Mixed-Reality Display Beam Shaping for Wider Depth of Field

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Solution Overview

Problem

Existing augmented reality systems suffer from vergence-accommodation conflict (VAC), leading to user discomfort such as visual fatigue, headache, and eyestrain due to mismatched visual cues between the distance of virtual objects and the focusing distance required by the user's eyes.

Innovation Solution

Implementing a light modifying device in the optical system to dynamically modify collimated pixel beams by converging or reducing their diameter, thereby disrupting accommodation cues and extending the depth of field beyond the VAC threshold, compatible with existing eyepieces that employ pupil-expansion combiner technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed focal plane optical system is used, then the device complexity is reduced, but the depth of field is limited causing vergence-accommodation conflict

Engineering Contradiction:

Improveoptical system complexityVSAvoiduser comfort

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies dynamics by making the optical system adjustable through a light modifying device that can dynamically change the diameter of collimated pixel beams. This allows the system to adapt between different viewing conditions (near-field and far-field) without requiring multiple fixed focal planes, thus maintaining simplicity while improving user comfort and reducing vergence-accommodation conflict.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of beam diameter dynamically. By adjusting the diameter of collimated pixel beams passed through the leaky-grating light guide, the system can extend the depth of field and accommodate different virtual distance requirements, resolving the vergence-accommodation conflict without increasing overall device complexity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the depth of field is extended to reduce VAC, then user comfort is improved, but the device complexity increases

Engineering Contradiction:

Improveuser comfortVSAvoidoptical system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a light modifying device as an intermediary component between the projector and the eyepiece. This mediator dynamically adjusts the beam diameter of collimated pixel beams, enabling depth of field extension and reduced vergence-accommodation conflict without requiring a complete redesign of the optical system or addition of multiple focal planes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If virtual content is presented across a wider depth range, then the adaptability is improved, but visual discomfort increases due to VAC

Engineering Contradiction:

Improvedepth range presentationVSAvoidvisual discomfort

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses dynamic adjustment of beam diameter to enable the system to adapt to different virtual depth requirements. By continuously or steplessly adjusting the beam diameter, the system can present virtual content across a wide depth range while maintaining proper accommodation cues, thus improving adaptability without causing visual discomfort.

Inventive Principle:

Principle #15Dynamics

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 reduces VAC in both near-field and far-field virtual depth planes, maintaining user comfort by allowing virtual content to be presented across a wider depth range without clipping planes, thus reducing visual discomfort.

Implementation Method 1

modifying the collimated pixel beam includes at least one of: converging the collimated pixel beam; or reducing a diameter of the collimated pixel beam

Methodology Applied

Scientific EffectOptical beam convergence: Lens

Implementation Method 2

a leaky-grating light guide pupil-expanding eyepiece element

Methodology Applied

Scientific EffectLight guide: Waveguide (optics)

Data Source

PatentUS12436384B2Increased depth of field for mixed-reality display

Publication Date: 2025.10.07 MAGIC LEAP INC

AI summary

Optical systems and methods for operation thereof are disclosed. A delimited zone is defined as a function of distance from the optical system based on a VAC limit, the delimited zone having at least one distance threshold. A virtual distance of a virtual depth plane from the optical system at which a virtual object is to be displayed is determined. It is determined whether the virtual distance is outside the delimited zone by comparing the virtual distance to the at least one distance threshold. A collimated pixel beam associated with the virtual object is generated by a projector of the optical system. The collimated pixel beam is modified to generate a modified pixel beam if the virtual distance is outside the delimited zone. Modifying the collimated pixel beam includes converging the collimated pixel beam and/or reducing a diameter of the collimated pixel beam.