Waveguide Combiner With Dynamic Grating Activation for Large Eyebox
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mixed reality displays face challenges in achieving a large eyebox size without reducing luminance or increasing power consumption, particularly in systems using pupil replication.
Innovation Solution
A waveguide combiner with dynamic grating activation, utilizing controllable diffraction gratings controlled by an eye tracking device to redirect light efficiently to the viewer's pupil, maintaining luminance and conserving power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If pupil replication is used to achieve a large eyebox size, then the viewing area increases, but luminance decreases and power consumption increases
Solution Approach 1:
The waveguide combiner is divided into multiple independently controllable diffraction grating regions, each corresponding to a specific pupil position. By segmenting the light redirection function across multiple spatially separated gratings, the system can activate only the necessary segments, concentrating light energy rather than dispersing it across the entire eyebox area, thus maintaining luminance while achieving large eyebox coverage.
Solution Approach 2:
The system dynamically activates or deactivates specific diffraction gratings based on real-time pupil position detection. This dynamic control allows the eyebox to adaptively expand to cover the required viewing area while maintaining high luminance by directing all available light to the active grating region, avoiding the luminance reduction that would occur with static full-eyebox illumination.
2Area of stationary object
If pupil replication is used to achieve a large eyebox size, then the viewing area increases, but power consumption increases
Solution Approach 1:
The waveguide combiner is divided into multiple independently controllable diffraction grating regions, each corresponding to a specific pupil position. By segmenting the light redirection function across multiple spatially separated gratings, the system can activate only the necessary segments, concentrating light energy rather than dispersing it across the entire eyebox area, thus maintaining luminance while achieving large eyebox coverage.
Solution Approach 2:
The system employs periodic or on-demand activation of diffraction gratings based on detected pupil position, rather than continuous activation of all gratings. This selective activation reduces power consumption by engaging only the specific grating regions needed for the current viewing condition, while still providing large eyebox coverage when required.
3Area of stationary object
If multiple diffraction gratings are activated simultaneously, then light is distributed across a larger area, but luminance at each point decreases
Solution Approach 1:
The waveguide combiner is divided into multiple independently controllable diffraction grating regions, each corresponding to a specific pupil position. By segmenting the light redirection function across multiple spatially separated gratings, the system can activate only the necessary segments, concentrating light energy rather than dispersing it across the entire eyebox area, thus maintaining luminance while achieving large eyebox coverage.
Solution Approach 2:
Different regions of the waveguide combiner are activated with different qualities or intensities based on local viewing requirements. The system applies high-intensity light redirection only to the locally relevant diffraction grating corresponding to the detected pupil position, rather than uniformly distributing light across all regions, thereby maintaining high luminance at the active location while still supporting a large overall eyebox.
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 system achieves a large eyebox with efficient light redirection, maintaining luminance and avoiding the need for increased power consumption by selectively activating diffraction gratings based on pupil position.
Implementation Method 1
a second optical element that is coupled to an output surface of the substrate and that outputs, from the waveguide combiner, the light propagated along the propagation path. This second optical element can be an out-coupling HOE that includes multiple diffraction gratings
Implementation Method 2
a substrate that is coupled to the first optical element and that propagates, along a propagation path within the substrate, the light received by the first optical element
Data Source
AI summary
A waveguide combiner with dynamic grating activation is described herein. In an example, an apparatus includes a first optical element that is configured to receive light. The apparatus also includes a substrate configured to propagate the light received by the first optical element along a propagation path within the substrate. The substrate includes an input surface and an output surface. The input surface is coupled to the first optical element. The apparatus also includes a second optical element coupled to the output surface and configured to output the light propagated along the propagation path. The second optical element includes a plurality of diffraction gratings at the output surface. Each one of the plurality of diffraction gratings has a corresponding controllable diffraction efficiency.