Variable-Focus Lens Dampening for Mixed Reality Vergence Conflict

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Solution Overview

Problem

Mixed-reality systems often cause user discomfort due to vergence-accommodation conflict, where the eyes' focus depth differs from the virtual content's presentation depth, leading to distortions and disorientation, especially when users are in motion or in complex environments.

Innovation Solution

The system employs a variable-focus lens that adjusts its focus depth to match the user's vergence depth, with selective dampening of adjustments based on motion characteristics and environmental conditions to minimize distortions and maintain user safety and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If variable-focus lens adjustments are made to match vergence depth, then vergence-accommodation conflict is reduced, but distortions to real-world and virtual objects occur

Engineering Contradiction:
Improvevergence-accommodation conflict reductionVSAvoidvisual distortions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically changes the focal parameter of the variable-focus lens based on the detected triggering condition. When motion characteristics exceed thresholds or geometric complexity is high, the system prevents focal length changes that would cause distortions, while allowing adjustments when conditions are stable, thus resolving the contradiction between reducing vergence-accommodation conflict and avoiding visual distortions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If variable-focus lens continuously adjusts to vergence depth, then focus accuracy is improved, but user discomfort during motion increases

Engineering Contradiction:
Improvefocus depth accuracyVSAvoiduser discomfort during motion
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system implements dynamic control of the variable-focus lens by continuously monitoring motion characteristics (acceleration, velocity, position) and geometric complexity, and adjusting the lens focal length accordingly. The system transitions from static continuous adjustment to dynamic conditional adjustment, allowing focus tracking when stable and preventing adjustments when motion or complexity triggers discomfort.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from motion sensors and environmental analysis to control the variable-focus lens. By detecting triggering conditions related to user motion and scene complexity, the system provides feedback to the lens control mechanism to either allow or prevent focal adjustments, thereby reducing user discomfort during motion while maintaining focus accuracy when appropriate.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If variable-focus lens makes full adjustments to eliminate conflict, then visual comfort is improved, but environmental stability perception deteriorates

Engineering Contradiction:
Improvevisual comfortVSAvoidenvironmental perception stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The system selectively applies parameter changes to the lens focal length based on environmental conditions. When geometric complexity is high or motion triggers are detected, the system maintains or reduces focal adjustments to preserve environmental stability perception. When conditions are favorable, the system allows full adjustments to maximize visual comfort, thus resolving the contradiction between comfort and stability.

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

This approach reduces user discomfort and safety risks by balancing vergence-accommodation conflict correction with the need to maintain a stable perception of the environment, particularly during motion or in complex scenes, thereby enhancing the mixed-reality experience.

Implementation Method 1

a variable-focus lens for providing focus on virtual content viewed by a user

Methodology Applied
Scientific EffectLens focusing: Lens

Data Source

PatentEP4059214B1Automated variable-focus lens control to reduce user discomfort in a head-mounted display
Publication Date: 2024.10.23 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4059214B1 patent drawingFigure 1A~1B
  • EP4059214B1 patent drawingFigure 2~3
  • EP4059214B1 patent drawingFigure 4~5

AI summary

Systems and methods for controlling variable-focus functionality to reduce user discomfort in a mixed-reality system implement acts of obtaining a vergence depth of a gaze of a user, determining that the variable-focus lens for providing focus on virtual content viewed by the user is currently configured to provide focus at a depth that differs from the vergence depth, detecting that a triggering condition is present, and, in response to so detecting, selectively dampening an adjustment made to the variable-focus lens. In some implementations, the dampening causes the adjustment made to the variable-focus lens to reconfigure the variable-focus lens to provide focus at a depth that differs from the vergence depth.