Lateral-Offset Reflector for Flexible Waveguide Combiner Layouts
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Solution Overview
Problem
Conventional waveguide combiners in augmented reality eyewear face limitations in positioning the incoupler and exit pupil expander due to their aligned alignment, restricting the shape and size of ophthalmic lenses and requiring unfavorable positioning of the incoupler outside the temple region.
Innovation Solution
Incorporating an offset reflector with reflective facets between the incoupler and exit pupil expander to decouple their positional constraints, allowing the incoupler to be positioned in the temple area while enabling the exit pupil expander to fit various ophthalmic lens shapes and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the incoupler and exit pupil expander are aligned, then the optical path is simplified, but the positioning flexibility and lens design freedom are restricted
Solution Approach 1:
An offset reflector is introduced as an intermediary optical element between the incoupler and exit pupil expander. This reflector decouples the positional constraints by redirecting light at an offset angle, allowing the incoupler and exit pupil expander to be positioned independently while maintaining proper optical alignment. The reflector acts as a mediator that transforms the rigid aligned configuration into a flexible offset configuration.
Solution Approach 2:
The offset reflector introduces a new spatial dimension to the optical path by reflecting light at an angle that creates lateral offset. This dimensional change allows the optical components to be arranged in a non-aligned configuration while still achieving proper light delivery, thereby increasing positioning flexibility without compromising optical functionality.
2Ease of operation
If the incoupler is positioned in the temple area, then the device fits better within eyewear, but the exit pupil expander positioning becomes constrained
Solution Approach 1:
The offset reflector serves as a mediator that enables the incoupler to be positioned in the temple area while still allowing the exit pupil expander to be positioned optimally for various lens shapes. The reflector redirects light from the temple-area incoupler to the appropriately positioned exit pupil expander, decoupling the positioning constraints and enabling better eyewear integration.
Solution Approach 2:
The optical system is segmented into distinct functional modules (incoupler, offset reflector, exit pupil expander, outcoupler) that can be independently positioned. This segmentation allows the incoupler to be optimized for temple area placement while the exit pupil expander is independently positioned to match different lens geometries, improving overall device adaptability.
3Ease of manufacture
If conventional aligned waveguide combiners are used, then the optical design is straightforward, but image rotation issues occur
Solution Approach 1:
The offset reflector acts as an intermediary element that introduces controlled angular offset to the optical path. This offset compensates for image rotation by redirecting light at a specific angle that counteracts the rotational distortion, thereby eliminating image rotation issues while maintaining relatively simple optical design through the use of a single reflective element.
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 configuration optimizes the positioning of optical components, enabling flexible lens designs and reducing image rotation issues, thereby enhancing the usability and versatility of augmented reality eyewear.
Implementation Method 1
an offset reflector facet disposed in the optical path between the incoupler and the exit pupil expander
Implementation Method 2
propagates along the waveguide via total internal reflection (TIR)
Data Source
AI summary
Embodiments of techniques presented herein facilitate more optimal positioning of an incoupler and exit pupil expander within an eyeglass-type near-eye display system that includes an optical waveguide combiner. In certain embodiments, the optical waveguide combiner comprises an incoupler; an outcoupler; an exit pupil expander that comprises one or more reflective facets and is disposed in an optical path between the incoupler and the outcoupler; and an offset reflector facet disposed in the optical path between the incoupler and the exit pupil expander.