Metasurface Lens Stack on Waveguide Combiners for AR/VR
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Solution Overview
Problem
The manufacturing of virtual reality (VR) and augmented reality (AR) glasses is hindered by the need for multiple lenses, leading to a heavy and bulky form factor, increased manufacturing time and cost due to post alignment processes, and discomfort for users with prescription eyeglasses.
Innovation Solution
The use of a stacked lens configuration that includes a waveguide combiner with gratings and metasurfaces, which reduces weight and allows for integrated prescription lenses, eliminating the need for post alignment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple lenses are used in VR and AR glasses to focus virtual images and assist users with prescription requirements, then the functional requirements are met, but the weight and bulk of the device increase
Solution Approach 1:
The patent combines multiple separate lenses (waveguide combiner, convex lens, concave lens, and prescription lens) into a single integrated stacked lens assembly. The lenses are optically coupled together with minimal spacing, effectively merging their functions into one compact unit that satisfies multiple optical requirements while reducing overall device weight and bulk.
2Manufacturing precision
If multiple lenses are spaced apart to achieve proper optical focusing, then the optical function is improved, but the device becomes heavy and bulky
Solution Approach 1:
The patent implements a nested lens configuration where the convex lens, concave lens, and prescription lens are stacked in close proximity to each other along the optical path. This nested arrangement allows each lens to perform its specific optical function while occupying minimal space, achieving proper optical focusing without increasing device volume significantly.
3Reliability
If multiple lenses are used with spacing between them, then optical performance is achieved, but manufacturing complexity and cost increase due to post alignment processes
Solution Approach 1:
The patent merges multiple lenses into a pre-aligned stacked assembly where the lenses are optically coupled together during the manufacturing process. This integration eliminates the need for complex post-alignment procedures, as the lenses are positioned and secured relative to each other in the stacking process itself, thereby reducing manufacturing complexity while maintaining optical performance.
4Adaptability or versatility
If traditional multiple lens arrangements are used, then optical functions are fulfilled, but manufacturing time and cost increase
Solution Approach 1:
The patent performs preliminary alignment of the multiple lenses during the manufacturing process by stacking and optically coupling them together before final assembly. This preliminary action ensures that the optical alignment is established during production rather than requiring time-consuming post-manufacturing adjustment, thereby improving manufacturing efficiency while fulfilling all optical functions.
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 decreases the weight of the glasses, improves user comfort by accommodating prescription lenses, and reduces manufacturing time and cost by eliminating the need for post alignment processes.
Implementation Method 1
a first plurality of gratings disposed on a first surface of a substrate and a second plurality of gratings disposed on a second surface of the substrate
Implementation Method 2
a first metasurface coupled to the first encapsulation layer. The first metasurface includes a first plurality of optical device structures
Data Source
AI summary
Embodiments of the present application generally relate to augmented reality and virtual reality glasses having stacked lenses. The augmented reality (AR) and virtual reality (VR) glasses includes a pair of lenses retained by a frame. A lens stack is utilized in the pair of lenses. The lens stack may include multiple metasurfaces that improve the focus adjustment for both the real and virtual images as well as a prescription lens or prescription metasurface in the lens stack. The metasurfaces are coupled to a waveguide combiner to assist in overlaying virtual images on ambient environments. By utilizing a lens stack, the total weight of the glasses will decrease.