AR Waveguide Diffractive Element Architecture for Wide Field of View
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Solution Overview
Problem
Existing augmented reality glasses face challenges in achieving a wide field of view while maintaining a compact, lightweight, and cost-effective design, as increasing the number of waveguides or diffractive optical elements leads to increased thickness, weight, and production complexity, and can result in image quality issues such as ghosting and loss of chromaticity.
Innovation Solution
A waveguide with a diffractive optical elements-based architecture that includes a light in-coupling zone, a light expanding zone, and a light out-coupling zone, utilizing a configuration where each diffractive optical element performs multiple functions, such as in-coupling, expanding, and out-coupling, to reduce the number of elements required and improve image quality, while ensuring a wide field of view and full-color imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the number of waveguides is increased to achieve a wide field of view, then the field of view is improved, but the device dimensions and weight increase
Solution Approach 1:
Each diffractive optical element is designed to perform multiple functions simultaneously: in-coupling light into the waveguide, expanding the light beam, and out-coupling light to the user's eye. This multi-functionality reduces the total number of elements needed, thereby decreasing device weight while maintaining a wide field of view of more than 80 degrees diagonal
Solution Approach 2:
The patent combines three separate diffractive optical elements (in-coupling, expanding, and out-coupling) into a single integrated element with multiple zones. This merging approach reduces the number of components, simplifies the waveguide architecture, and decreases overall device weight while achieving the desired wide field of view
2Duration of action of moving object
If the number of diffractive optical elements is increased to achieve a wide field of view, then the field of view is improved, but the device complexity and production difficulty increase
Solution Approach 1:
The diffractive optical element is designed as a universal component that performs in-coupling, expanding, and out-coupling functions within a single element. This reduces device complexity by eliminating the need to manage multiple separate elements and their associated alignment requirements
Solution Approach 2:
The single diffractive optical element is segmented into multiple functional zones (in-coupling zone, expanding zone, out-coupling zone) that work together to achieve the wide field of view. This segmentation allows complex functionality to be achieved within a single element rather than requiring multiple separate elements
3Duration of action of moving object
If multiple diffractive optical elements are used, then the field of view is improved, but image quality deteriorates due to ghosting and loss of chromaticity
Solution Approach 1:
The design extracts and eliminates the problematic double diffraction effect by using a single diffractive optical element instead of multiple elements. This removes the source of ghost images and chromaticity loss while maintaining the wide field of view through the element's multiple functional zones
Solution Approach 2:
The universal diffractive optical element performs all necessary functions (in-coupling, expanding, out-coupling) in a coordinated manner within a single component, ensuring proper light path management and preventing the image quality issues that arise from multiple separate elements
4Duration of action of moving object
If the number of waveguides is increased to achieve a wide field of view, then the field of view is improved, but the device thickness increases
Solution Approach 1:
Multiple waveguide functions are merged into a single waveguide by using one diffractive optical element that performs in-coupling, expanding, and out-coupling. This consolidation maintains a thin waveguide structure while achieving a wide field of view through the coordinated action of the element's multiple zones
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 achieves a diagonal field of view of more than 80°, eliminates ghost images by avoiding double diffraction, and enhances image quality with increased brightness and resolution, while maintaining a compact and lightweight design.
Implementation Method 1
When the image interacts with an in-coupling diffraction grating, part of the image is cut off, since only the image part, which can exist only in the aforementioned range of angles, remains
Implementation Method 2
Inner boundary of the ring is the area of the angle of total internal reflection (TIR), i.e., in this case there is a critical angle at which the light propagates without leaving the waveguide
Implementation Method 3
when interacting with an expanding diffraction element, the vector of which is marked in FIG. 1 as Kexp, part of the angles is also cut off from the image by the same borders, but vertically
Data Source
AI summary
The disclosure relates to augmented reality devices and methods for operating such devices. A waveguide with a diffractive optical elements-based architecture for an augmented reality device is provided. The waveguide includes a light in-coupling zone, a light expanding zone, and a light out-coupling zone. Each zone includes its own set of diffractive optical elements performing the light in-couple, light expand and light out-couple function. There are further provided an augmented reality display device and augmented reality glasses based on the waveguide with the diffractive optical elements-based architecture.