Optical Module Actuation With Compound Planetary Gearboxes for IPD Adjustment

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Solution Overview

Problem

Existing head-mounted devices struggle to accommodate variations in interpupillary distances among users, leading to suboptimal image presentation and user comfort.

Innovation Solution

Incorporating adjustable left-eye and right-eye optical modules with compound planetary gearboxes and motors, allowing for precise movement and alignment to match individual user interpupillary distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed optical module positions are used in head-mounted devices, then device structure is simple, but the device cannot accommodate variations in interpupillary distances among users

Engineering Contradiction:

Improveaccommodation of interpupillary distance variationsVSAvoidoptical module adjustment mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by transforming the fixed optical module positions into adjustable, movable positions. Optical modules are made movable relative to the head-mounted device housing through adjustment mechanisms, allowing the system to adapt to different interpupillary distances. This enables the device to transition from a static configuration to a dynamic one that can be adjusted based on user-specific requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements universality by designing a single head-mounted device that can serve multiple users with different interpupillary distances. The adjustment mechanisms enable the optical modules to be repositioned to accommodate various user configurations, making the device universally applicable across different users rather than being dedicated to a single fixed configuration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If optical modules are made movable to adjust interpupillary distances, then user comfort and image quality improve, but device structure and control complexity increase

Engineering Contradiction:

Improveoptical module adjustabilityVSAvoidactuator and gearbox system

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies mechanics substitution by replacing manual adjustment mechanisms with automated actuators. Motors drive the optical modules through mechanical linkages, eliminating the need for manual intervention. This substitution of mechanical systems with automated control mechanisms improves ease of operation while managing the inherent complexity through systematic design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements the nested doll principle through the use of compound planetary gearboxes. These gearboxes contain multiple gear stages nested within each other, with planet gears arranged in concentric configurations. This nested arrangement allows for high reduction ratios in a compact form factor, enabling precise control of optical module positions without requiring excessive space or mechanical complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Volume of moving object

If high reduction ratio gearboxes are used to reduce actuator size, then actuator footprint decreases, but gearbox complexity increases

Engineering Contradiction:

Improveactuator sizeVSAvoidgearbox structure

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent applies the nested doll principle by designing compound planetary gearboxes with nested gear arrangements. Multiple planet gear stages are arranged concentrically, with inner planet gears meshing with outer planet gears. This nested configuration achieves high reduction ratios (e.g., 10:1 or higher) within a compact volume, significantly reducing actuator footprint while systematically managing the inherent mechanical complexity through standardized gear design.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent implements merging by combining multiple gear functions into a single integrated planetary gearbox unit. The compound planetary design merges the functions of multiple gear stages into one compact mechanism, eliminating the need for separate gearboxes or multiple actuators. This consolidation reduces overall system complexity while achieving the required high reduction ratios for compact actuator design.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250172813A1Electronic Devices with Movable Components

Publication Date: 2025.05.29 APPLE INC

AI summary

Electronic devices such as head-mounted electronic devices may include displays for presenting images to users. To accommodate variations in the interpupillary distances associated with different users, a head-mounted device may have left-eye and right-eye optical modules that move with respect to each other with actuators. The actuators may include motors, compound planetary gearboxes, and lead screws that move the optical modules. In particular, the compound planetary gearboxes may have high reduction ratios to reduce the size of the actuators while providing sufficient torque to move the optical modules. The compound planetary gearboxes may include first and second planet gears coupled to common shafts, and carriers that carry the planet gears and that drive the lead screws. The second planet gears may have smaller diameters than the first planet gears, and the second planet gears may mesh with teeth on a ring gear, to provide the high reduction ratio.