary
The present disclosure relates to display systems and, more particularly, to augmented reality display systems including diffraction grating(s), and methods of fabricating same. A diffraction grating includes a plurality of different diffracting zones having a periodically repeating lateral dimension corresponding to a grating period adapted for light diffraction. The diffraction grating additionally includes a plurality of different liquid crystal layers corresponding to the different diffracting zones. The different liquid crystal layers include liquid crystal molecules that are aligned differently, such that the different diffracting zones have different optical properties associated with light diffraction.