Time-Multiplexed Grating Sets for Expanded Waveguide Field of View
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Solution Overview
Problem
Conventional waveguide display systems face limitations in expanding the field of view (FOV) without increasing the form factor, size of the light-generating display screen, or scanning range, which restricts the angular size of the output FOV to be equal to the input FOV, limiting the perceived image content and requiring larger components for increased FOV.
Innovation Solution
The implementation of a waveguide display system with multiple grating sets that couple input image lights into and out of the waveguide, where the output FOV is expanded by configuring the grating sets to operate in diffraction and non-diffraction states alternately, allowing for a combined output FOV larger than the input FOV without increasing the system's form factor or light-generating screen size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional waveguide display systems use a single grating set, then the system maintains a compact form factor, but the output field of view is limited to be equal to the input field of view
Solution Approach 1:
The patent divides the waveguide system into multiple grating sets (first grating set and second grating set) that operate at different time periods. Each grating set couples light into and out of the waveguide, but with different angular orientations. This segmentation allows the system to present different field of view orientations sequentially, achieving a combined expanded FOV while maintaining the compact waveguide form factor.
Solution Approach 2:
The patent implements periodic switching between different grating sets at different time periods. The first grating set operates during a first time period to provide light in a first orientation, while the second grating set operates during a second time period to provide light in a second orientation. This periodic action creates the perception of an expanded field of view by rapidly alternating between different angular outputs.
2Adaptability or versatility
If the system increases component size to expand field of view, then the output FOV increases, but the form factor and system size increase
Solution Approach 1:
The patent transitions from a static spatial arrangement to a temporal dimension by using multiple grating sets that operate at different time periods. Instead of requiring multiple large gratings to be present simultaneously (spatial arrangement), the system uses time-multiplexed gratings that alternate their operation. This dimensional change from space to time allows FOV expansion without increasing the physical footprint of the waveguide system.
Solution Approach 2:
The patent changes the operational parameters of the grating sets by controlling their diffraction states and switching between them at different time periods. The gratings are configured to diffract light at different angles during different time periods, effectively changing the angular parameter of light output over time. This parameter change in the temporal domain achieves FOV expansion without requiring larger physical components.
3Adaptability or versatility
If multiple grating sets are used to expand FOV, then the output FOV increases, but the device complexity increases
Solution Approach 1:
The patent designs multiple grating sets that can serve universal functions within the waveguide system. Each grating set is capable of coupling light into and out of the waveguide, and they can be controlled to operate in different diffraction states. This multi-functionality allows the same type of component (grating set) to serve different angular output requirements, reducing the need for entirely different component types and simplifying the overall system architecture.
Solution Approach 2:
The patent introduces dynamic control of the grating sets by switching between their diffraction states at different time periods. The gratings are not static but are dynamically activated and deactivated based on the desired output orientation. This dynamic operation allows a single physical grating structure to effectively perform multiple functions by changing its operational state, thereby reducing the need for permanently installed multiple complex components.
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 solution effectively increases the output FOV by up to twice the input FOV, enhancing the perceived image content without increasing the system's size or weight, maintaining a compact form factor and reducing costs.
Implementation Method 1
A waveguide display system with diffractive coupling structures... The diffractive coupling structures functioning as an out-coupling element replicate the virtual image at the output side of the waveguide to expand an effective pupil
Implementation Method 2
a waveguide coupled with diffractive coupling structures to guide the image light to an eye-box of the waveguide display system
Data Source
AI summary
A device includes a waveguide. The device also includes a plurality of grating sets coupled with the waveguide and configured to, during a plurality of time periods, couple a plurality of input image lights into and out of the waveguide as a plurality of output image lights. In a first grating set of the plurality of grating sets, a first vector sum of in-plane projections of grating vectors associated with all gratings included in the first grating set is a first non-null vector. In a second grating set of the plurality of grating sets, a second vector sum of in-plane projections of grating vectors associated with all gratings included in the second grating set is a second non-null vector. The first vector sum and the second vector sum have different directions.