Device and method for compensating effects of pantoscopic tilt or wrap/sweep tilt on an image presented on an augmented reality or virtual reality display

Abstract

An optical device is disclosed for use in an augmented reality or virtual reality display, comprising a waveguide () and an input diffractive optical element (H; H) positioned in or on the waveguide, configured to receive light from a projector and couple it into the waveguide so that it is captured within the waveguide under total internal reflection. The input diffractive optical element has an input grating vector (G; G) in the plane of the waveguide. The device includes a first diffractive optical element (H; H) and a second diffractive optical element (H; H) having first and second grating vectors (G, G; GV, GV) respectively in the plane of the waveguide, wherein the first diffractive optical element is configured to receive light from the input diffractive optical element and to couple it towards the second diffractive optical element, and wherein the second diffractive optical element is configured to receive light from the first diffractive optical element and to couple it out of the waveguide towards a viewer. The input grating vector, the first grating vector and the second grating vector have different respective magnitudes, and wherein a vector addition of the input grating vector, the first grating vector and the second grating vector sums to zero.