No abstract

In order to increase the brightness, the relative dielectric constant of the dielectric layer inserted between rear electrode and phosphor layer should be high. We manufactured BaTiO 3 -PVDF 0-3 type composite film for the application of the dielectric layer in the high brightness inorganic electro-luminescence (EL) device. The pastes for the BaTiO 3 -PVDF composite film were made with various mixing ratio by using 3-roll milling mixer. The pastes were coated on the phosphor layer by screen-printing method. The phosphor layer was also coated on a substrate by using the same screen-printing system. The substrate is an indium tin oxide (ITO) film deposited on PET (polyethylene terephthalate) polymer film. The others of rear electrode and insulating layer were also coated by the screen-printing method. Both the relative dielectric constant and the brightness of the fabricated EL device were increased with increasing the weight percent of BaTiO 3 dielectric material in the composite films. The brightness was also increased with decreasing the thickness of the dielectric layer. The brightness was enough to be applied to the backlight of the keypad in mobile phones.