Abstract: There is disclosed a gas discharge device containing electrode arrays, an ionizable gaseous medium, and a phosphor excited at least in part by radiation from the gas discharge of the device, the life of the phosphor being increased by the application of a phosphor overcoat which is at least partially transmissive to excitation radiation from the gas discharge. The phosphor overcoat is typically selected from alkali and alkaline earth fluorides. In one embodiment, the gaseous medium comprises at least one rare gas selected from neon or argon and at least one other rare gas selected from argon, xenon, krypton. The gas discharge device is preferably of the display/memory type wherein electrical charges are stored on opposing dielectric surfaces, the phosphor and phosphor overcoat being positioned on the dielectric surfaces near the gas discharge.