Waveguide Flexure Alignment for HMD Optical Stability

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Solution Overview

Problem

Existing head-mounted displays face challenges in maintaining optimal optical alignment between waveguides and projectors, leading to deviations in optical quality that affect user experience, and lack effective protection against physical jarring.

Innovation Solution

The use of flexure elements to independently align and secure waveguides relative to the frame and projectors, allowing for precise optical alignment and protection against physical shocks by applying an inward biasing force, while also utilizing fiducial marks and cameras for accurate positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If waveguides are rigidly mounted to the frame, then structural stability is improved, but optical alignment precision deteriorates due to inability to compensate for manufacturing tolerances and physical jarring

Engineering Contradiction:

Improvestructural stabilityVSAvoidoptical alignment precision

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs flexure elements (thin flexible mechanical structures) to mount the waveguide to the frame. These flexure elements provide a compliant connection that allows precise optical alignment while maintaining structural stability. The flexibility enables compensation for manufacturing tolerances and physical shocks without compromising the overall structural integrity of the head-mounted display.

Inventive Principle:

Principle #30Flexible shells and thin films

2Manufacturing precision

If waveguides are independently aligned relative to projectors, then optical quality is improved, but device complexity increases due to additional alignment mechanisms

Engineering Contradiction:

Improveoptical qualityVSAvoidalignment mechanism complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The flexure elements serve as simple yet effective compliant mounts that enable independent alignment of the waveguide relative to the projector. Rather than complex active alignment mechanisms, the patent uses passive flexible mechanical structures that allow precise positioning while keeping the overall device complexity low. The independent alignment is achieved through the natural compliance of the flexure elements during assembly.

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

This solution enhances the optical alignment of waveguides and projectors, reducing optical deviations and protecting the waveguides from physical damage, thereby improving user experience and display quality.

Implementation Method 1

each of the at least two flexure elements applying a holding force against a peripheral edge of the waveguide

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20230314806A1Systems and methods for alignment of optical components

Publication Date: 2023.10.05 META PLATFORMS TECHNOLOGIES LLC

AI summary

Head-mounted displays may include a frame, a light projector coupled to the frame, a waveguide configured to direct images from the light projector to a user’s eye, and at least one flexure element coupled to the frame and physically supporting the waveguide in the frame. Various other methods, systems, and devices are also disclosed.