DE2621538

A first glass substrate supports a plurality of electrodes arranged in concentric circles. A second glass substrate supports a plurality of shift electrodes arranged radially. The substrates are positioned face to face with a specified space between them filled with an ionizable gas. The radially arranged shift electrodes are periodically connected to common buses each connected to a corresponding one of a plurality of shift driver circuits equal in number to the buses. At least one of the shift electrodes is selectively connected to a write driver circuit and to one of the shift driver circuits. When the one of the shift electrodes is energized by a signal from the write driver circuit, discharge spots are generated at the intersection of the one of the shift electrodes and the concentrically arranged electrodes. The discharge spots are endlessly shifted in clockwise or counterclockwise direction along the concentrically arranged electrodes through the switching of operating voltages applied sequentially to the shift electrodes from the shift driver circuits via the buses.