Diffractive Optical Waveguide With Elliptical Turning Holes for Brighter AR
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Solution Overview
Problem
The existing diffractive optical waveguides in augmented reality display technology suffer from reduced light utilization rates due to multiple diffraction gratings, leading to diminished brightness and user experience, especially in outdoor use.
Innovation Solution
Incorporating a diffractive optical waveguide with a turning region featuring elliptical through holes and reducing the number of gratings, allowing light to propagate efficiently through the waveguide substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple diffraction gratings are used in the waveguide lens (in-coupling, turning, and out-coupling regions), then optical image transmission is achieved, but light energy is significantly dissipated during total reflection, reducing emitted light utilization rate and display brightness
Solution Approach 1:
The patent extracts the turning function from the traditional grating structure and replaces it with a dedicated turning region that uses total internal reflection. This separates the diffraction function (performed by in-coupling and out-coupling gratings) from the turning function, eliminating the need for multiple gratings and reducing light energy dissipation while maintaining optical image transmission capability
Solution Approach 2:
The patent applies different optical mechanisms to different regions: the in-coupling region uses diffraction gratings for light coupling, the turning region uses total internal reflection for light direction change, and the out-coupling region uses diffraction gratings for light output. This localized optimization ensures each region performs its function with minimal energy loss, improving overall light utilization rate and brightness
2Ease of operation
If multiple diffraction gratings are used in the waveguide lens, then optical coupling and image transmission are achieved, but the quantity of gratings increases device complexity and reduces light utilization rate
Solution Approach 1:
The patent extracts the turning function from the grating system and creates a dedicated turning region. This reduces the number of gratings from three (in-coupling, turning, out-coupling) to two (in-coupling, out-coupling), simplifying device structure while maintaining optical coupling functionality through the combination of diffraction gratings and total internal reflection
Solution Approach 2:
The turning region serves multiple functions: it changes light direction, maintains light energy through total internal reflection, and eliminates the need for a separate turning grating. This multi-functional design reduces device complexity while preserving optical coupling capability
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 design enhances light brightness incident to the human eye by preventing energy dissipation during total reflection, thereby improving user experience.
Implementation Method 1
The diffractive optical waveguide lens mainly uses flat glass as a transmission body of a waveguide and has a grating waveguide structure of in-coupling, turning, and out-coupling
Implementation Method 2
Energy of the light becomes increasingly weaker during total reflection in an optical waveguide
Data Source
AI summary
This application provides a diffractive optical waveguide, augmented reality glasses, and an augmented reality display device. The diffractive optical waveguide includes: a waveguide substrate and a plurality of functional regions located on a surface of the waveguide substrate. The functional regions include an in-coupling grating region, a turning region, and an out-coupling grating region. The turning region is arranged in parallel with the in-coupling grating region along a first direction. The out-coupling grating region is arranged in parallel with the turning region along a second direction. The first direction and second direction are perpendicular to each other. The turning region is provided with a plurality of elliptical through holes. The elliptical through holes are arranged at intervals and distributed in the turning region and penetrate from a top surface of the waveguide substrate to a bottom surface of the waveguide substrate.