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: 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 switchable privacy display comprises a spatial light modulator with output polariser, a reflective polariser, a polar control liquid crystal retarder and an additional polariser. The electrodes of the polar control liquid crystal retarder are patterned with a mark. In wide angle and narrow angle operational modes, the electrodes of the liquid crystal retarder are driven such that the mark is not visible. In a mark display state, the electrodes are driven to provide visibility of the mark in reflected light to an off-axis observer.

Abstract: A switchable backlight for a switchable privacy display apparatus comprises a collimated waveguide and an optical turning film comprising first and second arrays of elongate prismatic elements. High image luminance and image visibility is provided for off-axis viewers in a public mode of operation while in a privacy mode of operation visual security level above a perceived privacy threshold may be achieved for off-axis snoopers.

Abstract: A switchable privacy display comprises a spatial light modulator with output polariser, a reflective polariser, a polar control liquid crystal retarder and an additional polariser. The electrodes of the polar control liquid crystal retarder are patterned with a mark. In wide angle and narrow angle operational modes, the electrodes of the liquid crystal retarder are driven such that the mark is not visible. In a mark display state, the electrodes are driven to provide visibility of the mark in reflected light to an off-axis observer.

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 privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. A birefringent surface relief diffuser structure is arranged to transmit light from the display with high transparency and provide diffuse reflection of ambient light to head-on display users. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss and with low diffusion, whereas off-axis light has reduced luminance and increased diffusion. Further, overall 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, increased frontal reflectivity and diffusion of 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 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 display apparatus comprises at least one spatial light modulator and at least one curved view angle control element that comprises plural retarders arranged between the display polariser of each spatial light modulator, and an additional polariser. The curvature of the view angle control element provides increased luminance uniformity for a head-on user and increased visual security to an off-axis snooper.

Abstract: A privacy display comprises a spatial light modulator and a passive retarder arranged between first and second polarisers arranged in series with the spatial light modulator, On-axis light from the spatial light modulator is directed without loss, and 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 of view. Off-axis visibility of the display in an automotive vehicle can be reduced.

Abstract: A directional illumination apparatus comprises an array of micro-LEDs that may be organic LEDs (OLEDs) or inorganic LEDs and an aligned solid catadioptric micro-optic array arranged to provide a water vapour and oxygen barrier for the micro-LEDs as well as reduced sensitivity to thermal and pressure variations. The shape of the interfaces of the solid catadioptric micro-optic array is arranged to provide total internal reflection for light from the aligned micro-LEDs using known transparent materials. A thin and efficient illumination apparatus may be used for collimated illumination in environmental lighting, display backlighting or direct display.

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 directional illumination apparatus comprises an array of light emitting diodes formed on a support substrate, a waveguide and a light turning optical component. An array of light input wells are arranged in the waveguide to receive light from the respective aligned array of light emitting diodes. An array of light deflecting wells are arranged in the waveguide to reflect guided light in the region around each light emitting diode. Extracted light from the waveguide is output by means of refraction and total internal reflection by a light turning optical component. A directional illumination output may be provided. A backlight for a high dynamic range display may achieve high efficiency and luminance. A privacy display with high security factor and high dynamic range may be achieved.

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 arranged between a first pair of polarisers and a second switchable LC retarder and second passive retarder arranged between a second pair of polarisers. Each switchable LC retarder comprises a homeotropic alignment layer and a homogeneous alignment layer. In privacy mode, on-axis light from the SLM is directed without loss, whereas off-axis light has reduced luminance to reduce the visibility of the display 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 liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

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 display may include a waveguide. The waveguide may include light extraction features arranged to direct light from an array of light sources by total internal reflection to an array of viewing windows and a reflector arranged to direct light from the waveguide by transmission through extraction features of the waveguide to the same array of viewing windows. A further spatially multiplexed display device comprising a spatial light modulator and parallax element is arranged to cooperate with the illumination from the waveguide. An efficient and bright autostereoscopic display system with low cross talk and high resolution can be achieved.

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 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 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.