Abstract: A gas discharge display screen with a self-scanning function is described herein. All the electrodes are positioned coplanary on a single surface of a rear insulating plate. First and second pluralities of parallel electrodes connected respectively independently accomplish respectively the scanning and displaying functions. A third plurality of parallel electrodes perpendicular to the first and second pluralities of electrodes cooperates with a particular electrode for preionizing the first gas cells of the matrix screen lines.

Abstract: A writing head for reproducing a line on an image upon a light sensitive surface from a periodically pulsed signal, the timing or period of the pulses representing the position on the line at which writing is to take place. The writing head comprises a series of cathodes and two anodes in contact with a gas at low pressure. The two anodes are in the form of parallel, metallic adjacent strips extending transversely of the cathodes. One of the anodes is continuous and opaque while the other anode is formed with holes for allowing the light produced by gas discharge to fall on a photo-sensitive carrier. The cathodes may be disposed in a common plane and parallel to each other; they may also be connected in a cyclic array to a plurality of bus bars and successively energized.