Application of screen‐printed rare earth oxide protective film to alternating‐current plasma display panels

Abstract

AbstractScreen‐printed protective film of rare earth oxides (La2O3, Gd2O3, Dy2O3, Y2O3, and Yb2O3) was applied to ac‐plasma display panels. Screen‐printed rare earth protective films have higher luminous efficiencies than a sputtered MgO protective film. However, it is difficult to obtain a low firing voltage (Vf) from screen‐printed rare earth oxide protective films.Only the La2O3 protective film has a lower firing voltage than the sputtered MgO protective film. Gd2O3 has the lowest sustaining voltage (VS) which is 54 V lower than that of the sputtered MgO protective film. Since rare earth oxide powders with high crystallinity exhibit superior discharge characteristics, it is necessary to improve the crystallinity of the powders. In order to obtain a high luminous efficiency, it is necessary to have a low discharge current. Both Y2O3 and La2O3 have a high current‐limiting effect. The current‐limiting effect is related closely to cell resistance. Since Dy2O3 has a low cell resistance, its current‐limiting effect is low. Gd2O3 has the highest luminance per unit discharge current. If it is possible to reduce the discharge current of Gd2O3 further, it is possible to obtain a higher luminous efficiency. Every screen‐printed rare earth oxide film has an excellent protective effect. However, from the viewpoint of low discharge voltage and high luminous efficiency, La2O3 and Gd2O3 are superior to all other rare earth oxides due to their low discharge voltage and high luminous efficiency.