Waveguide Diffraction Gratings for AR Optical Loss Reduction
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Solution Overview
Problem
Optical loss occurs during the transmission of light to a user's retina via optical elements in augmented reality systems, necessitating the development of more efficient light delivery methods.
Innovation Solution
An optical device featuring a waveguide with a first and second diffraction grating, where the second diffraction grating diffracts light in three-dimensional directions, utilizing a pattern based on grating vectors corresponding to the sides of a polyhedron inscribed in a sphere, to reduce optical loss and enhance light output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light is transmitted through optical elements in augmented reality systems, then virtual images can be displayed to users, but optical loss occurs during transmission
Solution Approach 1:
The patent applies diffraction gratings that operate in three-dimensional space to redirect light from the waveguide to the user's retina. The first and second diffraction gratings work together to expand and redirect light in multiple dimensions, improving light delivery efficiency and reducing optical loss compared to conventional one-dimensional optical elements.
Solution Approach 2:
The diffraction gratings serve as intermediary optical elements between the waveguide and the user's retina. These gratings mediate the light transmission process by efficiently coupling light from the waveguide output to the user's eye, thereby reducing optical loss and improving overall transmission efficiency.
2Loss of energy
If conventional optical elements are used to deliver light to the user's retina, then the system structure is simple, but optical loss increases
Solution Approach 1:
The patent divides the light delivery function into separate stages using a first diffraction grating and a second diffraction grating. The first grating handles initial light expansion and the second grating handles final direction control, segmenting the optical path to improve efficiency while keeping each individual element relatively simple.
Solution Approach 2:
By introducing diffraction gratings that operate in three-dimensional space rather than conventional planar optical elements, the patent achieves more efficient light delivery. The gratings create three-dimensional light patterns that better match the user's retinal geometry, reducing optical loss despite the increased dimensional 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 solution effectively reduces optical loss and increases light-output efficiency by diffracting light in three-dimensional directions, allowing for more efficient perception of virtual images in augmented reality systems.
Implementation Method 1
a first diffraction grating receiving at least a portion of light incident on the waveguide
Implementation Method 2
a second diffraction grating receiving a light diffracted from the first diffraction grating, wherein the light diffracted from the second diffraction grating is diffracted in three-dimensional directions
Data Source
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AI summary
Provided are an optical device and a method of outputting light using the optical device. The optical device includes a waveguide, a first diffraction grating receiving at least a portion of light incident on the waveguide and a second diffraction grating receiving a light diffracted from the first diffraction grating,, wherein the first diffraction grating and the second diffraction grating are provided in or on the waveguide, the light diffracted from the first diffraction grating is diffracted, in three-dimensional directions, from the second diffraction grating, and at least a portion of the light diffracted in the three-dimensional directions is output to an outside of the waveguide.