RED-EMITTING PHOSPHOR FOR CATHODE-RAY TUBE, AND CATHODE- RAY TUBE

摘要

PROBLEM TO BE SOLVED: To improve the fineness of a fluorescent film formed by using a red- emitting phosphor for cathode ray tubes and thus enhance the luminance of the fluorescent film. SOLUTION: This red-emitting phosphor for cathode-ray tubes having a phosphor powder comprises yttrium oxysulfide as a phosphor matrix and has such particle size distribution that the medium-particle-size red-emitting phosphor consists of a 15% or lower fraction having a particle size larger than 4.0μm, a 75% or higher fraction having a particle size of 4.0μm or larger and smaller than 8.0μm, and a 10% or lower fraction having a particle size of 8.0μm or larger and that the large-particle-size red-emitting phosphor consists of a 20% or less fraction having a particle size smaller than 5.04μm, a 70% or more fraction having a particle size of 5.04μm or larger and smaller than 10.079μm, and a 10% or less fraction having a particle size of 10.079μm or larger.