Abstract: A method of calculating a sub-hologram of a virtual image point for an optical system includes determining an area delimited by straight line paths from the virtual image point to the perimeter of an entrance pupil of a viewer. The area includes a first area component on a first virtual replica of a display device and a second area component on a second virtual replica of the display device. The method also includes determining a first sub-hologram component of the virtual image point within the first area component and a second sub-hologram component of the virtual image point within the second area component. The method additionally includes superimposing the first sub-hologram component and second sub-hologram component to form a sub-hologram of the virtual image point. The method further includes applying a local phase-ramp function to at least one of the first area component and second area component.

Abstract: A waveguide arranged as a pupil expander for a display system is disclosed. The waveguide comprises a pair of opposing surfaces arranged to guide a light field therebetween by internal reflection. An input port is arranged to receive light from the display system. A reflective element is arranged to internally reflect the light field. The input port and reflective element are formed on a second surface of the pair of opposing surfaces. An output port is formed on a first surface of the pair of opposing surfaces by a transmissive-reflective element configured to divide the light field at each internal reflection therefrom such that a plurality of replicas of the light field are transmitted out of the waveguide through the output port.

Abstract: A waveguide includes a pair of complementary surfaces arranged to provide waveguiding therebetween. A first surface of the pair of complementary surfaces includes a plurality of first layers and a plurality of second layers. Each first layer includes a first dielectric. Each second layer includes a second dielectric. Each first and second layer has a first end and a second end. A percentage change in the thickness of each layer from the first end to the second end of that layer has one of a plurality of discrete allowable values. The total number of first and second layers is greater than the total number of discrete allowable values. A difference in refractive index between the first dielectric and second dielectric is greater than 0.4.

Abstract: A method including determining, from a first hologram of an image, a second hologram of a portion of the image. The method includes providing or receiving the first hologram of the image. The method further includes propagating a complex field corresponding to the first hologram from a hologram plane to an image plane. The method further includes modifying amplitudes of the complex field in the image plane by setting amplitude components of the complex field that correspond to regions of the image that are outside of the portion of the image to be zero. The method further includes propagating the modified complex field back from the image plane to the hologram plane thereby obtaining the second hologram of the portion of the image.

Abstract: A method of manufacturing a light control film includes providing a plurality of alternating layers of transparent material and light absorbing material. Each layer of light absorbing material is interspersed between respective layers of transparent material. The plurality of alternating layers are stacked in a stacking direction perpendicular to the plane of a surface of at least one of the plurality of alternating layers. The method includes cutting the plurality of alternating layers in a first and second cutting plane resulting in an intermediate film including a first cut surface parallel to the first cutting plane and a second cut surface parallel to the second cutting plane. Each of the first and second cutting planes is orientated at an angle less than or equal to 90° to the stacking direction. The method includes hot embossing the repeating prismatic structure on the first cut surface of the intermediate film resulting in a serrated/corrugated first surface.

Abstract: A method of manufacturing a light control film. The method includes providing a plurality of alternating layers of transparent material and light absorbing material, where the alternating layers of transparent material and light absorbing material are stacked in a stacking direction. The method also includes cutting, with a triangle wave-shaped edge, across the plurality of alternating layers of transparent material and light absorbing material in a first cutting plane and a second cutting plane thereby resulting in the light control film including a serrated first surface and a serrated second surface, wherein each of the first and second cutting planes is orientated at an angle less than 90° to the stacking direction. The triangle wave-shaped edge includes a cutting edge with a triangular wave shape perpendicular to the first and/or second cutting plane.

Abstract: A display system and light control layer is described. The display system includes an optical component having a reflective surface. A light control layer is disposed on a first surface of the optical component on an optical path of sunlight to the reflective surface. The light control layer includes a louvre structure including an array of louvres. Each louvre is arranged at an orientation angle relative to the first surface. The separation between adjacent/neighbouring louvres is such that the distal end/edge of one louvre overlaps the proximal end/edge of the adjacent/neighbouring louvre.

Abstract: A projection assembly is described. The projection assembly comprises a first holographic projection channel configured to output a first holographic light field. The projection assembly further comprises a second holographic projection channel configured to output a second holographic light field. The first holographic projection channel and the second holographic projection channel are arranged such that the first holographic light field is adjoined with the second holographic light field in order to form a continuous field of view.

Abstract: A method is provided of manufacturing a waveguide comprising an input port, an output port, a transparent medium having a first refractive index (n1), a first pair of opposing surfaces and a second pair of opposing surfaces. The method comprises polishing at least one surface of the second pair of opposing surfaces to achieve a separation therebetween, bonding a protective layer to at least one polished surface of the second pair of opposing surfaces; and polishing at least one surface of the first pair of opposing surfaces to achieve a separation therebetween.

