abstract |
Luminous substances have formulae: (1-x-y)L2O2S.xEu2O2S.yPr2O2S and (1-x-y-z)L2O2S.xEu2O2S.yPr2O2S.ZTb2O2S, where L is lanthamide, esp. Gd or La; x = 0.03-0.05; y = 2x10-6 - 1x10-4, esp. 3.0x10-6 - 1.5x10-5, z = 2x10-6 4.0x10-5, esp. 7.0x10-6 to 2.0x10-5. Degree of luminosity is raised by the addition of Praseodymium and also Terbium if necessary. |