Optical Combiner Lens Spacers for Wearable HUD Weight Reduction
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Solution Overview
Problem
Current wearable heads-up displays face challenges in providing a sufficient field of view while being compact and lightweight, especially when integrating prescription lenses, due to the bulkiness and weight of existing optical combiner designs.
Innovation Solution
An optical combiner lens design featuring a lightguide and lens stack with microbeads or micropillars as spacers to maintain a medium gap, minimizing evanescent coupling and scattering, and a seal that wraps around the edges to secure the components, allowing for a thinner and lighter construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional optical combiner designs are used, then optical performance is maintained, but the device becomes bulky and heavy
Solution Approach 1:
The patent merges the lens and lightguide into a single integrated optical combiner lens assembly, where the lightguide is positioned in direct contact with or very close to the lens. This eliminates the need for separate mounting structures and reduces the overall thickness and weight of the optical components while maintaining optical performance.
Solution Approach 2:
The lightguide is nested within or integrated into the lens structure, with the lightguide occupying the space between the lens and the user's eye. This nested arrangement allows the optical components to share the same physical envelope, reducing the overall device complexity and weight without compromising optical functionality.
2Length of moving object
If the gap between lens and lightguide is reduced, then the device becomes thinner, but evanescent coupling and scattering increase
Solution Approach 1:
The patent introduces an intermediary layer or coating at the interface between the lens and lightguide that prevents evanescent coupling and scattering while allowing the gap to be minimized. This intermediary structure enables thin design without the harmful optical effects that would normally occur at reduced spacing.
3Weight of moving object
If optical components are made thinner, then weight is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates alignment features and mounting structures that are built into the lens and lightguide during manufacturing, ensuring precise alignment is achieved automatically during assembly. This preliminary preparation of alignment mechanisms reduces the need for post-assembly adjustments and maintains manufacturing precision even as component thickness is reduced.
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 design enhances the field of view and reduces the weight of wearable heads-up displays by minimizing the thickness of the optical components while maintaining optical performance, making them more comfortable for prolonged wear.
Implementation Method 1
maintain the gap at a set height... minimizing evanescent coupling and scattering
Implementation Method 2
propagates along the length of the guide substrate by total internal reflection
Implementation Method 3
refractive, or diffractive optical elements to redirect light from a light source to a target
Implementation Method 4
reflect, refract, or diffract light, within the guide substrate
Data Source
AI summary
An optical combiner lens includes a lens and a lightguide with a gap defined between the lens and the lightguide. Spacers are disposed in the gap to maintain the gap at a set height. A method of making the optical combiner lens and a wearable heads-up display including the optical combiner lens are disclosed.