Head-Motion IPD Compensation for Augmented Reality Viewing

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Solution Overview

Problem

Existing augmented reality near-eye displays face challenges in being lightweight, low-cost, and maintaining a wide virtual image field of view while minimizing vergence-accommodation mismatch, particularly when users change their head positions.

Innovation Solution

A viewing system that compensates for interpupillary distance (IPD) adjustments based on head motion, utilizing a head-worn component, hand-held controller, and auxiliary computing to correlate IPD with head orientation and position, employing cameras and IMUs to automatically adjust virtual reality presentations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If interpupillary distance is measured for each user but not correlated to head movement, then user-specific IPD accuracy is improved, but vergence-accommodation mismatch increases when users change head positions

Engineering Contradiction:
ImproveIPD measurement accuracyVSAvoidvergence-accommodation match
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system transitions from a static IPD measurement to a dynamic IPD adjustment system that correlates IPD with head orientation and position. The IPD is no longer fixed but varies dynamically based on detected head movements, resolving the contradiction between initial measurement accuracy and ongoing reliability during head motion.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by using motion sensors to detect head position changes and automatically adjusting the IPD accordingly. This closed-loop approach ensures that the IPD remains accurate and reliable even when users change head positions, maintaining vergence-accommodation match throughout the viewing experience.

Inventive Principle:
Principle #23Feedback

2Weight of moving object

If head-mounted display is made lightweight with small form-factor, then wearability and comfort are improved, but field of view and image quality may be limited

Engineering Contradiction:
Improvehead-mounted display weightVSAvoidvirtual image field of view
Core Design Contradiction:
Weight of moving objectVSArea of stationary object

Solution Approach 1:

The system changes the parameter of IPD to dynamically adapt to head movements, allowing a compact design to maintain wide field of view and image quality. By adjusting IPD based on head orientation, the system compensates for the limitations of a small form-factor without requiring a larger or heavier optical system.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple focal planes are implemented, then practicality for various use-cases is improved, but vergence-accommodation mismatch increases

Engineering Contradiction:
Improveuse-case versatilityVSAvoidvergence-accommodation match
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system makes IPD dynamic rather than fixed, allowing it to adapt to different focal planes and use-cases. This dynamic adjustment maintains vergence-accommodation match across multiple focal distances, enabling versatile functionality without the typical mismatch problems associated with multi-focal displays.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3831058B1A viewing system with interpupillary distance compensation based on head motion
Publication Date: 2025.10.08 MAGIC LEAP INC
  • EP3831058B1 patent drawingFigure 1
  • EP3831058B1 patent drawingFigure 2
  • EP3831058B1 patent drawingFigure 3

AI summary

The invention provides a viewing system including an augmented reality system that generates a visual presentation to a user based at least in part on an IPD of the user, and an IPD compensator that adjusts the visual presentation based on an IPD compensation factor.