| 摘要 |
PURPOSE: To improve the life and luminous efficiency of a Y2SiO5:Ce fluorescent substance performing blue luminescence and capable of being used for an FED (field emission display). CONSTITUTION: In an A2SiO5:B (wherein A is Y or Gd; and B is Ce or Tb) fluorescent substance, an elemental composition ratio (A+B)/Si on the surface is set to be 1.5-2.5. For example, coprecipitated (Y, Ce)2O3 (wherein a ratio Ce/Y is fixed in such a way as to be 1 atom.%) with, an oxalate and SiO2 fine powder are used, charge stock wherein a composition ratio of SiO2 to (Y, Ce)2O3 is set to be 10-110% as a ratio between raw materials is satisfactorily compounded and is thrown into an inner crucible of an alumina double crucible, graphite is filled between the inner and outer crucibles and synthesis is carried out in a kiln. The Y2SiO5:Ce fluorescent substance is obtained by holding the temperature at 1,450deg.C for 2 hours. The luminous efficiency of the fluorescent substance layer is measured by making a FED made as a model using the fluorescent substance emit light under conditions that an anodic voltage is 600 V, input power is 30 Wp-p and a duty ratio is 1/240. The charge of SiO2 should be 40-70%, preferably 50-60%. |
