Abstract: A display device comprising a spatial light modulator having a display polariser arranged on one side is provided with an additional polariser arranged on the same side as the display polariser and a polar control retarder between the additional polariser and the display polariser. The polar control retarder includes a liquid crystal retarder having two surface alignment layers disposed adjacent to a layer of liquid crystal material on opposite sides. The surface alignment layers provide alignment in the adjacent liquid crystal material with a twist. The out-of-plane orientation of the twisted layer of liquid crystal material is modified across at least one region of the display device to provide a transmission function in response to the measured location of an off-axis snooper, achieving increased size of polar region for which desired uniformity of security factor, or reduced distraction across the display to the driver in an automotive application is achieved.

Abstract: A directional illumination device for a vehicle external light comprises an array of light sources and an imaging waveguide comprising an input surface and a reflective end. Opposed guide surfaces are arranged to guide input light from the input surface to the reflective end and back along the waveguide after reflection at the reflective end, the waveguide being arranged to extract input light as it is guided back along the waveguide after reflection and to cause the extracted light to exit through the first guide surface. The reflective end has positive optical power in the direction laterally across the waveguide and the waveguide is arranged to direct the extracted light in respective output illumination directions distributed in a lateral direction in dependence on the input positions of the light sources in the direction laterally across the waveguide. A thin, high brightness and high efficiency controllable directional vehicle headlight is provided.

Abstract: A display comprises a polarised output spatial light modulator, switchable liquid crystal retarder, absorbing polarizer and touch panel electrodes. The switchable liquid crystal layer is stabilised by a cured reactive mesogen material during application of an applied voltage. Light scatter in privacy mode is reduced and visual security level enhanced. Visibility of disclinations during application of applied pressure, for example from a finger on a touch screen is minimised.

Abstract: A switchable directional backlight for a privacy display comprises a waveguide with first and second opposing input ends and a turning film arranged to collect light output from the waveguide for input into a spatial light modulator. The waveguide has an array of light deflecting features arranged on one guiding surface and an opposing planar surface. Light deflecting features are arranged such that light input from the first input end is output with a narrow angular range and light input from the second input end is output with a wide angular range.

Abstract: Reflections from a display device are controlled using retarders arranged on the output side of a display panel which outputs light with a predetermined polarization state. First and second planes of incidence are defined in respect of first and second rays of light output from the device and first and second normals to first and second surfaces of optically transmissive material at first and second points at which the first and second rays of light are reflected. The retarders are selected to cause the polarization state of the first ray to be linearly polarized in a direction that is in the first plane of incidence, and to cause the polarization state of the second ray to be linearly polarized in a direction that is in the second plane of incidence. The reflections from the surfaces are minimized because for both surfaces the polarization direction is in-plane.

Abstract: A dual view display for an automotive vehicle comprises a spatial light modulator and a polar control retarder comprising a switchable liquid crystal retarder arranged between a first pair of polarisers. The switchable liquid crystal retarder comprises a polarisation-switch retarder and a polar control retarder with an average director that is directed towards an off-axis viewing location. In a first temporal phase of operation, the spatial light modulator and polar control retarder are arranged to direct light comprising a first image towards a first direction and in a second temporal phase of operation to direct light comprising a second image towards a second direction.

Abstract: An illumination apparatus is manufactured by selectively removing passive optical nanostructures from a monolithic array of light-emitting elements while preserving their relative spatial position. The nanostructures are selected such that, in at least one direction, for at least one pair of the selectively removed passive optical nanostructures, for each respective pair there is at least one nanostructure that is not selected that was positioned in the monolithic array between the pair of selectively removed passive optical nanostructures in the at least one direction, forming a non-monolithic array of passive optical nanostructures with the selectively removed passive optical nanostructures while preserving their relative spatial position, and aligning each of the passive optical nanostructures of the non-monolithic array with a respective light-emitting element of the non-monolithic array of light-emitting elements.

Abstract: A switchable directional backlight for a privacy display comprises a waveguide with first and second opposing input ends and a turning film arranged to collect light output from the waveguide for input into a spatial light modulator. The waveguide has an array of light deflecting features arranged on one guiding surface and an opposing planar surface. Light deflecting features are arranged such that light input from the first input end is output with a narrow angular range and light input from the second input end is output with a wide angular range.

Abstract: A switchable privacy display comprises an emissive SLM, a parallax barrier, a switchable LC retarder, and passive retarders arranged between parallel output polarisers. In privacy mode, on-axis light from the SLM is directed without loss, whereas the parallax barrier and retarder layers cooperate to increase the VSL to off-axis snoopers. The display may be rotated to achieve privacy operation in landscape and portrait orientations. In public mode, the LC retardance is adjusted so that off-axis luminance is increased so that the image visibility is increased for multiple users. The display may also switch between day-time and night-time operation, for example for use in an automotive environment. A low reflectivity emissive display for use in ambient illumination comprises a SLM with emissive pixels, an absorptive parallax barrier and a high spectral leakage optical isolator. Head-on light from the pixels is directed with increased transmission efficiency while ambient light is strongly absorbed.

Abstract: A privacy display comprises a spatial light modulator and a compensated switchable guest-host liquid crystal retarder arranged between first and second polarisers arranged in series with the spatial light modulator. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss, whereas off-axis light has reduced luminance. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction over a wide polar field. In a wide angle mode of operation, the switchable liquid crystal retardance is adjusted so that off-axis luminance is substantially unmodified.

