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 light turning element and a method fabricating such a light turning element are described. The light turning element comprises a layer of liquid crystal material. The layer of liquid crystal material defining a plane. The layer of liquid crystal material is configured such that an angle (?) between a director (n) of the liquid crystal material and a first dimension (x) is an oscillating function of position in the first dimension x. The first dimension x is a dimension within the plane.

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 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 having a viewing window on a viewing plane, the display system comprising a picture-generating unit and an imaging system, where the picture-generating unit displays a picture on a display plane that is a holographic reconstruction formed from a hologram of the picture. The imaging system comprises a projection lens disposed between the display plane and viewing plane, an aperture stop, and a waveguide pupil expander. The projection lens comprises a pair of planar surfaces that define the boundaries of the projection lens, the aperture stop restricts the aperture of the projection lens in the first direction and forms the limiting aperture stop of the imaging system, and the waveguide pupil expander receives light of the picture from the projection lens through the aperture stop and replicates the aperture stop to expand the viewing window of the display system.

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 method and system for reducing the effects of glare in a system comprising a picture generating unit, such as a holographic projector. The system may be a head-up display (HUD), which is configured to display a picture to a viewer, without requiring the user to look away from their usual viewpoint. The HUD system may be comprised within a vehicle. The glare in the system may be caused by light being incident on a surface comprising a screen or a window, through which the user looks at their usual viewpoint. The surface may comprise a windshield in a vehicle. The light that causes the glare may be ambient light. The method and system are provided for reducing the effects of glare in a system that comprises a waveguide in conjunction with the picture generating unit. The waveguide may be operable to act as an exit pupil expander.

Abstract: A display device, a photomask for a display device and a method for fabricating a display device comprising the photomask is described. The display device comprises a plurality of pixels arranged to spatially modulate light having a first characteristic. The display device further comprises a pixel mask structure. The pixel mask structure comprises a diffractive pattern that is configured to diffract light having the first characteristic and to transmit light having a second characteristic (without diffraction). The diffractive pattern of the pixel mask structure substantially surrounds the plurality of pixels.

Abstract: There is disclosed herein a liquid crystal on silicon spatial light modulator, “LCoS SLM”, device arranged for in-plane switching. The LCoS SLM device comprises: a silicon backplane (1501); a transparent substrate (1581); a liquid crystal layer (1571); an electrode structure (1505, 1507) and a reflective component (1561, 1551). The liquid crystal layer (1571) is interposed between the silicon backplane (1501) and the transparent substrate (1581). The electrode structure (1505, 1507) is formed on the silicon backplane (1501) for generating an electric field in the liquid crystal layer (1571). The electric field is substantially parallel to the silicon backplane (1501). The reflective component (1551, 1561) is opposing the transparent substrate (1581).

Abstract: A method of calculating a hologram having an amplitude and a phase component. The method comprises (i) receiving an input image comprising a plurality of data values representing amplitude. The method then comprises (ii) assigning a random phase value to each data value of the plurality of data values to form a complex data set. The method then comprises (iii) performing an inverse Fourier transform of the complex data set. The method then comprises (iv) constraining each complex data value (X1, X2) of the transformed complex data set to one of a plurality of allowable complex data values (GL1-GL8), each comprising an amplitude modulation value and a phase modulation value, to form a hologram, wherein, the phase modulation values (GL1-GL7) of the plurality of allowable complex data values substantially span at least 3?/2 and at least one of the allowable complex data values has an amplitude modulation value of substantially zero (GL8) and a phase modulation value of substantially zero.

Abstract: There is disclosed a projector arranged to project a light pattern. The projector comprises a spatial light modulator and a light source. The spatial light modulator has an array of pixels arranged to display a phase pattern. The array of pixels may be a substantially planar array of pixels. Each pixel comprises liquid crystals having a director rotatable in a plane of rotation between a first direction and a second direction. The light source is arranged to illuminate the array of pixels with polarised light such that the light is spatially-modulated in accordance with the phase pattern to form the light pattern. It may be said that the light pattern corresponds to the phase pattern. The angle of incidence of the light on the array of pixels is greater than zero and the light is s-polarised. The first direction is parallel to the polarisation direction of the light. The second direction is in the plane of incidence.

Abstract: There is provided a holographic projector comprising a reflective liquid crystal display device. The reflective liquid crystal display device comprises a light-modulating layer between a first substrate and a second substrate substantially parallel to the first substrate. The light-modulating layer comprises planar-aligned nematic liquid crystals having positive dielectric anisotropy. The first substrate is substantially transparent and comprises a first alignment layer arranged to impart a first pre-tilt angle ?? on liquid crystals proximate the first substrate, wherein ?1>5°. The second substrate is substantially reflective and comprises a second alignment layer arranged to impart a second pre-tilt angle ?2 on liquid crystals proximate the second substrate, wherein ?2>5°. The reflective liquid crystal display device further comprises a plurality of pixels defined on the light-modulating layer having a pixel repeat distance x, wherein x?10 ?m.

