A Review of Depreciative Color Center Phenomena in Lamp Phosphors

Publisher Website
Google Scholar
Abstract
A review of the role played by color centers in the deterioration of lumen output of lamp phosphors with special attention to the halophosphates is presented. Color center dynamics in halophosphates result in a rapid degradation in phosphor brightness within minutes after the beginning of lamp life. An examination of the extent and rapidity of this effect is reviewed. Unirradiated spectral characteristics of halophosphates are dependent on growth stoichiometry. Radiatively induced spectral absorptions are dependent on the relative intensity of Hg u.v. components and crystal deformation and show thermal and optical bleaching effects. A dynamical model of color centers in halophosphates is extracted from the literature that explains the essential experimental dependencies. Related color center effects in phosphors including defect generation considerations for long‐term brightness deterioration are also presented.