A display panel includes a first scanning band, a second scanning band, and a third scanning band positioned between the first scanning band and the second scanning band, and each scanning band includes a plurality of parallel scanning lines. A linear abrasive brush member comprising: an embedded core material ; a rod-shaped substrate part having opposite long-narrow upper and bottom faces; and a plurality of filament parts present on the upper surface along the longitudinal direction; and the substrate part and the filament parts being integrally molded from a resin composition. The composition can be included in a cavity of a warhead. The p-type gallium nitride based semiconductor layer 37 includes, for example, a p-type AlGaN electron block layer and a p-type GaN contact layer.