Optical Waveguide Detection Element for Compact XR Alignment

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Solution Overview

Problem

Existing XR glasses, such as AR and VR glasses, have not been miniaturized due to separate video light source and eye tracking modules, complicating optical axis alignment.

Innovation Solution

An optical waveguide detection element integrating a video light source module and an eye tracking module, utilizing a substrate with optical waveguides for visible and near-infrared light, and a photodetector for light reception, with ports arranged on one end surface for miniaturization and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the video light source module and eye tracking module are separate, then each module can be optimized independently, but the overall device size increases and optical axis alignment becomes complicated

Engineering Contradiction:

Improveoptical axis alignmentVSAvoiddevice size

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent combines the video light source module and eye tracking module into a single integrated optical waveguide detection element. The visible light waveguide and near-infrared light waveguide are merged within the same optical waveguide layer, sharing common structural components and mounting surfaces. This integration eliminates the need for separate module assemblies, directly reducing device volume while simplifying optical axis alignment since both light sources and their corresponding waveguides are fabricated and positioned as a unified structure.

Inventive Principle:

Principle #5Merging (Combining)

2Volume of moving object

If the video light source module and eye tracking module are integrated, then device size is reduced and optical axis alignment is simplified, but the structural complexity of the waveguide layer increases

Engineering Contradiction:

Improvedevice sizeVSAvoidwaveguide layer structure

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The optical waveguide layer is designed as a multi-functional universal structure that simultaneously supports both visible light transmission for video display and near-infrared light transmission for eye tracking. The waveguide layer includes multiple waveguide regions with different refractive indices, but they all share the same base structure, substrate interface, and output coupling mechanism. This universal design allows the system to perform multiple functions through a single integrated structure, managing complexity through functional consolidation rather than separate specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies local quality by creating spatially varying refractive index regions within the optical waveguide layer. Different portions of the waveguide layer have locally optimized properties: the first waveguide region has refractive index characteristics optimized for visible light, while the second waveguide region has characteristics optimized for near-infrared light. This local differentiation allows each functional region to be optimized for its specific purpose while maintaining overall structural integration, managing complexity through localized optimization rather than global redesign.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If separate modules are used, then module optimization is easier, but the number of components and assembly steps increases

Engineering Contradiction:

Improvemodule optimizationVSAvoidassembly efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent merges the video light source and eye tracking module into a single integrated unit where both light sources are mounted on the same substrate, both waveguides are formed in the same waveguide layer, and both output ports are positioned on the same surface. This consolidation eliminates multiple assembly steps including separate module mounting, alignment, and coupling operations. The integrated structure is fabricated as a unified component, directly improving productivity by reducing assembly complexity and manufacturing steps while maintaining the ability to optimize each functional region during the fabrication process.

Inventive Principle:

Principle #5Merging (Combining)

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

Enables miniaturization and simplifies optical axis alignment by integrating the video light source and eye tracking modules, facilitating the development of compact XR glasses.

Implementation Method 1

an optical waveguide layer (20) formed on the substrate (10)

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a photodetector (30)

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS20260010009A1Optical waveguide detection element, video laser module, and XR glasses

Publication Date: 2026.01.08 TDK CORP

AI summary

A video laser module includes: a substrate; an optical waveguide layer formed on the substrate; a visible laser light source configured to output visible light; and an electrical signal generation element. The optical waveguide layer includes: a first optical waveguide in which the visible light having a wavelength of 380 nm to 800 nm propagates; and a visible light output port of the first optical waveguide from which the visible light is output. The electrical signal generation element generates an electrical signal for controlling a drive current of the visible laser light source.