Wavelength-Specific Diffraction in Light Guides for Uniform AR Efficiency
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Solution Overview
Problem
Existing augmented reality devices suffer from non-uniform diffraction efficiency of light across different wavelengths and angles, leading to reduced optical performance.
Innovation Solution
A light guide member comprising multiple light guides with wavelength-specific diffraction patterns, each guide having structures that react to specific wavelength ranges, allowing for uniform and high diffraction efficiency across a wide incident angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single diffraction pattern is used in the waveguide, then the device structure is simple, but the diffraction efficiency is not uniform across different wavelengths and angles
Solution Approach 1:
The waveguide is divided into multiple light guide regions (first, second, and third light guides), each containing diffraction patterns optimized for specific wavelength ranges. This segmentation allows each region to specialize in diffracting particular wavelengths, achieving uniform diffraction efficiency across the entire visible spectrum while maintaining a relatively simple overall structure.
Solution Approach 2:
Different regions of the waveguide are assigned different diffraction pattern characteristics tailored to their functional requirements. The first light guide handles 380-500nm wavelengths, the second handles other wavelength ranges, and the third provides additional spectral coverage. This local optimization ensures that each region contributes maximally to the overall diffraction efficiency uniformity.
2Reliability
If the diffraction pattern is optimized for a narrow wavelength range, then the diffraction efficiency is high for that specific range, but the bandwidth is limited
Solution Approach 1:
The waveguide is designed to perform multiple functions by incorporating three distinct light guides, each responsible for diffracting different wavelength ranges. This multi-functional design enables the single waveguide device to handle the entire visible spectrum effectively, achieving both high diffraction efficiency for each wavelength range and broad overall bandwidth coverage.
3Reliability
If the diffraction pattern is optimized for normal incidence, then the diffraction efficiency is high at normal angles, but the efficiency drops at wide incident angles
Solution Approach 1:
The diffraction patterns in each light guide region are designed with specific geometric parameters optimized for their respective wavelength ranges and incident angle conditions. By carefully controlling parameters such as pattern size, spacing, and shape in each region, the system achieves uniform diffraction efficiency across both wavelength and incident angle variations.
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 ensures uniform and high diffraction efficiency for different wavelengths, improving visibility and optical performance in augmented reality devices by optimizing diffraction efficiency across a wide range of angles.
Implementation Method 1
Light emitted from the projector is diffracted by the waveguide or AR glasses. Then, the diffracted light may enter the eyes of a user. Therefore, the waveguide or the AR glasses may include a diffraction pattern.
Data Source
AI summary
A light guide member according to an embodiment comprises at least one light guide from among a first light guide, a second light guide and a third light guide, wherein each of the first light guide, the second light guide and the third light guide includes a structure that reacts to light of different wavelength ranges, the first light guide includes a first substrate and a first structure, which is arranged on the first substrate and reacts to light of a first wavelength range, the first wavelength is 380 nm to 500 nm, the first structure is formed from an aggregate of a plurality of first unit structures, the structure of the first unit structures includes a first protrusion, the first protrusion protrudes in a first direction, and the first protrusion is symmetrical with respect to a second direction by having, as the axis thereof, the first direction line, which passes through the center of the first unit structure.