Abstract: 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.