Fold-Grating Waveguide Structure for Large AR Field of View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing augmented reality waveguides face challenges in achieving a large field-of-view for effectively overlaying virtual images on the ambient environment.
Innovation Solution
The waveguide incorporates an incoupler grating with blazed structures and a metal material over a substrate, along with intermediate and outcoupler gratings featuring variable depth and binary or angled structures, formed using a litho-etch process, to enhance the field-of-view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional waveguide structures are used, then the device complexity is low, but the field-of-view is limited
Solution Approach 1:
The waveguide is divided into multiple functional sections with different grating structures: an incoupler grating with blazed structures for light entry, intermediate gratings for wave propagation control, and an outcoupler grating for light exit. Each section is optimized independently to contribute to the overall large field-of-view while managing complexity through functional segmentation.
Solution Approach 2:
Different regions of the waveguide are assigned different grating structures tailored to their specific functions. The incoupler region uses blazed structures with specific slant angles for efficient light coupling, while intermediate and outcoupler regions use variable depth structures optimized for their respective positions, allowing each local area to contribute optimally to the overall field-of-view performance.
2Use of energy by moving object
If blazed structures with slant angle are used in the incoupler grating, then light coupling efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The blazed structures are defined by specific slant angle parameters that are optimized for light coupling efficiency. By precisely controlling the slant angle parameter during fabrication, the design achieves high coupling efficiency while the parameter-based definition simplifies the manufacturing process compared to more complex geometric variations.
Solution Approach 2:
The incoupler grating combines blazed structures with a metal material layer, creating a composite structure that enhances light coupling efficiency through the synergistic effects of the blazed geometry and metal optical properties, while the composite nature allows for optimized fabrication processes.
3Area of stationary object
If variable depth device structures are used in intermediate and outcoupler gratings, then field-of-view is expanded, but manufacturing precision requirements increase
Solution Approach 1:
The variable depth of the device structures is defined by specific depth parameters that are optimized to expand the field-of-view. By controlling the depth parameter as a primary design variable rather than complex geometric features, the manufacturing precision requirements are managed while achieving the desired optical performance expansion.
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 enables a field-of-view larger than 40 degrees, providing high efficiency and good color uniformity for world-locked mixed reality applications.
Implementation Method 1
The incoupler (IC) grating includes a plurality of blazed structures disposed over a substrate. The plurality of blazed structures having a blazed surface with a slant angle relative to a plane parallel to the substrate.
Implementation Method 2
Generated light is in-coupled into a waveguide, propagated through the augmented waveguide, out-coupled from the augmented waveguide
Implementation Method 3
A metal material disposed over the plurality of blazed structures
Implementation Method 4
An intermediate grating and an outcoupler (OC) grating each including a plurality of device structures. The plurality of device structures having a variable depth.
Data Source
AI summary
Embodiments of the present disclosure generally relate to augmented reality waveguides for augmented, virtual, and mixed reality. More specifically, embodiments described herein provide waveguides with a large field-of-view and a method of forming the same. In one embodiment, a waveguide is provided. The waveguide includes an incoupler (IC) grating. The incoupler (IC) grating includes a plurality of blazed structures disposed over a substrate. The plurality of blazed structures having a blazed surface with a slant angle relative to a plane parallel to the substrate. The waveguide further includes a metal material disposed over the plurality of blazed structures. An intermediate grating and an outcoupler (OC) grating each including a plurality of device structures. The plurality of device structures having a variable depth.