@misc{oai:niigata-u.repo.nii.ac.jp:00004735,
 author = {Komeno, Akira},
 month = {Mar},
 note = {Phosphor materials emit various colors of lights after absorption of excitation energy such as X ray, ultraviolet light and visible light. Phosphors are important materials for displays and lighting. The roles of fluorescent lamps and displays for use as light source and color signboards have become increasingly important in daily life. In white fluorescent lamps, ultraviolet (UV: 254nm) irradiation from mercury vapor is converted into visible light by several kinds of phosphors. A salient concern is the possibility of environmental pollution caused by the mercury in fluorescent lamps. The EU adopted the Waste Electrical and Electronic Equipment (WEEE) and Restrictions on the use of certain Hazardous Substances (RoHS) in electrical and electronic equipment on February 13, 2003. Both WEEE and RoHS restrict the use of certain hazardous substances in electrical and electronic equipment. Consequently, researchers have developed new types of phosphors to provide mercury-free lighting. VUV fluorescence lamps and white LEDs are anticipated as the candidates for use in mercury-free lamps. Selection of crystal structures and composition elements is important for research into phosphors. Increase of emission ions is very effective for obtaining high brightness. However, that emission is often quenched over a critical concentration. Concentration quenching results from migration of excitation energy among the emission ions; it is related to the crystal structure. Longer separation and lower dimensional arrangements of emission ions control concentration quenching. [1] Phosphors are exposed to high-energy excitation illumination. For that reason, host materials must be durable. A host material that contains high-covalent-bond elements is anticipated to offer excellent durability. For this research, alkaline earth silicates were chosen as low-dimensional structure hosts with high covalently bonded Si-O. Synthesis, crystal structure analysis, and the luminosity properties of phosphors were examined from viewpoints of luminescence properties and crystallography. On the other hand, long persistent phosphors are materials that absorb visible light and emit afterglow. Previously, alkaline earth sulfides and zinc sulfides doped radioactive materials were used as the long persistent phosphors. However, sulfides tend to degrade with exposure to atmospheric moisture. Although long persistent phosphors with radioisotope give long afterglows, such radioactive materials can strongly affect the environment. Recently, long-persistent phosphors, alkali earth aluminates (SrAl2O4 : Eu2+,Dy3+), without radioisotopes have attracted attention because they show more persistent properties than do conventional zinc sulphide phosphors (e.g. ZnS: Cu) [1]. Although these phosphors show high-intensity emission, their luminescent color is restricted within a narrow range around green. Green emitting materials are used for luminous paints because of their high visibility in the dark. However, the restricted narrow range around hinders its application to other use. Persistent phosphors will be applicable in the many fields such as full color signboards and lighting devices that require no energy supply if multicolored emission phosphor was synthesized. Therefore, the high emitting light phosphors aside from green are desired. Chapter 1 presents discussion of Ba2MgSi2O7: Eu2+ properties as the VUV excitation phosphor, white-LED phosphor and mineral based phosphors. Properties of a white LED phosphor, Ba9Sc2Si9O24: Eu2+, are reported in Chapter 2. New long-persistence phosphors, Ca0.5Sr1.5Al2SiO7: Ce3+, Tb3+ and BaMg2Si2O7: Eu2+,Mn2+ are discussed in Chapter 3., 新大院博（工）甲第218号, 新大院博（工）甲第218号},
 title = {The development of the phosphors　for the lighting},
 year = {2006}
}