Single-Sided Grating Coupler Eyepiece for Wider Field of View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical eyepieces fabricated using imprint lithography have a limited field of view and increased fabrication complexity due to double-sided lithography, which worsens coherent artifacts and decreases manufacturing yield and throughput.
Innovation Solution
An optical eyepiece design utilizing single-sided patterning of grating couplers, including an in-coupling grating and multiple grating couplers on a single side of the substrate, with different grating patterns to diffract and combine light efficiently, reducing the need for long-distance travel and minimizing coherent artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If double-sided lithography is used to manufacture eyepieces, then the field of view can be improved, but the fabrication complexity increases and manufacturing yield decreases
Solution Approach 1:
The patent extracts the grating structures from one side of the substrate and places them all on the other side. Specifically, the in-coupling grating and multiple grating couplers are patterned on a single side of the substrate, eliminating the need for double-sided lithography while maintaining the optical functionality that requires multiple grating interactions
Solution Approach 2:
The patent utilizes the third dimension (substrate thickness) by positioning the in-coupling grating and grating couplers at different depths within the substrate. This vertical stacking allows multiple grating interactions to occur on a single side plane, effectively achieving the optical path complexity of double-sided lithography through single-sided patterning with vertical separation
2Area of stationary object
If light travels a long distance to reach the exit pupil expander, then the field of view can be expanded, but coherent artifacts are worsened
Solution Approach 1:
The patent segments the light propagation path into multiple short stages by introducing intermediate grating couplers between the in-coupling grating and the exit pupil expander. Instead of one long direct path, light undergoes sequential diffraction and guidance through multiple closely-spaced grating elements, reducing the cumulative coherent artifacts while achieving the same field of view expansion
Solution Approach 2:
The patent introduces intermediate grating couplers as mediator elements between the in-coupling grating and the exit pupil expander. These intermediate gratings act as stepping stones that break up the long direct light path into shorter segments, reducing coherent artifacts while maintaining the overall field of view expansion function
3Reliability
If double-sided lithography is used, then the optical path can be optimized, but manufacturing throughput decreases
Solution Approach 1:
The patent extracts all grating structures from one side of the substrate and consolidates them on the opposite side. This single-sided patterning approach eliminates the need for substrate flipping and second lithography processing, thereby optimizing manufacturing throughput while maintaining optical path functionality through vertical stacking and intermediate gratings
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
The design enhances the field of view, efficiency, and uniformity of optical eyepieces for virtual and augmented reality applications, while reducing fabrication complexity and increasing manufacturing yield and throughput.
Implementation Method 1
The in-coupling grating is configured to diffract light received from a projector into a first portion of the light and a second portion of the light. The first portion has a first orientation with respect to the light received from the projector. The second portion has a second orientation with respect to the light received from the projector.
Implementation Method 2
A first grating coupler is patterned on the single side of the substrate. The first grating coupler has a first grating pattern. The first grating coupler is optically coupled to the in-coupling grating. A second grating coupler is patterned on the single side of the substrate adjacent to the first grating coupler. The second grating coupler has a second grating pattern different from the first grating pattern.
Data Source
AI summary
An eyepiece includes a substrate and an in-coupling grating patterned on a single side of the substrate. A first grating coupler is patterned on the single side of the substrate and has a first grating pattern. The first grating coupler is optically coupled to the in-coupling grating. A second grating coupler is patterned on the single side of the substrate adjacent to the first grating coupler. The second grating coupler has a second grating pattern different from the first grating pattern. The second grating coupler is optically coupled to the in-coupling grating.