Abstract: An autostereoscopic 3D display includes a spatial light modulator, for instance of the liquid crystal display type. A backlight and a mask form a plurality of light sources which are imaged by a lenticular screen at first notional viewing windows. A parallax barrier controls the visibility of pixels of the spatial light modulator to form second notional viewing windows. The display forms actual viewing windows whose lateral extent is equal to the product of the lateral extents of the first and second viewing windows and is less than each of these lateral extents.

Abstract: A directional display comprises a display arrangement such as a spatial light modulator and a rear parallax barrier illuminated by a suitable backlight. The spatial light modulator and the parallax barrier cooperate to produce Fresnel diffraction which results in spatially non-uniform brightness across viewing windows of the display. Also, where the spatial light modulator has pixels of non-constant vertical aperture, further variations in the intensity profile at the windows occurs. In order to compensate for this, a mask is provided, for instance between the parallax barrier and the backlight. The mask cooperates with the parallax barrier to produce an intensity pattern having variations which are the inverse of the variations in intensity pattern produced by the parallax barrier and the spatial light modulator. The variations are superimposed and substantially cancel each other out so as to result in viewing windows which have substantially uniform light intensities.

Abstract: A directional display comprises a display arrangement such as a spatial light modulator and a rear parallax barrier illuminated by a suitable backlight. The spatial light modulator and the parallax barrier cooperate to produce Fresnel diffraction which results in spatially non-uniform brightness across viewing windows of the display. Also, where the spatial light modulator has pixels of non-constant vertical aperture, further variations in the intensity profile at the windows occurs. In order to compensate for this, a mask is provided, for instance between the parallax barrier and the backlight. The mask cooperates with the parallax barrier to produce an intensity pattern having variations which are the inverse of the variations in intensity pattern produced by the parallax barrier and the spatial light modulator. The variations are superimposed and substantially cancel each other out so as to result in viewing windows which have substantially uniform light intensities.

Abstract: A parallax barrier includes a polarization modifying layer having aperture regions, for supplying light of a second polarization when receiving light of a first polarization, separated by barrier regions, for supplying light of a third polarization different from the second polarization when receiving light of the first polarization, and a polarizer selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarization of light passing therethrough. The polarizer passes light of the second polarization and blocks light of the third polarization in the first mode and passes light of the third polarization in the second mode.

Abstract: An observer tracking directional display comprises a spatial light modulator associated with a movable parallax optic. An observer tracker determines the position of an observer and controls the position of the optic by way of an electromechanical transducer and a mechanical transmission. The mechanical tracking arrangement has a plurality of stationary positions for the parallax optic relative to the spatial light modulator (SLM) and steps between these positions so as to optimize the viewing windows for the current position of the observer.

Abstract: A parallax barrier includes a polarisation modifying layer having aperture regions, for supplying light of a second polarisation when receiving light of a first polarisation, separated by barrier regions, for supplying light of a third polarisation different from the second polarisation when receiving light of the first polarisation, and a polariser selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarisation of light passing therethrough. The polariser passes light of the second polarisation and blocks light of the third polarisation in the first mode and passes light of the third polarisation in the second mode.

Abstract: A directional display comprises a display arrangement such as a spatial light modulator and a rear parallax barrier illuminated by a suitable backlight. The spatial light modulator and the parallax barrier cooperate to produce Fresnel diffraction which results in spatially non-uniform brightness across viewing windows of the display. Also, where the spatial light modulator has pixels of non-constant vertical aperture, further variations in the intensity profile at the windows occurs. In order to compensate for this, a mask is provided, for instance between the parallax barrier and the backlight. The mask cooperates with the parallax barrier to produce an intensity pattern having variations which are the inverse of the variations in intensity pattern produced by the parallax barrier and the spatial light modulator. The variations are superimposed and substantially cancel each other out so as to result in viewing windows which have substantially uniform light intensities.

Abstract: A directional display comprises a display arrangement such as a spatial light modulator and a rear parallax barrier illuminated by a suitable backlight. The spatial light modulator and the parallax barrier cooperate to produce Fresnel diffraction which results in spatially non-uniform brightness across viewing windows of the display. Also, where the spatial light modulator has pixels of non-constant vertical aperture, further variations in the intensity profile at the windows occurs. In order to compensate for this, a mask is provided, for instance between the parallax barrier and the backlight. The mask cooperates with the parallax barrier to produce an intensity pattern having variations which are the inverse of the variations in intensity pattern produced by the parallax barrier and the spatial light modulator. The variations are superimposed and substantially cancel each other out so as to result in viewing windows which have substantially uniform light intensities.

