VR Lens Module Gear-Rack IPD Adjustment for Synchronized Precision
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Solution Overview
Problem
Existing VR glasses suffer from low adjustment accuracy, unsynchronized lens modules, and large volume occupation due to mechanical threads for interpupillary distance adjustment, leading to a poor user experience.
Innovation Solution
An interpupillary distance adjusting device with a driving module that synchronously adjusts the left and right lens modules using a gear and rack mechanism, integrated with a multi-stage planetary gearbox for high precision and small volume, featuring parallel racks and a plastic frame for stability and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical threads are used to adjust interpupillary distance, then the structure is simple, but the adjustment accuracy is low and synchronization between lens modules is poor
Solution Approach 1:
The patent replaces the traditional mechanical thread-based adjustment system with a motor-driven gear and rack mechanism. Two synchronous motors drive two racks through gear transmissions, enabling precise control of lens module positions. This substitution eliminates the low precision and synchronization issues of mechanical threads while maintaining structural feasibility.
Solution Approach 2:
The patent introduces a control unit as an intermediary that receives adjustment signals and coordinates the operation of two synchronous motors. This control intermediary ensures synchronized movement of left and right lens modules, solving the synchronization problem inherent in independent mechanical thread adjustments.
2Productivity
If a long screw with left-hand and right-hand threads is used, then the adjustment mechanism can move lenses, but the volume occupation is large and efficiency is lost
Solution Approach 1:
The patent replaces the long screw mechanism with compact motor-gear-rack assemblies. The synchronous motors with planetary gearboxes provide high reduction ratios in a small space, driving the racks to move lens modules efficiently. This eliminates the need for a long screw while improving adjustment speed and reducing the overall volume of the adjustment mechanism.
Solution Approach 2:
The patent employs planetary gearboxes that nest multiple gear stages within a compact structure. The sun gear, planet gears, and ring gear are arranged concentrically, achieving high gear reduction ratios in a minimal space. This nesting principle allows efficient power transmission without occupying excessive volume.
3Reliability
If two separate motors are used to drive lens modules, then adjustment can be performed, but synchronization and stability are unsatisfied
Solution Approach 1:
The control unit serves as an intermediary that receives a single adjustment signal and simultaneously controls both synchronous motors. This ensures that the left and right lens modules move synchronously by the same amount, maintaining stability and reliability of the interpupillary distance adjustment.
Solution Approach 2:
The patent incorporates encoders on the output shafts of both synchronous motors to provide position feedback to the control unit. This feedback mechanism allows the control unit to monitor and adjust motor positions in real-time, ensuring synchronized movement and enhancing the reliability of the adjustment system.
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
Achieves high adjustment accuracy, small volume occupation, and improved stability, resulting in a better user experience through synchronized lens movement.
Implementation Method 1
a first gear member rotatably disposed in the frame and in transmission connection with the driving unit, a second gear member rotatably disposed in the frame and engaged with the first gear member
Implementation Method 2
a first rack engaged with the first gear member, and a second rack engaged with the second gear member
Data Source
AI summary
An interpupillary distance adjusting device applied to VR glasses, the VR glasses include bracket body, first and second lens modules, the device includes driving module fixed to the bracket body and located between the first and second lens modules. The driving module is configured to drive the first and second lens modules to move towards or away from each other to realize interpupillary distance adjustment. The driving module includes frame, driving unit, first and second gear members, first and second racks parallel to each other. An end of the first rack is fixed to the first lens module, an end of the second rack is fixed to the second lens module. Compared with the related art, the interpupillary distance adjusting device can automatically and synchronously adjust the interpupillary distance, with high adjustment accuracy, small volume occupation, high driving efficiency, high stability, and good user experience.