Separate-Substrate Waveguide with EPE and Outcoupler for FOV Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional eyewear displays have a limited field of view (FOV) due to interference between the exit pupil expander (EPE) and outcoupler components within the waveguide substrate, making it impractical to enlarge them without reducing available space.
Innovation Solution
The EPE and outcoupler are positioned on separate substrates with a partition element and reflective facets to direct light between them, maintaining total internal reflection (TIR) conditions and preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the EPE and outcoupler are placed on the same waveguide substrate, then the device complexity is reduced, but the field of view area is limited due to component interference
Solution Approach 1:
The waveguide is divided into multiple separate substrates, with the EPE on a first substrate and the outcoupler on a second substrate. This segmentation allows each component to be optimized independently without interfering with the other, thereby expanding the field of view area while managing device complexity through modular architecture
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement of components on a single substrate to a three-dimensional stacked configuration with multiple substrates positioned at different heights. The partition element creates vertical separation, allowing the EPE and outcoupler to coexist without spatial interference, thus expanding the achievable field of view area
2Area of stationary object
If the EPE and outcoupler are enlarged to expand FOV, then the field of view area increases, but the available space within the waveguide substrate is reduced
Solution Approach 1:
By moving from a single-substrate two-dimensional layout to a multi-substrate three-dimensional stack, the patent utilizes the vertical dimension to accommodate larger EPE and outcoupler components. The partition element provides vertical separation, allowing each component to be enlarged without compromising the other's functionality or reducing available space
3Area of stationary object
If separate substrates are used for EPE and outcoupler, then the field of view area expands, but the device complexity increases
Solution Approach 1:
The waveguide is divided into multiple separate substrates, with the EPE on a first substrate and the outcoupler on a second substrate. This segmentation allows each component to be optimized independently without interfering with the other, thereby expanding the field of view area while managing device complexity through modular architecture
Solution Approach 2:
A partition element is introduced as an intermediary component between the first substrate containing the EPE and the second substrate containing the outcoupler. This partition element manages the optical interface between substrates, maintaining total internal reflection conditions while enabling the expanded field of view configuration
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 allows for the expansion of the FOV area without interfering with the EPE and outcoupler, enabling larger image display regions within the eyewear display.
Implementation Method 1
the waveguide includes one or more facets to direct light from the first substrate to the second substrate
Implementation Method 2
the partition element comprises a lower-refractive index than the first substrate and the second substrate
Implementation Method 3
the one or more facets comprise reflective facets comprising a mirror coating
Data Source
AI summary
A waveguide includes a first substrate including an exit pupil expander and a second, separate substrate including an outcoupler. The first substrate and the second substrate overlap one another and are separated by a partition element. One or more facets direct light from the first substrate after exit pupil expansion toward the second substrate so that the light can be outcoupled by the outcoupler.