| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fluorescent substance imparted electric conductivity without impairing luminous efficiency by reducing at a specified condition. SOLUTION: This substance is obtained by following steps; 4 kg raw material (Y0.965Eu0.035)2O3 and 14.0 kg flux NaCl are weighed and mixed. The mixture is filled in a melting pot and baked at 1,400 deg.C for 6 h. The resultant sample is put into pure water, agitated, decanted and washed out the flux with water. The fluorescent Y2O3:Eu is obtained by dehydrating and drying the resultant at 110 deg.C and sieved. A part of the sample is remained as a reference fluorescent substance. An A2O3-x:Re fluorescent substance (A is a rare earth element; Re is one or more element selected from Eu, Tb, Er, Tm, Dy, Ho, Nd, Pr, Sm or Ce) (reduced fluorescent) is obtained by filling 400 g above mentioned fluorescent substance in a melting pot and annealing in a carbonic reductive atmosphere at 900-1,300 deg.C for 1-14 h. Each of the obtained fluorescent substances is mounted on an anode of each difference fluorescent tube and the luminous state is compared. The relationship between amount of oxygen defect and emission initiation voltage shows that the more defect amount, the lower initiation voltage and so charge up of the tube surface is solved and resistance of the luminous substance is decreased.
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