Blue Emitting Phosphors for Projection Cathode Ray Tubes: and

Abstract

Substitution of yttrium or gadolinium for lanthanum in leads to efficient blue‐emitting and phosphors. Energy efficiencies under cathode ray excitation of 11% have been realized for phosphors with emission colors comparable with that of . The optimum preparation procedure consists in firing cerium‐activated oxalates in a flowing atmosphere containing bromine at 1100°C. Thermal quenching and linearity of the luminescence have been investigated. The hygroscopicity should pose no problems in screen manufacturing. Application of and especially could lead to a significant increase in the brightness of projection television systems.