AR Stray Light Reduction via Anti-Reflection Coatings and Shields
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Solution Overview
Problem
Augmented reality systems face significant challenges in managing stray light, which leads to glare, ghost images, and reduced contrast due to light intermixing between real world and display light channels, and existing solutions like anti-reflection coatings are insufficient for these systems.
Innovation Solution
The implementation of anti-reflection coatings on coverwindows and MLA substrates, combined with opto-mechanical shields and high transparency materials, along with larger lenslet designs and annular shields to separate and block stray light, effectively reducing unwanted stray light and improving light throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-reflection coatings are applied to reduce stray light, then stray light reduction is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies multi-layer anti-reflection coatings composed of different materials with varying refractive indices on the coverwindow and MLA substrate surfaces. These composite coating structures reduce stray light through optimized optical interference while maintaining manufacturability through established coating processes.
Solution Approach 2:
The patent optimizes the thickness and refractive index parameters of anti-reflection coating layers to minimize stray light across specific wavelength ranges. By carefully controlling these parameters, the system achieves reduced stray light while using standard coating technologies.
2Object-affected harmful factors
If opto-mechanical shields and annular shields are added to block stray light, then stray light reduction is improved, but device complexity increases
Solution Approach 1:
The patent divides the light blocking function into multiple segmented shields: opto-mechanical shields positioned at specific locations and annular shields surrounding individual lenslets. This segmentation allows targeted stray light reduction while maintaining overall system transparency and managing structural complexity through modular design.
Solution Approach 2:
The patent applies different shielding structures at different locations based on local stray light problems. Annular shields are placed around lenslets where lateral stray light occurs, while opto-mechanical shields are positioned where vertical stray light paths exist, creating locally optimized solutions throughout the system.
3Loss of energy
If larger lenslet designs are used to improve light throughput, then light throughput is improved, but stray light increases
Solution Approach 1:
The patent uses annular shields as thin film-like structures surrounding lenslets that block lateral stray light while allowing the lenslet itself to maintain its larger size for improved light throughput. The annular shields act as selective barriers that do not interfere with the primary light function.
Solution Approach 2:
The patent introduces opto-mechanical shields as intermediary structures between the display and the environment, and annular shields as intermediaries around lenslets. These intermediary elements block stray light paths without interfering with the intended light throughput through the optical system.
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
This approach significantly reduces stray light and light loss, enhancing the overall image quality by minimizing ghost images and glare, while maintaining optimal throughput of intended light in augmented reality systems.
Implementation Method 1
The implementation of anti-reflection coatings on coverwindows and MLA substrates
Implementation Method 2
opto-mechanical shields and high transparency materials, along with larger lenslet designs and annular shields to separate and block stray light
Implementation Method 3
The display emitted light follows a path from the display element, through the lenslet in the MLA, enters the eye's lens and is focused by the eye lens onto the retina
Implementation Method 4
high transparency materials, along with larger lenslet designs and annular shields to separate and block stray light, effectively reducing unwanted stray light and improving light throughput
Data Source
AI summary
Systems and apparatus for managing stray light in augmented reality, mixed reality, enhanced reality, and similar applications.