HMD Focus Adjustment via Cam-Driven Linear Optical Displacement
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Solution Overview
Problem
Existing head-mounted display (HMD) devices are complex and inconvenient to use, particularly for users with ametropia, as they require individual adaptation or specialized lenses, and existing focus adjustment mechanisms are technically complex and uncomfortable to operate.
Innovation Solution
The HMD device features adjustable imaging optical systems for each eye with a support frame, an optical element, a deflecting element, and a drive unit with a cam mechanism and adjusting wheels, allowing for dioptric equalization and focus adjustment via a cam gear system that translates rotational movement into linear displacement of the optical element, enabling easy and precise adjustment without projecting components outward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the HMD device is attached to spectacles frame or lens for ametropic correction, then the device can accommodate users with ametropia, but the device becomes complex and uncomfortable to wear
Solution Approach 1:
The patent implements a dynamic focus adjustment mechanism where the optical element can be moved along the optical axis through a cam mechanism driven by an adjusting wheel. This allows the optical system to adapt to different ametropic conditions dynamically, eliminating the need for multiple fixed corrective lenses or complex attachment mechanisms to spectacles.
2Ease of operation
If knurled screws are mounted laterally on the HMD device for focus adjustment, then focus adjustment is enabled, but the screws project at both sides of the head causing discomfort
Solution Approach 1:
The adjusting wheel is positioned in a different spatial arrangement compared to conventional lateral knurled screws. The cam mechanism translates rotational movement into linear displacement of the optical element, allowing the adjustment control to be positioned ergonomically without projecting components outward, thus eliminating discomfort while maintaining ease of operation.
3Ease of operation
If a toothed wheel gear assembly with cam gear is used for focus adjustment, then focus adjustment is achieved, but the arrangement becomes technically complex
Solution Approach 1:
The patent extracts and eliminates unnecessary intermediate components from the focus adjustment mechanism. Instead of using a complex toothed wheel gear assembly, the invention employs a simplified cam mechanism where the adjusting wheel directly actuates the cam to move the optical element, removing redundant gearing while maintaining the essential focus adjustment function.
4Ease of operation
If multiple displacement elements project outwardly for coarse and fine adjustment, then focus adjustment is enabled, but the arrangement has large length expansion and is difficult to operate
Solution Approach 1:
The patent merges the coarse and fine adjustment functions into a single integrated adjusting wheel mechanism. The cam mechanism provides continuous variable adjustment that encompasses both coarse and fine focus changes, eliminating the need for separate displacement elements and reducing the overall length expansion 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
The solution provides a simple, cost-effective, and ergonomic method for users to adjust the focus, allowing for comfortable operation and precise dioptric compensation within a compact design, reducing the need for external lenses and minimizing mechanical stress on the optics.
Implementation Method 1
each of the drive units further including a cam mechanism for coupling the adjusting wheel to the receptacle frame so as to translate an input rotational movement of the adjusting wheel into an output linear movement of the receptacle frame
Implementation Method 2
Each imaging optic so images an image, which is generated in the object plane, that a user can observe the image in an image plane
Data Source
AI summary
An HMD device has an imaging optic for the right eye and an imaging optic for the left eye. Each imaging optic so images an image, which is generated in the object plane, that the image can be observed by a user in an image plane and each of the imaging optics includes an optical element (23) and a deflecting element (25) mounted downstream of the optical element (23). An image transducer (24) and the optical element (23), which follows the image transducer (24), are held by a linearly guided receptacle frame (15) moveable via a drive unit. A linear movement in the direction of an optical axis takes place. Adjusting wheels (4, 5) are mounted on respective sides of the image window for the right and left eyes. Each of the adjusting wheels (4, 5) is coupled mechanically to a corresponding cam curve. Each cam curve translates a rotational movement of the adjusting wheel (4, 5) into an output end linear movement of the receptacle frame (15).