PURPOSE: To provide the titled green light-emitting phosphor which does not cause brightness saturation even in a highly excited state, exhibits high brightness, does not have a problem of quenching by temperature and suffer little variation in brightness caused by variation in the composition, consisting of Y3AlxGa5-x)12:Tb which has a composition satisfying specified conditions.
CONSTITUTION: Y2O3, Al2O3, Ga2O3 and Tb4O7 are mixed together. The mixture is fired at 1,500°C for 2hr to obtain a green light-emitting phosphor of the Y3Al5Ga5-xO12:Tb having a composition present in an inside region which is surrounded by a closed curve and does not include the boundary of the curve, said closed curve being obtd. by connecting the points A to H to each other in order under conditions of exciting voltage of 30KV and current density of 90μA/cm3, each of A to H being the values of the molar ratio of Al/Ga and mol% of Tb/(Y+Tb) given in the table. In the Fugure, the abscissa represents the molar ratio of Al/Ga, the ordinate represents mol%(=Tb concn.) of Tb/(Y+Tb), the point S represents Y3Al5O12:Tb which represents the point of the reference value 100 of the brightness of Tb concn. of 5mol%, broken lines represent lines of equal brightness, and the figure of each line represents relative brightness.
ABE TOMOHIKO
TAMURA MASAYOSHI
| JPS56125479A | 1981-10-01 |