Waveguide Light Pipe Coupling for Compact AR Displays
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Solution Overview
Problem
Current waveguide optics require multiple layers for dual axis expansion, leading to increased thickness, weight, and haze, making them unsuitable for compact display and sensor applications, particularly in Augmented Reality, Virtual Reality, and LIDAR, where a low-cost, efficient means for first axis expansion is needed.
Innovation Solution
A waveguide apparatus comprising a light pipe with a light coupling element and an optical waveguide, where the light coupling element can be a grating, beam splitter, or evanescent coupling medium, allowing for efficient transmission and reception of light, and featuring abutting elongate elements inclined at a common angle for optimal beam expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple layers are used for dual axis expansion in waveguide optics, then beam expansion capability is improved, but device thickness and weight increase
Solution Approach 1:
The patent combines multiple grating layers into a single integrated waveguide structure, merging the functions of separate expansion layers into one unified component. This integration maintains dual-axis beam expansion capability while eliminating the cumulative thickness and weight of multiple discrete layers.
Solution Approach 2:
The invention utilizes the third dimension (depth/thickness) of a single waveguide layer to achieve expansion in two orthogonal directions (x and y axes). By encoding grating patterns that operate in multiple dimensions within one layer, the system achieves dual-axis expansion without requiring physically stacked layers.
2Adaptability or versatility
If multiple layers are used for dual axis expansion, then beam expansion capability is improved, but device complexity increases
Solution Approach 1:
Multiple functional grating layers are merged into a single waveguide layer with integrated patterning. The design combines first-axis and second-axis expansion gratings into one structure, reducing the number of discrete components and simplifying the overall device architecture.
Solution Approach 2:
A single waveguide layer performs multiple functions: it provides both first-axis and second-axis beam expansion, acts as the optical guiding medium, and integrates the diffractive elements. This multi-functional design eliminates the need for separate specialized layers for each function.
3Adaptability or versatility
If multiple layers are used for dual axis expansion, then beam expansion capability is improved, but haze increases
Solution Approach 1:
By merging multiple grating functions into a single layer, the patent eliminates the interfaces between layers that would otherwise scatter light and create haze. The unified structure reduces optical disruptions while maintaining the beam expansion functionality of what would have been multiple separate layers.
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 enables efficient first axis expansion in dual axis expansion waveguides, reducing the number of layers required and minimizing thickness and weight, while maintaining high transparency and diffraction efficiency, suitable for both display and sensor applications.
Implementation Method 1
The light coupling element can be a grating
Implementation Method 2
The light coupling element can be an evanescent coupling medium
Implementation Method 3
a light pipe with an optical axis for guiding light therethrough
Data Source
AI summary
A waveguide apparatus comprises in combination: a light pipe with an optical axis for guiding light therethrough; a light coupling element in optical contact with an elongate portion of the reflecting surface of the light guide; and an optical waveguide in optical contact with the coupling element.