US20250110331
2025-04-03
Physics
G02B27/0093
The patent application details a lens assembly designed for Augmented Reality (AR) glasses. It comprises a waveguide substrate, a wiring layer, a protective layer, an eye tracking component, and a lens. The waveguide substrate is the base, with the wiring layer placed on its first surface. A protective layer covers this wiring layer, while the eye tracking component is embedded within the protective layer and is electrically connected to the wiring layer. The lens is attached to the side of the protective layer opposite the waveguide substrate. The AR glasses feature a display device situated between two such lens assemblies to project images onto the waveguide substrates.
Traditional AR glasses lenses include a wiring layer with eye-tracking capabilities sandwiched between a waveguide substrate and lenses. An auxiliary structure often exists between the waveguide substrate and wiring layer, typically made from resin like polyimide, which protects and prevents debonding but increases thickness. The current design aims to streamline this by eliminating unnecessary layers to achieve a thinner lens assembly without compromising functionality.
The application describes several embodiments of the lens assembly. Key components include a waveguide substrate with first and second surfaces, which can be planar or curved based on design needs. A grating structure within the waveguide substrate allows light refraction and directionality. The wiring layer is directly molded onto the substrate's first surface, simplifying manufacturing and reducing thickness. The protective layer covers this setup, housing an eye-tracking component that connects electrically to the wiring layer.
The waveguide substrate is primarily composed of plastic materials like polyethylene terephthalate (PET) or polymethyl methacrylate (PMMA), offering advantages in weight, cost, and durability over glass substrates. These materials facilitate easier processing and reduce risks of damage or debonding. Additionally, a transmittance-enhancing layer may be included to improve light transmission efficiency through Bragg reflection structures.
The eye-tracking system includes conductive wires and pads made from materials like copper or silver. These components are crucial for electrical connectivity within the lens assembly. The eye-tracking component itself consists of a light-emitting member, such as an LED or laser, directed at the eye, and a receiving member like a photosensitive element or camera. This system tracks eye movement by analyzing reflected light rays from the eye.