Abstract: A colour micro-LED display apparatus comprises an array of reflective optical elements and an array of micro-LED pixels with a uniform emission colour across the array arranged between the array of reflective optical elements and an output substrate. Light from the micro-LEDs is directed into the reflective optical elements and is incident on scattering regions in the apparatus. Colour converted scattered light is transmitted by the output substrate. A thin and efficient display apparatus may be provided with high spatial and angular colour uniformity and long lifetime.

Abstract: A switchable backlight for a switchable privacy display apparatus comprises a collimated waveguide, first and second light sources and an optical turning film comprising elongate prismatic elements with facet orientations that pupillate the output of the waveguide in two orthogonal directions for each of first and second light sources. High luminance uniformity is achieved for a head-on user in privacy and public viewing modes and high uniformity of security factor is achieved for off-axis snoopers, with increased speed of privacy switch-on in privacy mode.

Abstract: A display device comprising a spatial light modulator having a display polariser arranged on one side of the spatial light modulator is provided with an additional polariser arranged on the same side as the display polariser and polar control retarders between the additional polariser and the display polariser. The polar control retarders include a liquid crystal retarder having two surface alignment layers disposed adjacent to a layer of liquid crystal material on opposite sides. The surface alignment layers provide alignment in the adjacent liquid crystal material with an in-plane component, wherein the angle of said in-plane component changes monotonically along a predetermined axis across the display device, providing reduction of luminance in directions that are offset from a viewing axis, increasing uniformity in the reduction of luminance in directions that are offset from a viewing axis.

Abstract: A display device comprising a spatial light modulator having a display polariser arranged on one side of the spatial light modulator is provided with an additional polariser arranged on the same side as the display polariser and a polar control retarder between the additional polariser and the display polariser. The polar control retarder includes a liquid crystal retarder having two surface alignment layers disposed adjacent to a layer of liquid crystal material on opposite sides. The surface alignment layers provide alignment in the adjacent liquid crystal material with a twist. The out-of-plane orientation of the twisted layer of liquid crystal material is modified across at least one region of the display device to provide a pupillated transmission function, achieving increased luminance uniformity to a display user and increased uniformity of security factor to an off-axis snooper, or reduced distraction across the display to the driver in an automotive application.

Abstract: Disclosed is an imaging directional backlight including an array of light sources, and a control system arranged to provide variable distribution of luminous fluxes, scaled inversely by the width associated with the respective light sources in the lateral direction, across the array of light sources. The luminous intensity distribution of output optical windows may be controlled to provide desirable luminance distributions in the window plane of an autostereoscopic display, a directional display operating in wide angle 2D mode, privacy mode and low power consumption mode. Image quality may be improved and power consumption reduced.

Abstract: A switchable privacy display comprises a spatial light modulator (SLM), a first switchable liquid crystal (LC) retarder and first passive retarder between a first pair of polarisers and a second switchable LC retarder and second passive retarder between a second pair of polarisers. The first switchable LC retarder comprises two homeotropic alignment layers and the second switchable LC retarder comprises two homogeneous alignment layers. In privacy mode, on-axis light from the SLM is directed without loss, whereas off-axis light has reduced luminance to reduce visibility to off-axis snoopers. The display may achieve privacy operation in landscape and portrait orientations. Further, display reflectivity may be reduced for on-axis reflections of ambient light, while reflectivity may be increased for off-axis light to achieve increased visual security. In public mode, the LC retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

Abstract: An illumination apparatus comprises a first substrate, an optical structure, an array of light emitting elements disposed on the first substrate and between the first substrate and the optical structure, and a mask comprising a plurality of apertures therein. The optical structure is configured to receive light emitted by the array of light emitting elements, direct the received light into a direction away from the first substrate, direct at least some of the light which has been directed away from the first substrate back towards the first substrate, and direct at least some of the light which has been directed back towards the first substrate through the plurality of apertures of the mask.

Abstract: An illumination apparatus is manufactured by selectively removing passive optical nanostructures from a monolithic array of light-emitting elements while preserving their relative spatial position. The nanostructures are selected such that, in at least one direction, for at least one pair of the selectively removed passive optical nanostructures, for each respective pair there is at least one nanostructure that is not selected that was positioned in the monolithic array between the pair of selectively removed passive optical nanostructures in the at least one direction, forming a non-monolithic array of passive optical nanostructures with the selectively removed passive optical nanostructures while preserving their relative spatial position, and aligning each of the passive optical nanostructures of the non-monolithic array with a respective light-emitting element of the non-monolithic array of light-emitting elements.

Abstract: An illumination apparatus comprises a plurality of LEDs aligned to an array of directional optical elements wherein the LEDs are substantially at the input aperture of respective optical elements. An electrode array is formed on the array of optical elements to provide at least a first electrical connection to the array of LED elements. Advantageously such an arrangement provides low cost and high efficiency from the directional LED array.

Abstract: A privacy display comprises a spatial light modulator and a compensated switchable liquid crystal retarder arranged between first and second polarisers arranged in series with the spatial light modulator. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss, whereas off-axis light has reduced luminance. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction over a wide polar field. In a wide angle mode of operation, the switchable liquid crystal retardance is adjusted so that off-axis luminance is substantially unmodified.