Diffractive Waveguide Optics for Compact Multi-Depth AR Displays
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Solution Overview
Problem
Existing augmented reality (AR) technologies face challenges in providing a comfortable and natural-feeling presentation of virtual image elements amidst real-world imagery due to the complexity of the human visual system, and there is a demand to reduce the size of display systems, including components like polarizing beam splitters.
Innovation Solution
A head-mounted display system with a frame, image projector, waveguide, coupling and out-coupling elements, and a camera is designed to project and capture light, enabling realistic three-dimensional imagery by simulating multiple depth planes using a stack of waveguides with varying levels of wavefront curvature and divergence, and incorporating optical elements like diffractive optical elements (DOEs) for efficient light redirection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarizing beam splitters are used to direct polarized light to light modulators, then light can be effectively directed to the viewer, but the size of the display system increases
Solution Approach 1:
The patent combines the beam splitter function with the waveguide structure by integrating diffractive optical elements directly into the waveguide. This merging eliminates the need for separate polarizing beam splitters while maintaining the light direction control function, thereby reducing the overall display system size.
Solution Approach 2:
The patent replaces mechanical polarizing beam splitters with diffractive optical elements that utilize light diffraction and waveguide total internal reflection. This substitution eliminates the need for mechanical polarizing components while achieving the same light direction control function with a more compact design.
2Ease of manufacture
If multiple depth planes are simulated using waveguides with varying wavefront curvature, then realistic three-dimensional imagery is achieved, but device complexity increases
Solution Approach 1:
The patent divides the display system into multiple waveguide layers, with each waveguide responsible for a specific depth plane. This segmentation allows each waveguide to be independently designed and manufactured with specific wavefront curvature properties, simplifying the overall manufacturing process while achieving realistic three-dimensional imagery.
Solution Approach 2:
The patent varies the wavefront curvature parameter across different waveguide layers to simulate different depth planes. By changing this physical parameter rather than adding complex mechanical structures, the system achieves three-dimensional imagery quality while controlling device complexity.
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 provides a more realistic and comfortable AR experience by accurately simulating depth perception through multiple depth planes, enhancing user comfort and reducing system size by optimizing the use of waveguides and optical elements.
Implementation Method 1
at least one out-coupling element configured to couple light that is guided within the waveguide out of the waveguide and direct the light to the camera
Implementation Method 2
at least one waveguide configured to propagate light therein
Data Source
AI summary
A head mounted display system can include a camera, at least one waveguide, at least one coupling optical element that is configured such that light is coupled into said waveguide and guided therein, and at least one out-coupling element. The at least one out-coupling element can be configured to couple light that is guided within said waveguide out of said waveguide and direct said light to said camera. The at least one coupling element may comprise a diffractive optical element having optical power.