Abstract: This relates to a back-lightable display panel for displaying alphanumeric characters and graphics comprising a plurality of mechanically movable elements, each having a dark translucent face and a bright translucent face which are moved from one to the other face interchangeably by a series of electromechanical driving elements; and diffusion means interposed between the source of light and the display panel for scattering the light falling on the display panel from the source, whereby shadows cast by the electromechanical driving elements on the display panel are substantially invisible from the front of the display. The sign comprises a series of rectangular blocks which may be mounted to form a mosaic of any desired size.