Nemoto & Company, Ltd.

Yasumitsu Aoki

Nobuyoshi Takeuchi

Takashi Matsuzawa

Yoshihiko Murayama

A phosphorescent phosphor comprising a matrix expressed by M.sub.1-x Al.sub.2 O.sub.4-x (except X=0) in which M is at least one metal element selected from a group consisting of calcium, strontium and barium. X is in a range -0.33.ltoreq..times..ltoreq.0.60 (except x=0). Europium is doped to said matrix as an activator and at least one element selected from a group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium is doped to said matrix as a co-activator. Magnesium is doped to M.

Phosphorescent phosphor

A phosphorescent phosphor according to the present invention includes a matrix expressed by MAl.sub.2 O.sub.4 in which M is at least one metal element selected from a group consisting of calcium, strontium and barium. Alternatively, a phosphorescent phosphor according to the present invention includes a matrix expressed by MAl.sub.2 O.sub.4 in which M is plural metal elements which are composed of magnesium and at least one metal element selected from a group consisting of calcium, strontium and barium and europium is added as an activator, further, co-activator is added.

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Tokyo, Japan

Yasumitsu Aoki