Single Knob Mechanism for HMD Diopter and Interpupillary Adjustment
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Solution Overview
Problem
Existing head-mounted displays require complex structures to adjust diopter and interpupillary distance simultaneously, leading to increased volume, weight, and misplacement issues affecting display quality, especially for users with varying eye distances.
Innovation Solution
A compact head-mounted display design featuring a diopter and interpupillary distance adjustment mechanism that uses a single knob for rotation and sliding operations, incorporating a drive assembly with a cam and tension spring, and a knob assembly with a turntable and displacement restriction ball, allowing independent adjustments of diopter and interpupillary distance without moving the eyepieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two lens tubes are driven to slide along X-axis direction on the X-axis bracket to adjust the center distance between the two lenses for adapting the users with different interpupillary distances, then the interpupillary distance adjustment is achieved, but the structure becomes complex and the volume increases
Solution Approach 1:
The patent combines the diopter adjustment mechanism and interpupillary distance adjustment mechanism into a single integrated structure. The eyepiece tube is integrated with the lens tube, and both adjustments are achieved through coordinated movement of the same components rather than separate mechanisms, thereby reducing structural complexity while maintaining both adjustment functions.
Solution Approach 2:
The X-axis bracket and lens tube assembly serve multiple functions: they simultaneously enable diopter adjustment (through axial movement) and interpupillary distance adjustment (through lateral movement). This multi-functionality eliminates the need for separate dedicated mechanisms for each adjustment type, reducing overall device complexity.
2Adaptability or versatility
If two lens tubes are driven to slide along X-axis direction on the X-axis bracket to adjust the center distance between the two lenses, then the interpupillary distance adjustment is achieved, but the volume of the head-mounted display increases
Solution Approach 1:
The patent merges the diopter adjustment and interpupillary distance adjustment functions into a compact integrated structure. The eyepiece tube and lens tube are combined, and both adjustments share common structural elements like the X-axis bracket and Y-axis bracket, significantly reducing the overall volume compared to separate adjustment mechanisms.
Solution Approach 2:
The patent employs a nested structure where the lens tube is positioned within the eyepiece tube, and both are mounted on the compact X-axis and Y-axis brackets. This nesting arrangement allows multiple adjustment functions to be accommodated in a small volume, making the head-mounted display compact and wearable.
3Adaptability or versatility
If the lenses or lens tubes at both sides are moved at the same time to adjust the interpupillary, then the interpupillary distance adjustment is achieved, but misplacement between the optical center and the display center occurs thus directly affecting the display effect at the screen edge
Solution Approach 1:
The patent segments the adjustment functions: the Y-axis bracket controls the longitudinal position of the X-axis bracket (and thus the lenses) independently, while the X-axis bracket controls the lateral position (interpupillary distance). This segmentation allows the optical center to remain aligned with the display center during interpupillary adjustment, as the longitudinal position can be independently maintained.
Solution Approach 2:
The patent employs a dynamic two-stage adjustment mechanism where the Y-axis bracket and X-axis bracket can move independently. During interpupillary adjustment, the system dynamically maintains the longitudinal position relationship between the lenses and display, ensuring optical center alignment is preserved while allowing lateral separation adjustment.
4Adaptability or versatility
If a Y-axis adjustment component is used for driving the X-axis bracket to slide relative to the Y-axis bracket along the Y-axis direction for adjusting the longitudinal distance between the two lenses and the display panel, then the diopter adjustment is achieved, but the movement of the lenses or lens tubes would change the distance between the lenses or lens tubes and the display screen at the same time, while changing the eye distance, that is, changing the eye distance would reduce the adjustment precision of the diopter thus affecting the viewing performance
Solution Approach 1:
The patent employs a dynamic two-stage adjustment mechanism where the Y-axis bracket controls longitudinal position and the X-axis bracket controls lateral position. During diopter adjustment, the system dynamically maintains constant eye distance by coordinating the movements, ensuring that only the longitudinal distance between lenses and display changes while the eye-lens distance remains stable, thereby preserving adjustment precision.
Solution Approach 2:
The patent implements a feedback mechanism where the position of the Y-axis bracket and X-axis bracket are coordinated to maintain constant eye distance during diopter adjustment. The system monitors and adjusts the lateral position to compensate for any changes in eye distance, ensuring precise diopter adjustment is maintained throughout the adjustment range.
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 solution simplifies the structure, reduces weight, and enhances user experience by allowing precise adjustments with ease, maintaining clear images and reducing the complexity of the display mechanism, resulting in a more comfortable and effective wearable device.
Implementation Method 1
a drive assembly and a knob assembly, wherein the diopter and interpupillary distance adjustment mechanism employs a rotation operation and a sliding operation of a same knob assembly
Implementation Method 2
a drive assembly with a cam and tension spring
Data Source
AI summary
A head-mounted display apparatus is disclosed which including a main frame arranged with left and right display screens, left and right eyepieces arranged in correspondence with the left and right display screen. The main frame is further arranged with a diopter and interpupillary distance adjustment mechanism for adjusting a distance between the display screens and the eyepieces and a distance between two eyepieces at each side. The diopter and interpupillary distance adjustment mechanism employs a rotation operation and a sliding operation of a same knob assembly for achieving adjustments of a diopter and an interpupillary distance of the head-mounted display apparatus. That is, not only the operation is easier, but also the product structure is simplified, so that the head-mounted display apparatus has a more compact structure, lighter weight and more comfortable and convenient use.