PHOTOLUMINESCENT PHOSPHOR WITH OVERLONG-DURATION AFTERGLOW Russian patent published in 2002 - IPC

FIELD: luminophors. SUBSTANCE: photoluminescent phosphor, which can be used for emergency and off-line lighting systems, special- destination clothing, astronomic object simulation and highway warning devices, contains II-group element oxides (MeO), alumina, IV-group element oxides (MeO₂), and silica at molar ratio 3:1:2:1, respectively, and, in addition, one rare- earth element. Molar ratio MsO/CaO/SrO ranges from 1:4:5 to 1:2:7. As rare-earth element, photoluminescent phosphor contains at least one element selected from Eu, Sm, and Yb and at least one element selected from Y, Nd, Ce, Er, Ho, Yb, and Gd at atomic ratio of indicated groups of elements between 1: 1 and 3: 1. Photoluminescent phosphor is depicted by formula Ca_3-yAl_2-xSi•Zr₂O₁₂•Eu_yY_x, in which x=0.005-0.01, y=0.01-0.2. Its brightness during 60 min after excitement considerably rises and slowly drops during 12 h. Maximum of thermoluminescence is observed within a temperature range of 350-400 K. EFFECT: enhanced luminescence characteristics and increased hydrolytic stability. 3 cl, 1 tbl, 6 ex