Head-Mounted Lens Mounting Structures With Molded Alignment Tabs
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Solution Overview
Problem
Existing head-mounted devices struggle with accommodating varying interpupillary distances among users, leading to suboptimal image presentation and alignment issues for left and right optical modules.
Innovation Solution
The implementation of multi-element lenses with molded polymer and lens tabs that mate with coplanar mounting surfaces in the lens barrel, along with alignment marks, ensures precise alignment and adjustment of optical modules to accommodate different interpupillary distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lenses are mounted in lens barrels without precise alignment provisions, then assembly is simpler, but image quality deteriorates due to misalignment and optical distortions
Solution Approach 1:
The lens is divided into multiple elements (first lens element and second lens element) that can be separately mounted and aligned. Each lens element has its own mounting provisions, allowing independent positioning and alignment adjustment to achieve precise optical alignment while maintaining manageable assembly complexity.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with molded polymer lens elements that have integrated alignment features. The alignment marks and coplanar mounting surfaces provide passive mechanical alignment guidance, eliminating the need for active adjustment mechanisms while maintaining high alignment precision.
2Adaptability or versatility
If optical modules are fixed in position, then structural stability is improved, but adaptability to different interpupillary distances deteriorates
Solution Approach 1:
The optical modules are made adjustable along the x-axis to accommodate different interpupillary distances. The lens barrels can be positioned at different locations within the housing, transforming the system from static to dynamically adjustable while maintaining stability through defined mounting positions and alignment features.
Solution Approach 2:
The mounting structure is designed to accommodate multiple positions and configurations. The lens barrels can be positioned at different locations, and the lenses can be aligned in various orientations, allowing the same basic structure to serve multiple functions: fixed stability when positioned, and adjustable adaptability when repositioned.
3Ease of manufacture
If lens elements are made from molded polymer with integrated mounting features, then manufacturing ease is improved, but manufacturing precision may deteriorate due to molding tolerances
Solution Approach 1:
The mounting provisions (lens tabs) are merged with the lens elements themselves rather than being separate components. The lens tabs are formed as integral parts of the molded polymer lens elements, combining the optical element and mounting feature into a single piece, which simplifies manufacturing while maintaining precision through the coplanar mounting surfaces.
Solution Approach 2:
The patent uses coplanar mounting surfaces and alignment marks that provide reference planes for precise positioning. By changing the geometric parameters of the molded features (coplanar surfaces, specific tab geometries), the design compensates for typical molding tolerances and achieves the required alignment precision.
Data Source
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AI summary
A head-mounted device may have optical modules that present images to the user's left and right eyes. The optical modules may move with respect to each other to accommodate different user interpupillary distances. Each optical module may have a lens barrel, a display coupled to the lens barrel that generates an image, and a lens mounted to the lens barrel through which the image is viewable from an eye box. The lens may be a multi-element lens formed from molded lens elements such as molded polymer lens elements. A lens element may be provided with protrusions that form lens tabs. The lens tabs may have coplanar lens tab surfaces that mate with corresponding coplanar mounting surfaces in the lens barrel. Alignment marks may be formed on the protrusions and/or other portions of the lens.