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.

Abstract: A directional illumination apparatus comprises a waveguide with a reflective surface comprising reflective pairs of light input facets, reflective light extraction facets and an output transmissive surface. An array of micro-LEDs is arranged to illuminate the reflective surface in a rearwards direction. The pairs of light input facets direct light within the waveguide and reflective light extraction facets cooperate to provide a uniform output illumination across the output aperture of the waveguide with collimated light. A thin and efficient illumination apparatus may be used for high dynamic range display backlighting, privacy display or environmental illumination applications.

Abstract: A switchable backlight for a switchable privacy display apparatus comprises a collimated backlight arranged to provide two off-axis beams and at least one polar control liquid crystal retarder arranged between parallel polarisers. The alignment layers of the liquid crystal retarder are rotated with respect to the electric vector transmission direction of the polarisers. In use in the centre stack of a vehicle, in one mode of operation high image luminance and high image visibility is provided for the passenger while the image is invisible to the driver. In another mode of operation an image is provided to the driver with low stray light to the passenger for night time operation. In a third mode of operation both passenger and driver can see an image with high luminance and image visibility.

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 privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. 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. Further, display reflectivity is reduced for on-axis reflections of ambient light, while reflectivity is increased for off-axis light. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction and increased frontal reflectivity to ambient light. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

Abstract: A switchable directional illumination apparatus comprises first and second arrays of LEDs, some of which are micro-LEDs; an aligned catadioptric micro-optic array and an aligned light guide array. In a first mode a narrow angular output is provided by a first micro-LED array and catadioptric micro-optics. In a second mode a wider angular output is provided by the second LED array and light guides. A thin and efficient illumination apparatus may be used for switching illumination in environmental lighting, display backlighting or direct display.

Abstract: An illumination apparatus comprises a first substrate; an optical structure; an array of light emitting elements disposed between the first substrate and the optical structure and an array of passive optical nanostructures disposed between the first substrate and the optical structure. Each of the passive optical nanostructures are disposed on a respective one of the light emitting elements and each passive optical nanostructure comprises an air gap. Each passive optical nanostructure is disposed between its respective light emitting element and the optical structure, wherein each passive optical nanostructure is configured to receive light emitted by its respective light emitting element, pass the received light, and output the pass light towards the optical structure.

Abstract: A control system for a switchable privacy display apparatus comprises an ambient light sensor and a display luminance controller arranged to control the luminance of the display in response to measured illuminance. High image visibility is provided for public mode operation while in privacy mode visual security level above a perceived privacy threshold may be obtained by means of control of image luminance, in response to the output of the ambient light sensor.

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 privacy display apparatus comprises a polarised output spatial light modulator, and an additional polariser. A reflective polariser, switchable liquid crystal polar control retarder, passive polar control retarders and air gap are arranged between the display output polariser and additional polariser. The passive retarders are arranged to provide no phase difference to polarised light from the spatial light modulator for on-axis light; and simultaneously provide a non-zero phase difference for polarised light in off-axis directions. The polar control retarders are further arranged to achieve low reflectivity for light propagating through the air gap. A switchable privacy display that can be conveniently assembled at low cost can be provided with high contrast images for display users while maintaining high visual security level for off-axis snoopers.

Abstract: A backlight includes a directional waveguide and a light source array, for providing large area directed illumination from localized light sources. Interfaces are provided between the directional waveguide and optical components adjacent the directional waveguide such that the coefficient of friction at the waveguide interfaces is greater than the coefficient of friction at least one outer interface on each side of the waveguide in the stack. Damage from compressive forces on the optical stack may be reduced, achieving improved optical performance and lifetime. Privacy display, low stray light display and autostereoscopic display may be provided with high uniformity, long lifetime and reduced cost mechanical components.

Abstract: A directional illumination apparatus comprises a waveguide with a reflective surface comprising reflective light input facets, reflective light extraction facets and an output transmissive surface. An array of sub-arrays of micro-LEDs is arranged to illuminate the reflective surface in a rearwards direction. The reflective light extraction facets cooperate to provide a uniform output illumination across the output aperture of the waveguide with collimated light that is controllable by control of the sub-arrays of micro-LEDs. A thin and efficient illumination apparatus may be used for switching high dynamic range display backlighting, privacy display or environmental illumination applications.

Abstract: A directional illumination apparatus comprises a waveguide with a reflective surface comprising reflective pairs of light input facets, reflective light extraction facets and an output transmissive surface. An array of micro-LEDs is arranged to illuminate the reflective surface in a rearwards direction. The pairs of light input facets direct light within the waveguide and reflective light extraction facets cooperate to provide a uniform output illumination across the output aperture of the waveguide with collimated light. A thin and efficient illumination apparatus may be used for high dynamic range display backlighting, privacy display or environmental illumination applications.

Abstract: A display comprises a polarised output spatial light modulator, switchable liquid crystal retarder, absorbing polariser and touch panel electrodes. The electrodes of the switchable liquid crystal retarder shield the touch panel electrodes from the electrical noise of the spatial light modulator addressing. The touch panel control and sensing may be synchronised with the driving signal of the switchable liquid crystal retarder. The touch panel may be operated independently of the timing of the data addressing of the spatial light modulator.

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 directional backlight comprises an array of mini-LEDs and an optical waveguide with first and second light guiding surfaces comprising apertures aligned to the array of mini-LEDs. A light turning element is 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 at least one guiding surface and an opposing surface so that a collimated output is provided with reduced power consumption and increased dynamic range in comparison to conventional backlights. A switchable privacy display with high visual security in privacy mode may be achieved.

Abstract: A switchable privacy display apparatus comprises a spatial light modulator, a light control film, and a polar control retarder that comprises plural retarders arranged between a display polariser of the spatial light modulator and an additional polariser. The display achieves high image visibility to an off-axis user in a public mode of operation and high image security to an off-axis snooper in privacy mode of operation.

Abstract: A switchable directional display apparatus comprises a spatial light modulator and a backlight comprising a waveguide, two light sources arranged to provide illumination through the edge of the waveguide and a switchable liquid crystal retarder. The light sources and switchable liquid crystal retarder may be controlled to provide a first operating state with a narrow field of view and a second operating state with a wide field of view. Image visibility in wide angle mode of operation may be maximised while visual security level may be maximised in a narrow angle mode of operation, to provide an efficient privacy mode of operation.

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 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.