Abstract: An optical display device for symbols having a body of material, having an index of refraction, which is greater than 1, and at least one symbol, character or the like, which is in optical contrast with the background, characterized by the body containing fluorescent particles, having a surface which is at least partially reflective, and each of the characters or symbols or the like being formed by appropriately shaped output coupling zones in the body. Preferably, the output coupling zones are formed by indentations on a rear surface of the body when taken in the direction of observation. Preferably, the device includes a light valve for at least some of the output coupling zones so that both static symbols and controllable symbols may be displayed.