Double-Helix Light-Guide Expansion for Compact Wide-FoV Displays

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Solution Overview

Problem

Wearable optical devices, such as near eye displays or smart glasses, are cumbersome, have limited field-of-view (FoV), and require heavy and expensive solutions to increase FoV, which affects comfort and safety.

Innovation Solution

A wearable optical device with a system of stacked waveguides and aperture expanders that utilize total internal reflection and diffraction gratings to expand image beams in multiple dimensions, allowing for a wider FoV and improved image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If total internal reflection is used in a light-guide to transmit images, then the device can be made compact, but the field-of-view width is limited

Engineering Contradiction:

Improvedevice compactnessVSAvoidfield-of-view width

Core Design Contradiction:

Volume of moving objectVSArea of stationary object

Solution Approach 1:

The patent transitions from single-dimension light guidance to multi-dimensional beam expansion by introducing a second waveguide that expands beams in a direction perpendicular to the first waveguide's propagation axis. This dimensional expansion allows the system to achieve wider field-of-view without increasing the longitudinal compactness of the device.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The optical system is divided into multiple waveguides (first waveguide for initial guidance, second waveguide for lateral expansion, third waveguide for final output). Each waveguide handles a specific portion of the beam expansion process, allowing the system to achieve wide FoV while maintaining compactness through functional segmentation.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If low-refractive index light-guide materials are used, then the device is easier to manufacture, but the angular range transmitted is reduced

Engineering Contradiction:

Improvematerial availabilityVSAvoidangular range transmitted

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces reliance on high-refractive-index materials with a geometric optical system using multiple waveguides and beam expansion elements. This substitution allows the system to achieve wide angular range without requiring specialized high-index materials, thereby maintaining ease of manufacture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If geometric boundaries are increased to expand field-of-view, then the field-of-view width increases, but the device becomes heavy and expensive

Engineering Contradiction:

Improvefield-of-view widthVSAvoiddevice weight

Core Design Contradiction:

Area of stationary objectVSWeight of moving object

Solution Approach 1:

The patent uses thin-film waveguide structures and substrate-mounted optical elements to achieve beam expansion. This approach replaces heavy geometric boundary solutions with lightweight thin-film technologies, maintaining compactness and reducing weight while achieving the desired field-of-view expansion.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution provides a wider field-of-view and enhanced image quality while maintaining a compact form factor, improving user comfort and safety.

Implementation Method 1

the first waveguide may be configured to receive the second portion of guided image beams and provide a transmitted second portion of guided image beams

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

A wearable optical device with a system of stacked waveguides and aperture expanders that utilize total internal reflection and diffraction gratings to expand image beams in multiple dimensions

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS12399371B1Double-helix onto a single light-guide optical element (LOE)

Publication Date: 2025.08.26 LUMUS LTD

AI summary

An optical device may include a first waveguide to receive and expand in a first dimension a first portion of guided image beams based on a first image field and provide a first plurality of expanded image beams; a second waveguide to receive and expand in the first dimension one of a second portion of guided image beams and a transmitted second portion of guided image beams corresponding to a second image field that is different from the first image field and to provide a second plurality of expanded image beams, the second waveguide to receive the first plurality of expanded image beams and provide a transmitted first plurality of expanded image beams; and a third waveguide to receive and expand in a second dimension the transmitted first plurality of expanded image beams and the second plurality of expanded image beams to provide a third plurality of expanded image beams.