Abstract: An image display comprises: a display device having an image output surface at which an image is displayed as a spaced array of pixel elements; an image guide (20) coupled to the image output surface of the display device and comprising a plurality of light transmission guides (80) each having an input end and an output end, the input ends of the light transmission guides being arranged relative to one another so that groups of one or more light transmission guides receive light from respective groups of one or for a cluster comprising at least a subset of the light transmission guides (80): at the outer periphery of the cluster, the input ends of the light transmission guides are constrained against expansion by a frame formed of a material having thermal expansion properties which are substantially similar to the thermal expansion properties of the image output surface.

Abstract: A large-area collimated beam of radiation is formed by re-directing a beam of small projected area off one or two orthogonal surfaces which are faceted or have a non-specular reflection angle and which spatially distribute the incoming beam across their surface area. Preferably there are two expansion stages, one for each dimension. If the input beam is linearly polarised then the output beam will also be polarised. The polarisation will undergo a rotation through 90 degrees. The beam expander is compact and suitable for use in liquid-crystal flat-panel displays.