LIFETIME ANALYIS OF SATURATED PHOSPHORS

摘要

It is of interest to understand the saturation characteristics of FED phosphors under FED operating conditions so as to derive a more complete picture of the material characteristics influencing a phosphor's level of resistance to saturation. Ground state depletion is well understood and can be minimized through the use of fast decay phosphors such as the SrGa_2S_4:Eu~(2+) and SrGa_2S_4:Ce~(3+). However, saturation by higher order energy transfer processes are possible and can provide an explanation for the observed saturation in fast as well as slow decay phosphors. These second order effects have been observed and analyzed for phosphors such as Y_2SiO_5:Tb, YAGAG:Tb, LaOBr:Tb, TbF_3:Tb, and ZnS:Ag,Al,. Although using fast decaying phosphors increases the number of available ground states under high power density excitation, the higher order saturation effects are of significant interest because they provide an additional limitation to performance. This study intends to lay the groundwork for examining and distinguishing the saturation mechanisms occurring in fast activator phosphors.