PURPOSE: To prevent irregularity of electroluminance by applying supersonic vibration to a highly dielectric organic binder solution so as to lower the viscosity before dispersing powder of a phosphor.
CONSTITUTION: A highly dielectric organic binder solution B is prepared by dissolving an organic high dielectric substance in a suitable organic solvent. Application of supersonic vibration to the highly dielectric organic binder solution B to lower the viscosity is carried out by a method wherein the highly dielectric organic binder solution B is contained in a container 21 made of such as stainless steel and a supersonic vibrator 22 is immersed in the solution. The container 21 is cooled by water W contained in a water tub 23. By this method, a phosphor slurry becomes a substance of high concentration in spite of low viscosity and irregularity of luminance can be suppressed.
MINAMI TETSUO
AOKI NOBUHIKO
