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 control system for a switchable privacy display apparatus comprises an ambient light sensor, a controllable light source and a display controller arranged to control the light source and the display luminance. 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 and display illuminance, in response to the output of the ambient light sensor.

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 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 switchable privacy display for an automotive vehicle comprises a spatial light modulator, a first switchable liquid crystal retarder and first passive retarder arranged between a first pair of polarisers and a second switchable liquid crystal retarder and second passive retarder arranged between a second pair of polarisers. A first switchable liquid crystal retarder comprises a two homeotropic alignment layers and a second switchable liquid crystal retarder comprises two homogeneous alignment layers. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss to the passenger, whereas off-axis light has reduced luminance to reduce the visibility of the display to off-axis driver leaning towards the display. In a shared mode of operation, the liquid crystal layers are controlled so that off-axis luminance and reflectivity are unmodified.

Abstract: A switchable privacy display for an automotive vehicle comprises a spatial light modulator, a first switchable liquid crystal retarder and first passive retarder arranged between a first pair of polarisers and a second switchable liquid crystal retarder and second passive retarder arranged between a second pair of polarisers. The first switchable liquid crystal retarder comprises a homeotropic alignment layer and a homogeneous alignment layer. The second switchable liquid crystal retarder comprises two homeotropic alignment layers or two homogeneous alignment layers. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss to the passenger, whereas off-axis light has reduced luminance to reduce the visibility of the display to off-axis driver leaning towards the display. In a shared mode of operation, the liquid crystal layers are controlled so that off-axis luminance and reflectivity are unmodified.

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 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 a homeotropic alignment layer and a homogeneous alignment layer. The second switchable LC crystal retarder comprises two homeotropic alignment layers or two homogeneous alignment layers. In landscape or portrait 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. 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: 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: 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: 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 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 imaging directional backlight apparatus including a waveguide, a light source array, for providing large area directed illumination from localized light sources. The waveguide may include a stepped structure, in which the steps may further include extraction features optically hidden to guided light, propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted, diffracted, or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. The directional backlight may be arranged to switch between at least a first wide angular luminance profile mode and a second narrow angular luminance profile mode. The directional backlight is arranged to illuminate an LCD with a bias electrode arranged to switch liquid crystal directors in black state pixels between a first wide angular contrast profile mode and a second narrow angular contrast profile mode.

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: 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 privacy display comprises a liquid crystal spatial light modulator, a switchable retarder and a passive compensation retarder arranged between a pair of polarisers. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without change of image contrast, whereas off-axis light has reduced contrast to reduce the visibility of the display to off-axis snoopers over a wide polar angular range. In a wide angle mode of operation, the retardance of the switchable retarder is adjusted so that off-axis contrast is substantially unmodified.

Abstract: A directional illumination apparatus comprises a catadioptric micro-optic array comprising a reflective surface comprising light reflecting facets and an output transmissive surface comprising refractive structures. An array of micro-LEDs is arranged between the reflective surface and output transmissive surface and arranged to illuminate the reflective surface. The light reflecting facets and refractive structures cooperate to provide a uniform output illumination across the output aperture of the array with collimated output. A thin and efficient illumination apparatus may be used for switching display backlighting or environmental illumination applications.

Abstract: A control system for a switchable privacy display apparatus comprises sensors arranged to determine device location, operating environment, document type, application type and further comprises a privacy policy for control of privacy images. High image visibility is provided for public mode operation while in privacy mode a high visual security level may be obtained by means of control of image luminance, contrast and white point in response to the privacy policy.

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: 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.