Abstract: A display system comprises a two-dimensional pupil expander. The pupil expander comprises a first replicator, a coupling element and a second replicator. The first replicator is arranged to receive a holographic light field and replicate the holographic light field in a first direction. The holographic light field is diverging. The coupling element comprises a reflective-transmissive surface arranged to receive the output of the first replicator and a reflective surface, opposing the reflective-transmissive surface, in order to guide at least a portion of the holographic light field by internal reflection therebetween to an output port of the coupling element and to reduce the size of the holographic light field in a second direction. The second replicator has an input port arranged to receive the output of the coupling element and replicate the holographic light field in the second direction, wherein the second direction is perpendicular to the first direction.

Abstract: A light engine arranged to form an image visible from a viewing window. The light engine comprises: a display device arranged to display a hologram of the image and spatially modulate light in accordance with the hologram; a hologram replicator arranged to receive the spatially modulated light and provide a plurality of different light propagation paths for the spatially modulated light from the display device to the viewing window; and a control device disposed in an optical path between the first replicator and the second replicator. The control device is angled such that light from the first replicator is incident at an acute angle on the control device, and each cell of the array is switchable between a first state and a second state.

Abstract: A waveguide comprising a pair of parallel surfaces arranged to provide waveguiding therebetween. A first surface of the pair of parallel surfaces comprises a plurality of layers of a first dielectric and a plurality of layers of second dielectric arranged in an alternating configuration. Each layer of the first and second dielectric has a first end and a second end. A percentage change in the thickness of each layer from the first end to the second end of that layer has one of a plurality of discrete allowable values. The total number of layers of the first and second dielectric is greater than the total number of discrete allowable values. A difference in refractive index between the first dielectric and second dielectric is greater than 0.4.

Abstract: A pupil expander for a head-up display. The head-up display has an eye-box having a first dimension and second dimension. The pupil expander comprises a pair of first waveguides each arranged to replicate a pupil in the first dimension of the eye-box. Each waveguide is elongated and tapered in the direction of elongation such that its input end is narrower than its output end. The first waveguides are arranged so that their input ends are substantially proximate each other and their respective output ends are substantially distal from each other.

Abstract: Disclosed embodiments include a display system comprising an eye-box from which virtual images formed by the display system are visible. In some embodiments, the display system includes an image projector arranged to project a virtual image at a virtual image distance from the eye-box, and a user-tracking system arranged to determine an eye-box position of a user within the eye-box and a confidence value associated with the determined eye-box position. In some embodiments, the image projector is arranged to (i) project the virtual image at a finite virtual image distance after determining that the confidence value is above a threshold value and (ii) project the virtual image at an infinite virtual image distance after determining that the confidence value is below the threshold value.

Abstract: A diffractive structure arranged to spatially modulate light transformable by a viewing system into a target image. The diffractive structure is configured to generate a plurality of discrete light patterns. Each light pattern corresponds to a different part of the target image. The shape of each discrete light pattern substantially corresponds to the shape of an entrance aperture of the viewing system.

Abstract: A head-up display for a vehicle comprises an optical component having a reflective surface arranged, during head-up display operation, in a configuration that is conducive to sunlight glare. A light control layer is disposed on the optical component to receive sunlight on an optical path to the reflective surface. The light control layer comprises a sunlight-receiving surface and a core material separating an array of louvres. The sunlight-receiving surface of the light control layer is serrated in coordination with the array of louvres so as to deflect received sunlight away from the eye-box of the head-up display.

Abstract: A head-up display for a vehicle comprises an optical component having a reflective surface arranged, during head-up display operation, in a configuration that is conducive to sunlight glare. A light control layer is disposed on the optical component to receive sunlight on an optical path to the reflective surface. The light control layer comprises a sunlight-receiving surface and a core material separating an array of louvres. The sunlight-receiving surface of the light control layer is serrated in coordination with the array of louvres so as to deflect received sunlight away from the eye-box of the head-up display.

Abstract: A method of projecting a first image and a second image using one multi-wavelength hologram. The first image is different to the second image. The multi-wavelength hologram is arranged for illumination by light of a first wavelength to project the first image. The multi-wavelength hologram is further arranged for illumination by light of a second, shorter wavelength to project the second image.

Abstract: A light shuttering device comprises a plurality of liquid crystal cells, wherein each liquid crystal cell is operable in a first optical state or a second optical state in response to a respective first or second drive signal. A drive circuit comprises a plurality of switches and a drive controller. Each switch is arranged to output the respective first or second drive signal to a respective liquid crystal cell. The drive controller is arranged to sequentially update the output of each switch during an update cycle. The drive circuit is arranged to determine the order in which the switches are sequentially updated during an update cycle based on any changes to the respective drive signals that will be made during the update.

Abstract: A light engine arranged to form an image visible from a viewing window. The light engine comprises: a display device arranged to display a hologram of the image and spatially modulate light in accordance with the hologram; a hologram replicator arranged to receive the spatially modulated light and provide a plurality of different light propagation paths for the spatially modulated light from the display device to the viewing window; and a control device disposed in an optical path between the first replicator and the second replicator. The control device is angled such that light from the first replicator is incident at an acute angle on the control device, and each cell of the array is switchable between a first state and a second state.