Abstract: An optical device includes a plurality of picture elements the phase and/or amplitude transmission of which vary in the lateral direction of the optical device reducing the level of diffraction caused by the device.

Abstract: A passive polarisation modulating optical element comprises a layer of birefringent material. The layer has substantially fixed birefringence and comprises retarder regions forming a regular pattern, for instance to act as a parallax barrier for a 3D display. The retarders have optic axes aligned in different directions from each other. The element may be associated with a polariser, for instance an output polariser of a liquid crystal device, with the polarising direction of the polariser being parallel to the optic axis of the retarders. Thus, the retarders have no effect on the intensity of light passing through the element whereas the retarders act as half waveplates and rotate the polarisation vector of light passing therethrough, for instance by 90.degree..

Abstract: An autostereoscopic display comprises an SLM which is controlled to provide an image display and a signal display. A parallax optic has a first portion which cooperates with the image display to form a plurality of viewing windows. A second portion of the parallax optic forms first and second images visible to an observer at alternate viewing windows so as to allow the observer to distinguish between desired orthoscopic viewing zones and undesirable viewing positions such as pseudoscopic positions.

Abstract: A parallax barrier includes a polarisation modifying layer having aperture regions, for supplying light of a second polarisation when receiving light of a first polarisation, separated by barrier regions, for supplying light of a third polarisation different from the second polarisation when receiving light of the first polarisation, and a polariser selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarisation of light passing therethrough. The polariser passes light of the second polarisation and blocks light of the third polarisation in the first mode and passes light of the third polarisation in the second mode.

Abstract: Observer tracking is provided in an autostereoscopic 3D display, for instance of the type including an LCD panel 2 behind a parallax barrier. An infrared sensor such as a position sensitive detector is provided on the LCD panel. The parallax barrier extends over the detector so as to form an image of the observer or of a reflective target worn by the observer on the detector. The parallax barrier is moved so as to keep the image at a constant position on the detector. The viewing zone thus track the observer.

Abstract: A stereoscopic 3D display comprises a light source and condenser optics which direct light through a spatial light modulator and a polarisation modulator. Each of the modulators is pixellated with the pixels of one modulator being optically aligned with respective pixels of the other modulator. Each pixel of the spatial light modulator is controlled so as to provide a light amplitude which is equal to the square root of the sum of the squares of the corresponding pixels of the stereoscopic images. Each pixel of the polarisation modulator is controlled so as to supply output light with a polarisation angle give by the arc-tangent of the quotient of the pixel amplitudes of the stereoscopic images. Polarising glasses with suitably aligned polariser lenses allow an observer to perceive the 3D effect, for instance on a polarisation preserving screen on which the encoded stereoscopic image is projected by projection optics.

Abstract: An autostereoscopic display includes a display device and an optical system which provide laterally overlapping viewing windows wherein one viewing window may receive black view data while an adjacent viewing window receives eye view data. Such a display may be used to perform observer tracking.

Abstract: A spatial light modulator comprises a plurality of picture elements arranged as rows and columns. The columns are arranged as adjacent groups, for instance for association with an element of a parallax device to provide an autostereoscopic 3D display. Adjacent picture elements disclosed in each row and in adjacent columns of each group overlap horizontally so that there are overlapping regions and non-overlapping regions. The vertical extent of each picture element is substantially constant throughout the non-overlapping region and is substantially equal to the sum of the heights of the adjacent picture elements throughout the overlapping regions.

Abstract: An observer tracking display is provided in which the image data displayed by at least three image displays along respective different directions is updated depending on the lateral position of an observer. The image displayed in a viewing region not visible to the observer is updated with an appropriate image in anticipation of the observer moving to a position where that viewing region is visible.

Abstract: A calibration method is provided for an observer tracking display, for instance of the autostereoscopic 3D type, which forms steerable viewing zones and which comprises a tracking system for tracking an observer and a controller for controlling the viewing zones in response to the tracking system. The viewing zones are steered to direct light in a plurality of directions in turn. The observer then moves to the optimum position for viewing the display. The tracking system determines the optimum position for each viewing zone direction and the positions and directions are stored in association with each other so as to form a mapping in the controller for controlling the viewing zones in response to the tracking system during normal use of the display.