Color-Selective Waveguides for AR Stray Light Reduction
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Solution Overview
Problem
Current augmented reality (AR)/mixed reality (MR) eyepiece stacks face issues with stray light due to the close proximity of color-specific waveguides, leading to ghost images and reduced optical contrast, as stray light from one color can propagate into neighboring waveguides.
Innovation Solution
The development of color-selective waveguides, where a polymer waveguide is formed by dispensing and polymerizing materials with chromatic components to selectively absorb specific wavelengths of light, such as red, green, or blue, thereby reducing or blocking stray light and minimizing back-reflection or back-scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If color-specific waveguides are placed in close proximity to each other, then the device compactness is improved, but stray light from one color propagates into neighboring waveguides causing ghost images and reduced contrast
Solution Approach 1:
A dichroic filter layer is introduced as an intermediary between adjacent color waveguides. This filter layer selectively transmits specific wavelengths while blocking others, acting as a mediator that prevents stray light from one color waveguide from interfering with neighboring waveguides, thus maintaining compact arrangement without sacrificing optical contrast
Solution Approach 2:
Dichroic filter layers with specific spectral transmission characteristics are applied to different waveguide layers. These filters are designed to transmit the intended color wavelength range while blocking other wavelengths, enabling color-selective light propagation and preventing cross-contamination between color channels in the compact stacked configuration
2Adaptability or versatility
If separate R, G, B waveguide layers are stacked together, then color-specific light guidance is achieved, but manufacturing complexity increases due to precise alignment requirements
Solution Approach 1:
Multiple waveguide layers with different color specifications are combined into a single integrated optical device. The waveguides are stacked and bonded together with precise alignment, allowing each layer to guide its specific color wavelength while forming a unified compact structure that achieves color-specific light guidance without requiring separate manufacturing processes
Solution Approach 2:
The optical device is segmented into distinct color-specific waveguide layers (R, G, B), each responsible for guiding a specific wavelength range. This segmentation allows independent optimization of each layer's optical properties while the overall stacked structure provides the complete color guidance functionality, with dichroic filters providing additional spectral separation
3Area of stationary object
If incoupling gratings are positioned in close proximity in the super-pupil, then the pupil area utilization is improved, but stray light from diffraction at the LCOS enters neighboring ICGs reducing optical contrast
Solution Approach 1:
Dichroic filter layers are positioned between incoupling gratings for different colors, acting as intermediaries that block diffracted stray light from one color from reaching neighboring incoupling gratings. This allows the incoupling gratings to be positioned in close proximity for efficient pupil area utilization while maintaining high optical contrast by filtering out unwanted diffracted wavelengths
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 implementation of color-selective waveguides effectively reduces stray light entry into the waveguide, enhancing optical properties like contrast by allowing only the desired wavelength to pass through while absorbing the rest, thus improving the overall performance of AR/MR eyepieces.
Implementation Method 1
a polymer waveguide is formed by dispensing and polymerizing materials with chromatic components to selectively absorb specific wavelengths of light, such as red, green, or blue, thereby reducing or blocking stray light
Implementation Method 2
polymerizing the first polymerizable material and the second polymerizable material to yield a patterned polymer layer between the first mold and the second mold
Data Source
AI summary
Color-selective waveguides, methods for fabricating color-selective waveguides, and augmented reality (AR)/mixed reality (MR) applications including color-selective waveguides are described. The color-selective waveguides can advantageously reduce or block stray light entering a waveguide (e.g., red, green, or blue waveguide), thereby reducing or eliminating back-reflection or back-scattering into the eyepiece.