| 摘要 |
A phosphorescent material has an excellent life time characteristic when it is applied to display device such as a fluorescent display device and includes a body portion composed of alkali metal and an oxide, and a protective coat formed over a surface of the body portion. The protective coat is composed of an oxide containing at least one element selected from the group consisting of Al, Ti, Si, Zn, Sn, Bi, Sb, Ce, Y, Ta, Gd, Ru and Ga. |
