FLUORESCENT SUBSTANCE AND FLUORESCENT DISPLAY TUBE

摘要

PROBLEM TO BE SOLVED: To provide a yellow light emitting fluorescent substance useful for a fluorescent display tube excluding cadmium. SOLUTION: The addition amount of Eu in a conventional red light emitting fluorescent substance of La2O2S:E is 0.2-5 mol.%. The addition amount of Eu in this fluorescent substance is 0.001-0.1 mol.% per 1 mole of a base. A life property of the fluorescent substance is tested by packaging it in a low-voltage driven fluorescent display tube. Yellow light emission of good color purity is obtained and the excellent life property is clarified. A square mark in the figure 2 shows brightness persistence after continuous lighting for 1,000 hrs. The brightness persistence of 75-105% is ensured in Eu concentration of 0.1-0.001 mol.% compared to that of 50% of Eu in conventional fluorescent substance of 1 mol.% Eu concentration.