HMD Virtual Distance Adjustment for Visual Comfort

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Solution Overview

Problem

Head-mounted display devices (HMDs) lack flexibility in adjusting the distance between virtual and real displays, requiring constant adjustments and causing visual discomfort due to inadequate accommodation efforts, especially when switching between virtual and real-world visualization.

Innovation Solution

A method to determine a comfortable virtual distance of visualization by assessing the wearer's dynamic accommodative facility, calculating the comfort amplitude of accommodation, and validating or changing the accommodation value to reduce the gap between virtual and real display distances, allowing seamless switching between virtual and real displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the HMD displays virtual information content at a fixed distance, then the virtual display is simple to implement, but the wearer experiences visual discomfort when switching between virtual and real displays due to accommodation mismatch

Engineering Contradiction:
Improvevisual comfortVSAvoidaccommodation adjustment mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the virtual display distance adjustable rather than fixed. The system dynamically adapts the virtual image distance based on the wearer's accommodative facility and the distance of real objects being viewed. This allows the HMD to transition between different visualization distances, enabling comfortable switching between virtual and real displays without requiring constant manual adjustment by the wearer.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of virtual display distance to match the wearer's accommodative capabilities. By measuring the wearer's amplitude of accommodation and using this information to set the virtual image distance, the system optimizes visual comfort. The virtual display distance is no longer a fixed parameter but is dynamically adjusted based on individual wearer characteristics and viewing conditions.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the HMD allows flexible adjustment of virtual display distance, then the wearer can comfortably switch between virtual and real displays, but the system becomes more complex requiring measurement and calculation of accommodative facility

Engineering Contradiction:
Improveflexibility in display distanceVSAvoidmeasurement and calculation system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs self-service by automatically measuring and calculating the wearer's accommodative facility without requiring manual input or complex user interaction. The HMD incorporates sensors and processing capabilities that autonomously determine the optimal virtual display distance based on the wearer's physiological characteristics, eliminating the need for manual accommodation adjustment while maintaining high adaptability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements feedback mechanisms where the system continuously monitors the wearer's visual response and accommodative facility. This feedback information is used to dynamically adjust the virtual display distance, creating a closed-loop system that adapts to changing viewing conditions. The feedback loop ensures optimal visual comfort while maintaining flexibility in display distance adjustment.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the HMD is customized to the wearer's specific accommodative characteristics, then visual comfort is optimized, but the manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improvevisual comfortVSAvoidcustomization process
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by measuring and characterizing the wearer's accommodative facility during the initial setup process. This preliminary measurement allows the system to pre-configur the virtual display distance and optical parameters to match the wearer's specific needs. By performing this customization during the initial configuration rather than requiring complex manufacturing processes, the system achieves personalized visual comfort while maintaining ease of manufacture through software-based optimization rather than hardware customization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3119266B1Methods for augmented reality
Publication Date: 2021.04.14 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP3119266B1 patent drawingFigure 1~2
  • EP3119266B1 patent drawingFigure 3
  • EP3119266B1 patent drawingFigure 4~5

AI summary

The invention relates to methods for augmented reality. The invention relates more particularly to methods for improving the visual comfort of a wearer equipped with a head-mounted display device.