Waveguide Cross-Coupling Suppressors for Mixed Environment Displays

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Solution Overview

Problem

Existing near-to-eye display devices, such as head-mounted displays, face challenges in maintaining sharpness of displayed images due to cross-coupling between waveguides, which leads to a drop in modulation transfer function (MTF) values, especially caused by wide grating diffraction efficiency spectra and substrate wedge angle variations.

Innovation Solution

The implementation of stacked structures between waveguides to suppress specific wavelength ranges, using materials like synthetic dyes or organic dyes in pigmentation layers, and retardation films to convert polarization states, thereby reducing cross-coupling and enhancing image sharpness by filtering out unwanted light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If waveguides are stacked to provide multi-color display, then display functionality is improved, but cross-coupling between waveguides increases causing MTF degradation

Engineering Contradiction:

Improvedisplay functionalityVSAvoidMTF value

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A stacked structure comprising multiple layers is introduced as an intermediary element between adjacent waveguides. This stacked structure includes a first layer and a second layer with different optical properties, acting as a mediator to suppress cross-coupling of light between waveguides while allowing the waveguides to maintain their display functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The stacked structure utilizes composite material construction with multiple layers having different optical characteristics. The first layer and second layer are composed of materials with distinct optical properties that work together to suppress cross-coupling across different wavelength ranges, improving overall system reliability without sacrificing functionality.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If grating diffraction efficiency spectra are widened to improve light coupling, then light coupling efficiency is improved, but cross-coupling between adjacent waveguides increases

Engineering Contradiction:

Improvelight coupling efficiencyVSAvoidcross-coupling

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The stacked structure extracts and suppresses the harmful cross-coupled light components that result from wide grating diffraction efficiency spectra. By removing these unwanted optical interactions between adjacent waveguides, the system can maintain high light coupling efficiency while eliminating the associated cross-coupling problems.

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If substrate wedge angle variations are reduced to improve manufacturing precision, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvesubstrate wedge angle precisionVSAvoidsubstrate fabrication complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Rather than attempting to eliminate substrate wedge angle variations through complex fabrication processes, the stacked structure is designed to tolerate and compensate for these variations. The multiple-layer configuration with different optical properties converts the potential harm of wedge angle variations into a manageable parameter, maintaining manufacturing simplicity while achieving the desired optical performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 improves the modulation transfer function (MTF) values by minimizing light coupling between waveguides, resulting in sharper and more focused mixed environment displays with enhanced image quality.

Implementation Method 1

stacked structures for suppressing a predetermined wavelength range corresponding to a wavelength range emitted from a waveguide

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

retardation films to convert polarization states

Methodology Applied

Scientific EffectPolarisation: Polarisation

Implementation Method 3

waveguides, e.g., color plates, that are individually formed to couple a corresponding color output of a micro-display engine and project an image into a human vision system

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS9720237B1Mixed environment display device and waveguide cross-coupling suppressors

Publication Date: 2017.08.01 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

An optical device comprises a number of waveguides, e.g., color plates, that are individually formed to couple a corresponding color output of a micro-display engine and project an image into a human vision system. Some configurations include stacked structures for suppressing a predetermined wavelength range a corresponding to a wavelength range emitted from a waveguide. Techniques, devices, and systems disclosed herein can mitigate cross coupling that occurs between the waveguides to provide enhanced MTF values over devices that do not include the stacked structures. Individual optical devices configured to suppress a predetermined wavelength range are also provided.