As a company producing ink-jet equipment for the soluble process OLED, Seiko Epson has already developed the ink-jet head which could realize up to 360ppi by arranging the 180ppi nozzles in 2 rows. Given that the resolution of the evaporation method RGB OLED is still in the 260ppi as a real RGB, it is a significantly useful technology in the development of high-resolution display.