The relationships between lattice orientation of the electron-beam evaporated MgO layer used as protecting layer for ac plasma displays (ac-PDPs) and the discharge characteristics of color ac-PDPs were investigated by the measurements of ion-induced secondary electron emission. It is proved that values of γi for MgO are large in the order of (220) orientation, (200) orientation, and (111) orientation, that is, γi(220) > γi(200) > γi(111). The values of φ for different lattice orientation are obtained by the measurements of thermionic emission and photo emission. The aging measurements for testing panels with the different lattice orientation of MgO layer revealed that performance of those panels are excellent in the order of (220), (200), and (111). In particular, luminance and luminous efficiency become larger in the order of (220), (200), and (111). It is pointed out that the degree of longevity, sustaining voltage, and memory margin for ac-PDPs with protecting materials as MgO are estimated by the measurements of γi.

In order to improve luminance and luminous efficiency of color ac plasma displays (PDPs), absorption characteristics of ultraviolet rays were investigated for dielectric materials from a viewpoint of protecting layer of ac PDPs. The double protecting layer of MgF2 and MgO is clarified to be excellent property to improve the optical performance of color ac PDPs. The double protecting layer of MgF2 and MgO was applied to the barrier-rib electrode color ac PDPs and resulted in high luminance and luminous efficiency of 1030 cd/m2 and 1.0lm/W, respectively.