Abstract: A module, for a data display panel, comprising a number of elements, each separately controllable to be selectively illuminated or extinguished so as to display any one of a plurality of symbols. The transmission of light to each of the elements of the module is controlled by an individual occulting or blanking member. Each element comprises an optical light transmission system having an input end with a source surface, the illumination of which is controlled by its individual blanking member and an output end with an image surface which reproduces the state of illumination of the source surface. The image surfaces are preferably contiguous with the source surfaces spaced apart. Each image surface may have a different area to its associated source surface and such surfaces may occupy arbitrary relative positions, i.e. not necessarily being directly opposed to one another.