Holographic waveguide HUD with in-line pupil expansion and 2D FOV expansion

A method of head-up display is presented that uses an in-line surface relief grating attached to a waveguide propagation head-up display to achieve a large field of view without the need for large-projection optics. Horizontal pupil expansion is achieved using an extraction hologram that is multiple times the size of the injection hologram and is recorded with modulated diffraction efficiency. Vertical pupil expansion is achieved by coupling the surface relief grating to the waveguide surface between the injection and extraction holograms. The grating replicates the beam along the propagation direction, which allows for a larger field of view at the extraction. Using this technique, both a Zemax OpticStudio computer model and a physical system demonstrator achieve a field of view of 16∘×14.25∘.