AR Optical Stack Refractive Index Optimization
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Solution Overview
Problem
Augmented reality devices face challenges in achieving improved transmission, field of view, reduced weight, and color balance while maintaining effective image propagation and wearability.
Innovation Solution
A device comprising a stack of optical elements with specific refractive indices and spacer regions made of materials with refractive indices below 1.4, arranged to optimize transmission and color balance, and potentially coated for antireflective properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If optical elements with high refractive index are used to improve transmission and field of view, then optical performance is improved, but weight increases
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the refractive index values of optical elements (specifically n-doped silica layers with refractive indices between 1.44-1.48) and spacer thicknesses (5-50 nm) to achieve high transmission while controlling weight. The incremental doping approach allows fine-tuning of optical properties without proportionally increasing material density.
Solution Approach 2:
The patent uses composite materials by combining multiple layers of silica with different nitrogen doping concentrations to create a multi-layer optical element. This composite structure with alternating high and low refractive index layers enhances transmission through constructive interference while maintaining reasonable weight by using lightweight silica-based materials rather than heavier alternatives.
2Illumination intensity
If multiple optical elements are stacked to improve transmission and color balance, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the optical system into multiple discrete layers within each optical element, where each layer has a specific nitrogen doping concentration and thickness. This segmentation allows independent optimization of each layer's optical properties to achieve overall high transmission and color balance while maintaining manufacturability through standardized layer structures.
Solution Approach 2:
The patent achieves multi-functionality by designing optical elements that simultaneously perform multiple functions: wavelength-selective transmission, color balancing, and field of view control all within the same stacked configuration. The universal silica-based platform with variable nitrogen doping can be tuned to address multiple optical requirements without requiring different material systems.
3Illumination intensity
If spacer regions with low refractive index are used to improve color balance, then color performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses parameter changes by systematically varying the spacer thickness (5-50 nm) and nitrogen doping concentration in adjacent layers to optimize color balance. The low refractive index of the spacers (below 1.4) creates the necessary optical path differences for color correction, and the precise control of these parameters during atomic layer deposition enables achieving target color coordinates.
Solution Approach 2:
The patent directly addresses color balance by engineering the optical interference effects through controlled layer thicknesses and refractive index variations. The alternating high and low refractive index layers create wavelength-dependent transmission characteristics that can be tuned to achieve neutral or desired color points, effectively using optical interference to correct color imbalances.
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 provides a balanced combination of low density and high transmission, enhancing the overall performance of augmented reality devices by improving image quality and user experience.
Implementation Method 1
a spacer region made of a material having a refractive index below 1.4 for vacuum wavelengths in the range from 400 to 760 nm located between each pair of adjacent optical elements
Data Source
AI summary
The present disclosure relates to a device, in particular an augmented reality device. In particular, the disclosure relates to a device, a kit, a process for making the device, and a process for making a visual impression.