Optical Layered Composite With Reduced High-Index Layers for AR Color Fidelity
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Solution Overview
Problem
Augmented reality devices face challenges in achieving good real-world image quality, overlaid image quality, and wearability while minimizing in-plane optical loss and improving color fidelity.
Innovation Solution
An optical layered composite with specific refractive index and thickness ratios in coating layers, including groups A and B, is used to enhance image propagation and reduce reflectivity, weight, and improve optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional coating designs with high refractive index layers are used, then anti-reflect properties are achieved, but in-plane optical loss increases and color fidelity deteriorates
Solution Approach 1:
The patent changes the refractive index parameter distribution in the coating layers, specifically using a gradient approach where the refractive index decreases from the substrate interface toward the outer surface. This parameter optimization reduces in-plane optical loss while preserving color fidelity by carefully selecting refractive indices (e.g., 1.7, 1.5, 1.3) and thicknesses for each layer.
Solution Approach 2:
The patent employs composite coating structures combining multiple materials with different refractive indices (such as TiO2, SiO2, and hybrid organic-inorganic materials) to create a multi-layer system that simultaneously achieves low optical loss and high color fidelity through synergistic material properties.
2Object-affected harmful factors
If conventional anti-reflective coatings are applied, then reflectivity is reduced, but device weight increases
Solution Approach 1:
The patent utilizes thin film technology to create anti-reflective coatings with total thicknesses ranging from 50-200 nanometers. These ultra-thin films provide effective anti-reflective properties while contributing negligibly to device weight, thereby resolving the contradiction between reflectivity reduction and weight minimization.
3Manufacturing precision
If image propagation is improved in transverse direction, then overlaid image quality increases, but real world image quality deteriorates
Solution Approach 1:
The patent applies local quality optimization by designing the coating structure to have directionally selective optical properties. The coating is engineered to provide enhanced guidance and propagation for transverse-traveling overlaid images through specific refractive index gradients, while simultaneously maintaining high transmission and quality for longitudinally incident real-world light through optimized layer configurations.
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 optical layered composite improves image propagation, reduces in-plane optical loss, enhances color fidelity, and provides good anti-reflective properties, resulting in a lightweight and high-quality augmented reality device.
Implementation Method 1
a coating comprising a group A of coating layers having a refractive index of 1.7 or more and a group B of coating layers having a refractive index of less than 1.7
Implementation Method 2
improve color fidelity... provide a device in which transverse propagation of an image is improved whilst simultaneously achieving good anti-reflect properties
Data Source
AI summary
An optical layered composite includes: a substrate having a front face, a back face, a thickness ds between the front face and the back face and a refractive index ns; and a coating applied to the front face. The coating comprises a group A of coating layers having a refractive index of 1.7 or more and a group B of coating layers having a refractive index of less than 1.7. The sum of the thicknesses of the layers of the group A is at most 55% of the total thickness dc of the coating.