Actuator Mechanism for Head-Mounted Display Interpupillary Adjustment

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Solution Overview

Problem

Existing head-mounted displays struggle to accommodate varying inter-pupillary distances among users, leading to discomfort and poor fit, as current adjustment mechanisms primarily focus on circumferential fit rather than addressing differences in facial features.

Innovation Solution

A head-mounted display with an actuator mechanism that includes a movement mechanism with a lead screw and nut assembly, a locking-release mechanism using springs or electromagnetic components, and a dampening mechanism to adjust and secure optical components, allowing for precise alignment and protection during dynamic events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing head-mounted displays use fixed adjustment mechanisms for circumferential fit, then the device can be adjusted for head size, but it cannot accommodate differences in inter-pupillary distance among users

Engineering Contradiction:
Improveaccommodation of inter-pupillary distanceVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuator mechanism serves multiple functions: it adjusts the interpupillary distance of optical components, positions optical elements relative to the user's eyes, and can lock/release to maintain settings. This multi-functionality addresses the limitation of existing single-purpose adjustment mechanisms while managing device complexity through integrated design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces traditional manual mechanical adjustment mechanisms with an actuator system that can be electrically or electronically controlled. This substitution enables more precise and programmable adjustment of interpupillary distance while reducing the mechanical complexity of manual adjustment components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If a movement mechanism is used to adjust optical component position, then precise alignment is achieved, but the mechanism becomes vulnerable to damage during dynamic events such as drops or impacts

Engineering Contradiction:
Improveoptical component alignment precisionVSAvoidmechanism durability during dynamic events
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The dampening mechanism is positioned to absorb and dissipate impact forces before they can damage the movement mechanism or optical components. This cushioning effect protects the precision alignment system during drops or impacts while maintaining adjustment capability during normal use.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The dampening mechanism acts as an intermediary between external dynamic forces and the movement mechanism. It mediates the transmission of impact forces, protecting the precision alignment system from damage while allowing the adjustment function to remain operational.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the movement mechanism remains engaged during dynamic events, then positioning is maintained, but the mechanism experiences excessive force that can cause damage

Engineering Contradiction:
Improveoptical component position stabilityVSAvoidmechanism strength under dynamic load
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The locking-release mechanism transitions the movement mechanism from a static engaged state to a dynamic disengaged state during detected dynamic events. This dynamic response allows the system to maintain stability during normal use while protecting against excessive forces during impacts or drops.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system detects dynamic events beforehand and preemptively disengages the movement mechanism to prevent damage. This preliminary anti-action counteracts the potential harmful effect of excessive forces on the engaged mechanism before the damage can occur.

Inventive Principle:
Principle #9Preliminary anti-action

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 enables precise adjustment of optical components to fit unique facial features, enhancing comfort and performance by allowing controlled repositioning and protection during handling or wear, addressing the limitations of existing adjustment mechanisms.

Implementation Method 1

The movement mechanism can comprise a lead screw and a nut assembly, the nut assembly configured to translate along the lead screw based on rotation of the lead screw

Methodology Applied
Scientific EffectLead screw mechanism: Screw

Implementation Method 2

The locking-release mechanism can include a spring that linearly biases one of the first and second portions of the nut assembly against the lead screw

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 3

The dampening mechanism can comprise an electromagnetic component configured to generate attraction between the nut assembly and the lead screw during the dynamic event

Methodology Applied
Scientific EffectElectromagnetic attraction: Electromagnet

Implementation Method 4

The dampening mechanism can comprise an electromagnetic component configured to repel the movement mechanism from end portions of the actuator during the dynamic event

Methodology Applied
Scientific EffectElectromagnetic repulsion: Electromagnetic Propulsion

Data Source

PatentEP3914957B1Adjustment mechanism for head-mounted display
Publication Date: 2023.11.22 APPLE INC
  • EP3914957B1 patent drawingFigure 1
  • EP3914957B1 patent drawingFigure 2A~2B
  • EP3914957B1 patent drawingFigure 3A~3B

AI summary

A head-mounted display includes an optical assembly and an actuator. The actuator includes a movement mechanism configured to adjust a position of an optical component within the optical assembly, a locking-release mechanism configured to modify operation of the movement mechanism upon detection of a dynamic event, and a dampening mechanism configured to control positional changes of the optical component during the dynamic event.