Kabushiki Kaisha Toshiba

Yohe Shimizu

Hirofumi Takemura

Tsuyoshi Oyaizu

Takeshi Takahara

Mitsuhiro Oikawa

Akira Mikami

Satoshi Sugano

Hiroyasu Yashima

A red emitting phosphor comprises a yttrium oxysulfide phosphor as a base material. A red emitting phosphor of medium particle size type has such a particle size distribution that a content of a component of a particle diameter of less than 4.0 &mgr;m is 15% or less, that of a component of a particle diameter of 4.0 &mgr;m or more and less than 8.0 &mgr;m is 75% or more, and that of a component of a particle diameter of 8.0 &mgr;m or more is 10% or less. A red emitting phosphor of larger particle size type has such a particle size distribution that the content of a component of a particle diameter of less than 5.04 &mgr;m is 20% or less, that of a component of a particle diameter of 5.04 &mgr;m or more and less than 10.079 &mgr;m is 70% or more, and that of a component of a particle diameter of 10.079 &mgr;m or more is 10% or less. Phosphor layers employing these red emitting phosphors are excellent in denseness. Accordingly, a cathode ray tube of high contrast and high quality can be provided.

Red emitting phosphor for cathode ray tube

An electroluminescent phosphor comprises zinc sulfide as a phosphor base material, at least one kind selected from copper and manganese as an activator, and at least one kind selected from chlorine, bromine, iodine, and aluminum as a coactivator. The content of alkaline earth metal elements in the electroluminescent phosphor is 0.05% by weight or less. In addition, the electroluminescent phosphor includes cesium in the range of 0.0001% by weight or more and 0.01% by weight or less. Such an electroluminescent phosphor has excellent brightness and life. An electroluminescent element comprises a phosphor layer in which an electroluminescent phosphor is dispersed in a dielectric. The electroluminescent phosphor includes reduced amount of alkaline earth metal elements and a slight amount of cesium.

Electroluminescent phosphor and electroluminescent element using the same

Growing community of inventors

Shizuoka-ken, Japan

Yohe Shimizu