Abstract: A method and system for reducing the effects of glare in a system comprising a picture generating unit, such as a holographic projector. The system may be a head-up display (HUD), which is configured to display a picture to a viewer, without requiring the user to look away from their usual viewpoint. The HUD system may be comprised within a vehicle. The glare in the system may be caused by light being incident on a surface comprising a screen or a window, through which the user looks at their usual viewpoint. The surface may comprise a windshield in a vehicle. The light that causes the glare may be ambient light. The method and system are provided for reducing the effects of glare in a system that comprises a waveguide in conjunction with the picture generating unit. The waveguide may be operable to act as an exit pupil expander.

Abstract: A holographic display method includes calculating a hologram, displaying it on a spatial light modulator (SLM) and illuminating it with coherent light. The hologram includes hologram pixels each having a hologram pixel value. The hologram is calculated using steps including: performing the inverse Fourier transform of the product of an object field and a negative quadratic phase exponential representative of positive optical power; and restricting each calculated hologram pixel value to one of a plurality (greater than two) of allowable pixel values to form a constrained hologram, which is displayed on the SLM. Each light-modulating pixel of the SLM is operable in a plurality of light-modulation levels corresponding to the plurality of allowable pixel values. The SLM is illuminated with coherent light to form a replay field including conjugate images: a real holographic reconstruction and a virtual holographic reconstruction having greater intensity than that of the real holographic reconstruction.

Abstract: There is provided a holographic projector comprising a reflective liquid crystal display device. The reflective liquid crystal display device comprises a light-modulating layer between a first substrate and a second substrate substantially parallel to the first substrate. The light-modulating layer comprises planar-aligned nematic liquid crystals having positive dielectric anisotropy. The first substrate is substantially transparent and comprises a first alignment layer arranged to impart a first pre-tilt angle ?l on liquid crystals proximate the first substrate, wherein ?1>5°. The second substrate is substantially reflective and comprises a second alignment layer arranged to impart a second pre-tilt angle ?2 on liquid crystals proximate the second substrate, wherein ?2>5°. The reflective liquid crystal display device further comprises a plurality of pixels defined on the light-modulating layer having a pixel repeat distance x, wherein x?10 ?m.

Abstract: A method of calculating a hologram having an amplitude and a phase component. The method comprises (i) receiving an input image comprising a plurality of data values representing amplitude. The method then comprises (ii) assigning a random phase value to each data value of the plurality of data values to form a complex data set. The method then comprises (iii) performing an inverse Fourier transform of the complex data set. The method then comprises (iv) constraining each complex data value (X1, X2) of the transformed complex data set to one of a plurality of allowable complex data values (GL1-GL8), each comprising an amplitude modulation value and a phase modulation value, to form a hologram, wherein, the phase modulation values (GL1-GL7) of the plurality of allowable complex data values substantially span at least 3?/2 and at least one of the allowable complex data values has an amplitude modulation value of substantially zero (GL8) and a phase modulation value of substantially zero.

Abstract: An illumination system is arranged to output a light beam for illuminating a scene. The system comprises a spatial light modulator arranged to receive incident light, and to output light comprising a first component and a second component. The first component comprises incident light that is output without modulation by the spatial light modulator. The second component comprises incident light that is spatially-modulated according to a hologram and output by the spatial light modulator. A control device is operable to control the proportion of light output by the spatial light modulator that corresponds to the second component.

Abstract: A display system includes a data provider, a spatial light modulator and a second cylindrical lens. The data provider is arranged to provide holographic data comprising first data corresponding to a first cylindrical lens having optical power in a first direction. The spatial light modulator is arranged to receive the holographic data, wherein the spatial light modulator is arranged to spatially-modulate received light in accordance with the holographic data. The second cylindrical lens is arranged to receive spatially-modulated light from the spatial light modulator and perform a one-dimensional Fourier transform of the received light in a second direction orthogonal to the first direction.

Abstract: A holographic display method includes calculating a hologram, displaying it on a spatial light modulator (SLM) and illuminating it with coherent light. The hologram includes hologram pixels each having a hologram pixel value. The hologram is calculated using steps including: performing the inverse Fourier transform of the product of an object field and a negative quadratic phase exponential representative of positive optical power; and restricting each calculated hologram pixel value to one of a plurality (greater than two) of allowable pixel values to form a constrained hologram, which is displayed on the SLM. Each light-modulating pixel of the SLM is operable in a plurality of light-modulation levels corresponding to the plurality of allowable pixel values. The SLM is illuminated with coherent light to form a replay field including conjugate images: a real holographic reconstruction and a virtual holographic reconstruction having greater intensity than that of the real holographic reconstruction.

Abstract: A LCOS routing device, comprising: an optical input and plurality of optical outputs; a spatial light modulator (SLM) between said input and output, for displaying a kinoform; a data processor, configured to provide kinoform data for displaying said kinoform on said SLM. Said data processor inputs routing and calculates said kinoform data. Said data processor calculates kinoform data by: determining an initial phase pattern for said kinoform; calculating a replay field of said phase pattern; modifying an amplitude component of said replay field, retaining a phase component of said replay field to provide an updated replay field; performing a space-frequency transform on said updated replay field to determine an updated phase pattern for said kinoform; and repeating said calculating and updating of said replay field and said performing of said space-frequency transform until said kinoform for display is determined; and outputting said kinoform data for display on said LCOS SLM.