Waveguide Thickness Variation Using a Local Index-Matched Layer

Solution Overview

Problem

Existing augmented reality technologies face challenges in forming substrates with a thickness distribution at eyepiece areas, which affect the performance and design constraints of wearable display devices.

Innovation Solution

A waveguide substrate with a thickness distribution is formed by depositing an index-matched layer on the waveguide substrate, where the device slope of the index-matched layer matches the waveguide slope to achieve a uniform thickness distribution across the eyepiece areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a uniform thickness substrate is used for waveguide, then manufacturing is simpler, but optical performance at eyepiece areas deteriorates due to inability to control thickness distribution

Engineering Contradiction:

Improvethickness distribution controlVSAvoidsubstrate structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a waveguide substrate with non-uniform thickness distribution, where the thickness is specifically controlled to be greater than a first threshold value in eyepiece areas and less than a second threshold value in non-eyepiece areas. This localized thickness variation optimizes optical performance in critical regions while maintaining overall substrate functionality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by varying the thickness parameter of the waveguide substrate across different regions. The thickness is changed from a uniform value to a distributed value system where eyepiece areas have thickness greater than a first threshold and non-eyepiece areas have thickness less than a second threshold, thereby optimizing both optical performance and manufacturing characteristics.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If thickness variation is introduced in eyepiece areas, then optical performance improves, but manufacturing precision requirements worsen

Engineering Contradiction:

Improveoptical performanceVSAvoidthickness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a waveguide substrate with non-uniform thickness distribution, where the thickness is specifically controlled to be greater than a first threshold value in eyepiece areas and less than a second threshold value in non-eyepiece areas. This localized thickness variation optimizes optical performance in critical regions while maintaining overall substrate functionality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by varying the thickness parameter of the waveguide substrate across different regions. The thickness is changed from a uniform value to a distributed value system where eyepiece areas have thickness greater than a first threshold and non-eyepiece areas have thickness less than a second threshold, thereby optimizing both optical performance and manufacturing characteristics.

Inventive Principle:

Principle #35Parameter changes

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 enhances the performance of the substrate by ensuring a consistent thickness distribution, improving the functionality and design of augmented reality devices.

Implementation Method 1

depositing an index-matched layer onto a surface of the waveguide

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS20260079296A1Total or local thickness variation for optical devices

Publication Date: 2026.03.19 APPLIED MATERIALS INC

AI summary

Embodiments of the present disclosure generally relate to methods for forming a waveguide. Methods may include measuring a waveguide substrate, the waveguide having a substrate thickness distribution; and depositing an index-matched layer onto a surface of the waveguide, the index-matched layer having a first surface disposed on the waveguide substrate and a second surface opposing the first surface, wherein the index-matched layer is disposed only over a portion of the waveguide substrate, and a device slope of a second surface of the index-matched layer is substantially the same as the waveguide slope of the first surface of the waveguide.