Eyepiece Waveguide UV Light Exit Grating
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Solution Overview
Problem
Current methods for fabricating waveguides for augmented and virtual reality systems face challenges in reducing the degradation caused by UV laser light used during the fabrication process, which affects the optical quality of the waveguides.
Innovation Solution
The use of waveguides with surface features, such as diffraction gratings or sloping surfaces, in the peripheral region to redirect and couple out UV light, reducing its impact on the main optical region and improving the waveguide's optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If UV laser light is used to cut waveguides from sheets of material, then waveguide fabrication is achieved, but UV light couples into the waveguide and degrades optical quality
Solution Approach 1:
The waveguide is divided into a main region and a peripheral region. The peripheral region contains surface features that specifically interact with UV light, while the main region maintains high optical quality for image propagation. This segmentation allows the UV-affected peripheral region to be isolated from the critical optical path.
Solution Approach 2:
The surface features in the peripheral region (such as diffraction gratings or sloping surfaces) convert the harmful UV light that couples into the waveguide during fabrication into a beneficial effect by redirecting it out of the waveguide. This prevents UV light from degrading the optical quality of the main region while allowing standard UV laser cutting processes to be used.
2Manufacturing precision
If surface features are added to redirect UV light, then optical quality is improved, but device complexity increases
Solution Approach 1:
Surface features are applied only to the peripheral region of the waveguide, not the entire structure. This localized approach provides the necessary UV light redirection functionality where it is most needed (at the edges where UV coupling occurs) while keeping the main optical region simple and free of additional structural 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
This approach effectively minimizes optical degradation by redirecting UV light out of the waveguide, thereby enhancing the optical quality and reducing haze and discoloration, leading to improved image presentation in AR and VR systems.
Implementation Method 1
said waveguide configured to propagate light from said at least one light source between said top and bottom major surfaces by total internal reflection
Implementation Method 2
a plurality of surface features within said peripheral region of said waveguide configured to couple light propagating in said waveguide out of said waveguide
Implementation Method 3
UV light that is employed to singulate the optical element or waveguide from a sheet of material
Data Source
AI summary
A method of forming a waveguide for an eyepiece for a display system to reduce optical degradation of the waveguide during segmentation is disclosed herein. The method includes providing a substrate having top and bottom major surfaces and a plurality of surface features, and using a laser beam to cut out a waveguide from said substrate by cutting along a path contacting and/or proximal to said plurality of surface features. The waveguide has edges formed by the laser beam and a main region and a peripheral region surrounding the main region. The peripheral region is surrounded by the edges.