Abstract: An illuminated information display apparatus comprising: a rectangular frame member having top, bottom and side walls defining an elongated housing having at least one open face; grooves provided in opposing marginal edges of the top and bottom walls of the housing and extending the length thereof; a plurality of interlocking indicia bearing plate members sized to be slidably received in the opposed grooves, the plate members having light transmitting and blocking portions thereon; a source of illumination mounted interiorly of the housing; and a photoelectric cell connected to the source of illumination and exposed to ambient light conditions for selectively activating and deactivating the source of illumination at predetermined states of ambient light.