Abstract: A waveguide has an output diffractive optical element to couple light out of the waveguide towards a viewer, and a returning diffractive optical element to receive light from the output diffractive optical element and return the received light toward the output diffractive optical element. The output diffractive optical element has overlaid first and second output diffractive optical elements. The first output diffractive optical element receives light from an input direction and couples it toward the second output diffractive optical element in a first direction that is oblique to the input direction. The second output diffractive optical element receives light from the input direction and couples it towards the first output diffractive optical element in a second direction that is oblique to the input direction. The returning diffractive optical element has first and second returning diffractive optical elements that return light opposite the first and second directions, respectively.

Abstract: An optical structure is disclosed for use in an augmented reality display. The structure includes a waveguide (52) and an input diffractive optical structure (54) configured to receive light from a projector and couple the received light into the waveguide (52). An output diffractive optical structure (60) is configured to receive light from the input diffractive optical element (54) in an input direction, wherein the output diffractive optical structure comprises at least a first diffractive optical element (30) and a second diffractive optical element (32) with different respective diffraction efficiencies, wherein the first diffractive optical element has a relatively high diffraction efficiency and the second diffractive optical element has a relatively low diffraction efficiency and the first and second diffractive optical elements are overlaid on one another in or on the waveguide. The output diffractive optical structure (60) comprises a first portion (62) and a second portion (64).

Abstract: An optical structure for an augmented reality display includes a waveguide and an input diffractive optical structure to receive light from a projector and couple the received light into the waveguide. An output diffractive optical structure, comprising first and second diffractive optical elements overlaid on one another in or on the waveguide, receives light from the input diffractive optical element in an input direction. The first diffractive optical element has a high diffraction efficiency relative to the second diffractive optical element. A first portion of the first diffractive optical element couples light from the input direction towards a second portion, and the second diffractive optical element couples light from the input direction away from the second portion. The second portion couples light from the input direction towards the first portion, and the second diffractive optical element couples light from the input direction away from the first portion.

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 AR or VR display device. First and third input gratings receive light of a first color from first and second projectors, respectively, coupling the light into a first waveguide. Second and fourth input gratings receive light of a second color from the first and second projectors, respectively, coupling the light into a second waveguide. An output diffractive optical element couples light out of the waveguides towards a viewing position. The first and second projectors provide light to the input diffractive optical elements in directions that are at a first and second angle, respectively, to a waveguide normal vector. The output diffractive optical element couples light out of the waveguides in a first range of angles for light from the first projector and in a second range of angles for light from the second projector, the first range of angles and the second range of angles differing but partially overlapping.

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 is disclosed for use in an augmented reality or virtual reality display, comprising a waveguide (12; 22; 32) and an input diffractive optical element (H0; H3; 34) 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 (G0; Gig) in the plane of the waveguide.

Abstract: An augmented reality or virtual reality display device is disclosed. A first input grating (6; 106; 306; 406; 506) is provided on a waveguide assembly to receive light from a first projector (2; 102; 202; 302; 402; 502) and to couple the light into the at least one waveguide. A second input grating (116; 316; 416; 516) is provided to receive light from a second projector (12; 112; 212; 312; 412; 512) and couple the light into the at least one waveguide. An output diffractive optical element couples light out of the at least one waveguide towards a notional viewing position. The first projector provides light to the first input diffractive optical element in a direction that is at a first angle to a waveguide normal vector, and the second projector is configured to provide light to the second input diffractive optical element in a direction that is at a second angle to the waveguide normal vector.

Abstract: A waveguide for use in an augmented reality or virtual reality display comprises a plurality of optical structures in or on a photonic crystal. The plurality of optical structures are arranged in an array to provide two diffractive optical elements overlaid on one another in the waveguide. 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 have different respective cross sectional shapes, for a cross section parallel to the plane of the waveguide, at different positions in the array in order to provide different diffraction efficiencies at different positions in the array.

Abstract: An augmented reality display is disclosed. A colour projector 2 emits an image in a narrow beam comprising three primary colours: red, green and blue. A pair of waveguides 4, 6 is provided in the path of the projected beam. A first input grating 8 receives light from the projector 2 and diffracts the received light so that diffracted wavelengths of the light in first and second primary colours are coupled into the first waveguide 6, and so that diffracted wavelengths of the light in second and third primary colours are coupled out of the first waveguide in a direction towards the second waveguide 4. A second input diffraction grating 10 receives light coupled out of the first waveguide 6 and diffracts the second and third primary colours so that they are coupled into the second waveguide 4.

