Waveguide for head-up display, including reflective output coupling structure
AssigneeBAE SYSTEMS plc
InventorsJAMES RAYMOND LEIGHTON, MICHAEL DAVID SIMMONDS, RORY THOMAS ALEXANDER MILLS
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Abstract
A waveguide structure for a head up display in which a reflective output coupling structure is formed of a separate, but connected, component to a main waveguide. Light is coupled from the main waveguide to the output coupling structure by evanescent wave coupling. In a method of manufacture for such a waveguide the output coupling structure is attached to the main waveguide using an optical feedback technique.
Claims20
An optical waveguide for a head up display, the waveguide comprising:
- a waveguide body extending from an input end to an output end and configured to guide light by total internal reflection from the input end to the output end;
- an input coupling device at the input end of the waveguide body for coupling light into the waveguide body;
- and
- an output coupling structure attached to a face of the waveguide body at the output end with an air gap between a region of the output coupling structure and the face of the waveguide body, the air gap being such that light is coupled from the region to the output coupling structure by evanescent wave coupling, wherein the output coupling structure is a reflective structure configured to direct light out of the optical waveguide by reflection.
A method of manufacturing a waveguide for a head up display, the method comprising:
- providing a waveguide body having an input end and an output end;
- and
- attaching a reflective output coupling structure to a face of the waveguide body with an air gap between a region of the output coupling structure and the face of the waveguide body, the air gap being such that light is coupled from the waveguide body to the output coupling structure by evanescent wave coupling.
An optical waveguide for a head up display, the waveguide comprising:
- a waveguide body extending from an input end to an output end and configured to guide light by total internal reflection from the input end to the output end;
- an input coupling device at the input end of the waveguide body for coupling light into the waveguide body, wherein the input coupling device includes a prism or a diffractive grating;
- and
- an output coupling structure attached to a face of the waveguide body at the output end with an air gap between a region of the output coupling structure and the face of the waveguide body, the air gap being such that light is coupled from the region to the output coupling structure by evanescent wave coupling, wherein the output coupling structure includes a saw-tooth grating configured to reflect light out of the optical waveguide.
Dependencies are inferred from the claim text.