Abstract: A lighting device includes a transparent optical cavity having an exit surface including a specularly reflective material arranged to reflect light into the cavity, the exit surface having a plurality of apertures formed therein, a base surface including a specularly reflective material arranged to reflect light into the cavity, and at least one light receiving surface arranged relative to the base surface and configured to receive light from a light source. The plurality of apertures are arranged to maximize at least one of uniformity, angular distribution, efficiency or luminous intensity of light exiting the exit surface, and a distribution of light received at the light receiving surface is altered by at least one of a combination of the exit surface and the base surface, or the light receiving surface.

Abstract: A phosphor-based multi-colored display is provided which includes a spatial light modulator comprising an addressable array of apertures each corresponding to a respective sub-pixel in the display; an array of phosphor regions each indexed to a corresponding aperture of the spatial light modulator; and a backlight which provides quasi-monochromatic light to phosphor within each of the phosphor regions. The phosphor within each of the phosphor regions, upon being excited by the quasi-monochromatic light of the backlight, emits light having a color different from a color of the quasi-monochromatic light, through the corresponding aperture of the spatial light modulator.

Abstract: A backlight is provided for an at least partially transmissive display or another lighting application. The backlight comprises an array of primary light sources that emit downwards towards an arrangement of curved mirror surfaces. The light reflected by the mirror surfaces is collimated by an arrangement of lenses. The mirror surface shape, lens shape, primary light source positions and the separation between the lens and mirror surfaces are chosen to ensure a high degree of spatial uniformity as well as collimation.

Abstract: A hollow core photonic crystal fiber (HCPCF) having a wavelength of operation, the HCPCF comprising: a core region having a first refractive index; a cladding region surrounding the core region and comprising a plurality of microcapillaries arranged in a transverse structure having a pitch, the pitch of the structure being at least five times larger than the wavelength of operation, the cladding region having a second refractive index higher than the first refractive index.

Abstract: A phosphor-based multi-coloured display is provided which includes a spatial light modulator comprising an addressable array of apertures each corresponding to a respective sub-pixel in the display; an array of phosphor regions each indexed to a corresponding aperture of the spatial light modulator; and a backlight which provides quasi-monochromatic light to phosphor within each of the phosphor regions. The phosphor within each of the phosphor regions, upon being excited by the quasi-monochromatic light of the backlight, emits light having a colour different from a colour of the quasi-monochromatic light, through the corresponding aperture of the spatial light modulator.

Abstract: A display panel incorporates the functionality to determine the three dimensional position of a light reflecting or emitting object (400, 401, 410) in front of a display surface (100). An array of sensors (310) is disposed in the panel and provided with optical arrangements such as apertures in masks (321, 331) within the panel. These arrangements prevent light incident normally on the display surface (100) from reaching the sensors (310) but allow obliquely incident light (602, 604) to reach the sensors (310). The object position is determined by analyzing the sensor responses.

Abstract: An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction.

Abstract: A hollow core photonic crystal fibre (HCPCF) having a wavelength of operation, the HCPCF comprising: a core region having a first refractive index; a cladding region surrounding the core region and comprising a plurality of microcapillaries arranged in a transverse structure having a pitch, the pitch of the structure being at least five times larger than the wavelength of operation, the cladding region having a second refractive index higher than the first refractive index.

Abstract: An elongate waveguide for guiding light including a core having an elongate region of relatively low refractive index; a microstructured region around the core comprising elongate regions of relatively low refractive index interspersed with elongate regions of relatively high refractive index; and a boundary at the interface between the core and the microstructured region, the boundary including, in the transverse cross-section, a region of relatively high refractive index, which is connected to the microstructured region at a plurality of nodes, and at least one relatively enlarged region around the boundary, the enlarged region having a major dimension and a minor dimension, wherein the length of the major dimension divided by the length of the minor dimension is more than 3.0.

Abstract: An elongate waveguide for guiding light including a core having an elongate region of relatively low refractive index; a microstructured region around the core comprising elongate regions of relatively low refractive index interspersed with elongate regions of relatively high refractive index; and a boundary at the interface between the core and the microstructured region, the boundary including, in the transverse cross-section, a region of relatively high refractive index, which is connected to the microstructured region at a plurality of nodes, and at least one relatively enlarged region around the boundary, the enlarged region having a major dimension and a minor dimension, wherein the length of the major dimension divided by the length of the minor dimension is more than 3.0.

Abstract: Improved photonic band-gap optical fibre The present invention relates in particular to improved photonic band-gap optical fibres that can confine light to a core region of the fibre by the action of both a photonic band-gap cladding and an antiresonant core boundary, at the interface between the core and cladding.

Abstract: An elongate waveguide for guiding light includes a core having an elongate region of relatively low refractive index; a microstructured region around the core having elongate regions of relatively low refractive index interspersed with elongate regions of relatively high refractive index; and a boundary at the interface between the core and the microstructured region, the boundary including in the transverse cross-section, a region of relatively high refractive index, which is connected to the microstructured region at a plurality of nodes, at least one relatively enlarged region around the boundary (and excluding a boundary having twelve nodes and six enlarged regions substantially at a mid-point between six pairs of relatively more-widely-spaced apart neighboring nodes).

Abstract: Method of making protective headgear including forming a peak or visor portion and thereafer injection molding a fiber-filled resin onto the peak portion to form a shell portion, the shell portion resin containing 10-40% by weight of fibers at least 5 mm in length.