Crossed-Grating Waveguide Multiplexer for 2D AR Light Distribution

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Solution Overview

Problem

Existing augmented reality (AR) technologies face challenges in providing a comfortable and natural-feeling presentation of virtual image elements amidst real-world imagery due to the complexity of the human visual system, particularly in simulating realistic depth perception.

Innovation Solution

A two-dimensional waveguide light multiplexer is employed, utilizing crossed diffraction gratings on the top and bottom surfaces of a waveguide, allowing for the distribution and outcoupling of light in two dimensions, which can enhance the presentation of virtual content in AR devices by efficiently directing light signals to other optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional light multiplexing methods are used, then device complexity is reduced, but light distribution precision and depth perception capability deteriorate

Engineering Contradiction:

Improvelight distribution precisionVSAvoidoptical element complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent transitions from traditional one-dimensional light multiplexing to two-dimensional light distribution by arranging diffraction gratings in orthogonal directions (x and y axes). This dimensional expansion enables precise control of light propagation in multiple directions simultaneously, achieving superior light distribution precision and depth perception capability while maintaining manageable device complexity through the waveguide structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If crossed diffraction gratings are used for two-dimensional light distribution, then depth perception and virtual content presentation are improved, but manufacturing complexity increases

Engineering Contradiction:

Improvedepth perception accuracyVSAvoidgrating alignment difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines multiple diffraction gratings (first and second gratings in orthogonal directions) onto a single waveguide structure. This merging approach enables two-dimensional light distribution and improved depth perception while consolidating multiple optical functions into one integrated component, thereby reducing the overall number of separate elements that would need to be assembled and aligned.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The waveguide serves as an intermediary structure that facilitates the integration of crossed diffraction gratings. By providing a common substrate with controlled refractive index, the waveguide enables precise positioning and alignment of the gratings in orthogonal directions, simplifying the manufacturing process compared to assembling separate optical elements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If light is distributed in two dimensions, then virtual content integration with real world is enhanced, but energy loss in the waveguide increases

Engineering Contradiction:

Improvevirtual-real world integrationVSAvoidlight propagation loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent segments the light distribution function into two independent orthogonal components using separate diffraction gratings for x-direction and y-direction control. This segmentation allows each grating to be optimized for its specific direction, improving overall light distribution efficiency and reducing energy loss compared to a single complex two-dimensional grating structure.

Inventive Principle:

Principle #1Segmentation

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 enables a more realistic and comfortable AR experience by effectively distributing light in two dimensions, enhancing the perception of depth and improving the integration of virtual objects with the real world, thus providing a more immersive AR environment.

Implementation Method 1

at least one or more first diffraction gratings having a grating direction, the one or more first diffraction gratings disposed on a major surface of the waveguide, and at least one or more second diffraction gratings having a grating direction

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12504667B2Waveguide light multiplexer using crossed gratings

Publication Date: 2025.12.23 MAGIC LEAP INC

AI summary

A two-dimensional waveguide light multiplexer can efficiently multiplex and distribute a light signal in two dimensions. An example of a two-dimensional waveguide light multiplexer can include a waveguide, a first diffraction grating, and a second diffraction grating arranged such that the grating direction of the first diffraction grating is perpendicular to the grating direction of the second diffraction grating. In some examples, the first and second diffraction gratings are on opposite sides of a waveguide. In some examples, the first and second diffraction gratings are on a same side of a waveguide, with the second grating over the first grating.