Near-Eye Display Waveguide Encapsulation Against Dust and Moisture
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Solution Overview
Problem
Optical waveguides in near-eye display systems are susceptible to environmental contamination from water vapor and dust particles, leading to optical distortion due to changes in ambient pressure and temperature, affecting image quality.
Innovation Solution
An encapsulated waveguide system with first and second outer layers enclosing the waveguide substrate, sealed by a spacer and sealing element, forming cavities filled with inert gas or dry air to maintain pressure equilibrium and protect against environmental contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the waveguide substrate is exposed to the ambient environment, then the device structure remains simple and accessible, but the optical performance deteriorates due to contamination from water vapor and dust particles
Solution Approach 1:
The patent applies the inert atmosphere principle by encapsulating the waveguide substrate within a sealed housing that maintains a controlled internal environment. The housing prevents ambient water vapor and dust particles from contacting the waveguide substrate, effectively creating a protected atmosphere that preserves optical performance without requiring complex active protection systems
Solution Approach 2:
The patent employs thin film encapsulation layers on the waveguide substrate surfaces. These thin protective films act as barriers against environmental contaminants while maintaining optical transparency, allowing the waveguide to remain accessible yet protected from harmful atmospheric elements
2Stability of the object's composition
If the waveguide substrate is directly exposed to ambient air, then the manufacturing and assembly process remains simple, but the optical behavior becomes unstable due to pressure and temperature fluctuations
Solution Approach 1:
The sealed housing creates a stable, isolated environment for the waveguide substrate, shielding it from ambient pressure and temperature fluctuations. This encapsulation approach maintains consistent optical behavior while using a relatively simple sealed structure that does not complicate the manufacturing process significantly
Solution Approach 2:
The patent divides the device into separate enclosed compartments within the housing structure. By segmenting the internal space and creating distinct sealed chambers around the waveguide substrate, the design isolates the optical components from environmental variations while maintaining a modular assembly process
3Object-affected harmful factors
If the waveguide substrate is enclosed in a sealed housing, then protection against environmental contaminants is achieved, but the device structure becomes more complex
Solution Approach 1:
The patent implements protection against environmental contamination through a sealed housing that creates an isolated internal environment. The housing structure, while adding some complexity, provides comprehensive protection by preventing water vapor and dust particles from reaching the waveguide substrate, ensuring long-term reliability
Solution Approach 2:
The sealed housing structure serves multiple functions simultaneously: it protects against environmental contaminants, maintains stable pressure and temperature conditions, and provides structural support for the waveguide substrate. This multi-functionality reduces the need for additional separate protection components, thereby limiting the increase in device complexity
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 encapsulated waveguide system maintains optical performance by isolating the waveguide from ambient pressure and temperature fluctuations, preventing distortion and ensuring clear image projection.
Implementation Method 1
The projector light is coupled in by the input area into the transparent waveguide substrate, then propagates along said substrate via total internal reflection until being coupled out from said substrate by the output area towards the user's eye
Implementation Method 2
The input area and the output area are typically made of a refractive index matched spin coated polymer layer on the transparent waveguide substrate surface that may be embossed by a master mold and cured by UV light (nano-imprinting), or exposed to UV through a mask and etched via a chemical process that discriminates between exposed and unexposed areas (nano-lithography), so as to form nanometer-sized patterns able to diffract light in a controlled manner
Data Source
AI summary
An encapsulated waveguide system for a near eye optical display includes a first outer layer, a second outer layer, at least one waveguide substrate comprising an input area and an output area, a first spacer and a sealing element. The at least one waveguide substrate is disposed between the first and second outer layers and spaced therefrom by the first spacer. The sealing element joins edges of the first and second outer layers so as to encapsulate the at least one waveguide substrate within a cavity formed by the first and second outer layers. The formed cavity includes a first cavity between the at least one waveguide substrate and the first outer layer and a second cavity between the at least one waveguide substrate and the second outer layer.