An insulation layer covering segment layers and a plurality of row electrodes arranged on a first substrate has, on its surface, first projections and second projections. The first projections have a shape and a height corresponding to those of the row electrode, and contacts partitions disposed on a second substrate. The second projections have a shape and a height corresponding to those of the segment layer. The partitions and the second projections constitute discharge barriers between columns, which prevents discharge interference from occurring between cells along the row electrodes.