Abstract: There is disclosed a waveguide for use in an augmented reality or virtual reality display. The waveguide comprises a plurality of optical structures in a photonic crystal. The plurality of optical structures are arranged in an array to provide at least two diffractive optical elements. Each of the two diffractive optical elements is configured to receive light from an input direction and couple it towards the other diffractive optical element which can then act as an output diffractive optical element, providing outcoupled orders towards a viewer. The plurality of optical structures respectively have a shape, when viewed in the plane of the waveguide, comprising twelve substantially straight sides, six of the sides having respective normal vectors at a first angle, and the other six of the sides having respective normal vectors at a second angle which is different to the first angle.

Abstract: An optical device for controlling light in an augmented reality display is provided. The optical device includes a waveguide and a diffractive optical element to couple light into the waveguide. The diffractive optical element includes an array of structured grating elements. The structured grating elements are arranged based on a repeating unit cell, each unit cell including at least two grating elements defining an irregular grating structure such that the diffractive optical element produces an asymmetrical diffraction response. Methods of manufacturing the optical device are also provided.

Abstract: An augmented reality device is provided and comprises a waveguide (306); an input diffractive optical element (301) positioned in or on the waveguide (306) configured to receive light from a projector and to couple the light into the waveguide (306) so that it is captured within the waveguide (306) by total internal reflection; an output diffractive optical element (304) positioned in or on the waveguide (306) configured to couple totally internally reflected light out of the waveguide (306) towards a viewer; and a returning diffractive optical element (307, 309, 312) positioned in or on the waveguide (306) configured to receive light from the output diffractive optical element (304) and to diffract the received light so that it is returned towards the output diffractive optical element (304).

Abstract: There is disclosed a waveguide for use in an augmented reality or virtual reality display. The waveguide comprises a plurality of optical structures in a photonic crystal. The plurality of optical structures are arranged in an array to provide at least two diffractive optical elements. Each of the two diffractive optical elements is configured to receive light from an input direction and couple it towards the other diffractive optical element which can then act as an output diffractive optical element, providing outcoupled orders towards a viewer. The plurality of optical structures respectively have a shape, when viewed in the plane of the waveguide, comprising twelve substantially straight sides, six of the sides having respective normal vectors at a first angle, and the other six of the sides having respective normal vectors at a second angle which is different to the first angle.