Abstract: An augmented reality display is disclosed. A colour projector (2) emits an image in a narrow beam comprising three primary colours: red, green and blue. A pair of waveguides (4, 6) is provided in the path of the projected beam. A first input grating (8) receives light from the projector (2) and diffracts the received light so that diffracted wavelengths of the light in first and second primary colours are coupled into the first waveguide (6), and so that diffracted wavelengths of the light in second and third primary colours are coupled out of the first waveguide in a direction towards the second waveguide (4). A second input diffraction grating (10) receives light coupled out of the first waveguide (6) and diffracts the second and third primary colours so that they are coupled into the second waveguide (4).

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: A waveguide (1) for use in an augmented reality or virtual reality display, comprising: an output diffractive element comprising a plurality of optical structures (22, 28, 26) in a photonic crystal; a first major surface of the waveguide, and a second major surface of the waveguide, the first major surface separated in a direction perpendicular to a plane of the waveguide from the second major surface, wherein light propagates along the waveguide towards the output diffractive element by undergoing total internal reflection between the first and second major surfaces wherein the plurality of optical structures (22, 28, 26) are arranged in a plane of the waveguide in an array which is configured to receive light from an input direction and diffract the light into a plurality of orders, some of the orders being diffracted in the plane of the waveguide at an angle to the input direction to provide 2D expansion across the plane of the waveguide, and other orders being out-coupled in a direction perpendicular to t

Abstract: A waveguide is disclosed for use in an augmented reality or virtual reality display. The waveguide includes a plurality of optical structures exhibiting differences in refractive index from a surrounding waveguide medium. The optical structures are arranged in an array to provide at least two diffractive optical elements overlaid on one another in the waveguide. 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 optical structures have a shape, when viewed in the plane of the waveguide, comprising a plurality of substantially straight sides having respective normal vectors at different angles and this can effectively reduce the amount of light that is coupled out of the waveguide on first interaction with the optical structures.

Abstract: A waveguide is disclosed for use in an augmented reality or virtual reality display. The waveguide includes a plurality of optical structures (10, 20, 30, 40, 50, 60, 70, 80) exhibiting differences in refractive index from a surrounding waveguide medium. The optical structures are arranged in an array to provide at least two diffractive optical elements (H1, H2) overlaid on one another in the waveguide. 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 optical structures have a shape, when viewed in the plane of the waveguide, comprising a plurality of substantially straight sides having respective normal vectors at different angles and this can effectively reduce the amount of light that is coupled out of the waveguide on first interaction with the optical structures.

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: An augmented reality or virtual reality display device is disclosed. A first input grating (6; 106; 306; 406; 506) is provided on a waveguide assembly to receive light from a first projector (2; 102; 202; 302; 402; 502) and to couple the light into the at least one waveguide. A second input grating (116; 316; 416; 516) is provided to receive light from a second projector (12; 112; 212; 312; 412; 512) and couple the light into the at least one waveguide. An output diffractive optical element couples light out of the at least one waveguide towards a notional viewing position. The first projector provides light to the first input diffractive optical element in a direction that is at a first angle to a waveguide normal vector, and the second projector is configured to provide light to the second input diffractive optical element in a direction that is at a second angle to the waveguide normal vector.

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: A device is disclosed comprising a waveguide (2; 102), an input diffractive optical structure (4; 104) configured to receive light from a projector and couple the received light into the waveguide and an output diffractive optical structure (10; 110). An intermediate diffractive optical structure (6, 8; 106) is configured to receive light from the input diffractive optical structure (4; 104), provide a one-dimensional expansion of the received light, and couple the expanded light towards the output diffractive optical structure (10; 110). The output diffractive optical structure (10; 110) is configured to receive light from the intermediate diffractive optical structure and couple it towards a viewer.

Abstract: An optical structure is disclosed for use in an augmented reality display. The structure includes a waveguide (52) and an input diffractive optical structure (54) configured to receive light from a projector and couple the received light into the waveguide (52). An output diffractive optical structure (60) is configured to receive light from the input diffractive optical element (54) in an input direction, wherein the output diffractive optical structure comprises at least a first diffractive optical element (30) and a second diffractive optical element (32) with different respective diffraction efficiencies, wherein the first diffractive optical element has a relatively high diffraction efficiency and the second diffractive optical element has a relatively low diffraction efficiency and the first and second diffractive optical elements are overlaid on one another in or on the waveguide. The output diffractive optical structure (60) comprises a first portion (62) and a second portion (64).