Process for producing fluorescent substance and fluorescent substance produced thereby

Abstract

The present invention provides a fluorescent substance excellent both in quantum efficiency and in temperature characteristics, and also provides a process for producing the fluorescent substance. This fluorescent substance is an oxynitride phosphor having a low paramagnetic defect density and comprising aluminum, silicon, either or both of oxygen and nitrogen, and a metal element M, provided that the metal element M is partly replaced with an emission center element R. That phosphor can be produced by the steps of: subjecting a mixture of starting materials to heat treatment under a nitrogen atmosphere so as to obtain an intermediate fired product, and then further subjecting the intermediate fired product to heat treatment under an atmosphere of nitrogen-hydrogen mixed gas.

1 - 11 . (canceled) 
     
     
         12 . An oxynitride phosphor comprising aluminum, silicon, either or both of oxygen and nitrogen, and a metal element M selected from the group consisting of IA group elements, IIA group elements, IIIA group elements other than aluminum, IIIB group elements, rare earth elements and IVA group elements other than silicon, provided that said metal element M is partly replaced with an emission center element R selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, T 1 , Pb, Bi and Fe;
 which has the same crystal structure as Sr 3 Al 3 Si 13 O 2 N 21 ;   whose paramagnetic defect density detected at g=2.002 in electron spin resonance measurement is less than 2×10 14  spins/g; and   which is represented by the following formula (1):
   (M 1-x1 R x1 ) 3-y1 Si 13-z Al 3+z O 2+u N 21-w   (1).
 
   in which M and R are individually the same elements as described above; and x1, y1, z, u and w are numbers satisfying the conditions of 0<x1≦1, −0.1≦y1≦0.15, −1≦z≦1, and −1<u−w≦1, respectively; and   which emits luminescence having a peak in the wavelength range of 490 to 580 nm when excited by light in the wavelength range of 250 to 500 nm.   
     
     
         13 . The oxynitride phosphor of  claim 12 , wherein the metal element M is a IA group element. 
     
     
         14 . The oxynitride phosphor of  claim 12 , wherein the metal element M is A IIA group element. 
     
     
         15 . The oxynitride phosphor of  claim 12 , wherein the metal element M is IIIA group element other than aluminum 
     
     
         16 . The oxynitride phosphor of  claim 12 , wherein the metal element M is IIIB group element. 
     
     
         17 . The oxynitride phosphor of  claim 12 , wherein the metal element M is rare earth element. 
     
     
         18 . The oxynitride phosphor of  claim 12 , wherein the metal element M is a IVA group element other than silicon 
     
     
         19 . The oxynitride phosphor of  claim 12 , wherein R is Eu. 
     
     
         20 . The oxynitride phosphor of  claim 12 , wherein R is Mn. 
     
     
         21 . An oxynitride phosphor comprising aluminum, silicon, either or both of oxygen and nitrogen, and a metal element M selected from the group consisting of IA group elements, IIA group elements, IIIA group elements other than aluminum, IIIB group elements, rare earth elements and IVA group elements other than silicon, provided that said metal element M is partly replaced with an emission center element R selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe;
 which has the same crystal structure as Sr 2 Al 3 Si 7 O 2 N 13 ; and   whose paramagnetic defect density detected at g=2.002 in electron spin resonance measurement is less than 2×10 14  spins/g; and   which is represented by the following formula (2):
   (M 1-x2 R x2 ) a Si b AlO c N d   (2)
 
   in which M and R are individually the same elements described above; and x2, a, b, c and d are numbers satisfying the conditions of 0<x2<0.4, 0.65<a<0.70, 2<b<3, 0.3<c<0.6 and 4<d<5, respectively; and   which emits luminescence having a peak in the wavelength range of 570 to 650 nm when excited by light in the wavelength range of 250 to 500 nm.   
     
     
         22 . The oxynitride phosphor of  claim 21 , wherein the metal element M is a IA group element. 
     
     
         23 . The oxynitride phosphor of  claim 21 , wherein the metal element M is A IIA group element. 
     
     
         24 . The oxynitride phosphor of  claim 21 , wherein the metal element M is IIIA group element other than aluminum 
     
     
         25 . The oxynitride phosphor of  claim 21 , wherein the metal element M is IIIB group element. 
     
     
         26 . The oxynitride phosphor of  claim 21 , wherein the metal element M is rare earth element. 
     
     
         27 . The oxynitride phosphor of  claim 21 , wherein the metal element M is a IVA group element other than silicon 
     
     
         28 . The oxynitride phosphor of  claim 21 , wherein R is Eu. 
     
     
         29 . The oxynitride phosphor of  claim 21 , wherein R is Mn.