US 5,549,843 A · Annealed alkaline earth metal fluorohalide storage phosphor, preparation method, and radiation image storage panel

Abstract

A method, a storage phosphor prepared by the method, and a storage panel. In the method, a precursor mixture is fired, at a temperature between 700.degree. C. and the melting point of the phosphor, to produce an intermediate product. The precursor mixture comprises a combination of species characterized by the relationship: MFX.sub.1-x I.sub.z.uM.sup.a X.sup.a :yA:eQ wherein M is selected from Mg, Ca, Sr and Ba; X is selected from Cl and Br; M.sup.a is selected from Na, K, Rb and Cs; X.sup.a is selected from F, Cl, Br and I; A is selected from Eu, Ce, Sm, and Tb; Q is metal oxide; and 0<z.ltoreq.1; 0<u<1; 0<y.ltoreq.0.1; and 0<e<0.1. The intermediate product is then annealed in a slightly oxidizing atmosphere, at a temperature, which is lower than said temperature of firing and between about 400.degree. C. and about 800.degree. C., for a time sufficient to reduce the erase fraction of the resulting phosphor relative to the same phosphor produced by firing in the same manner, but not annealing.

Claims22

Dependent claims

A method for preparing a storage phosphor comprising the steps of:

firing, at a temperature greater than 700.degree. C., a combination of species including species characterized by the relationship:
MFX.sub.1-z I.sub.z.uM.sup.a X.sup.a :yA:eQ
wherein
M is selected from Mg, Ca, Sr and Ba, and combinations thereof;
X is selected from Cl and Br, and combinations thereof;
M.sup.a is selected from Na, K, Rb and Cs, and combinations thereof;
X.sup.a is selected from F, Cl, Br and I, and combinations thereof;
A is selected from Eu, Ce, Sin, and Tb, and combinations thereof;
Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2, and combinations thereof;
and
0<z<1;
0<u<1;
0<y<0.1;
and
0<e<0.1
to produce an intermediate product;
and
annealing said intermediate product in a slightly oxidizing atmosphere and at a temperature lower than said temperature of said firing and between about 400.degree. C. and about 800.degree. C., for a time sufficient to reduce the erase fraction (EF) relative to the same phosphor produced without said annealing.

15 more elements

A method for preparing a storage phosphor comprising the steps of:

firing, in an atmosphere of inert gas and from 0 to about 200 parts per million of oxygen, at a temperature from about 750.degree. C. to about 950.degree. C., combination of species is characterized by the relationship:
(Ba.sub.1-a-b-c Mg.sub.a Ca.sub.b Sr.sub.c)FX.sub.1-z I.sub.z.rM.sup.a X.sup.a :yA:eQ:tD:dE
wherein
X is selected from the group consisting of Cl and Br, and combinations thereof;
M.sup.a is selected from the group consisting of Na, K, Rb and Cs, and combinations thereof;
X.sup.a is selected from the group consisting of F, Cl, and Br, and combinations thereof;
A is selected from the group consisting of Eu, Ce, Sm, and Tb, and combinations thereof;
Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2, and combinations thereof;
D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni, and combinations thereof;
E is an oxosulfur reducing agent selected from the group consisting of compounds and salts having a moiety or ion of the general formula S.sub.j O.sub.k, where j and k are positive integers such that 0.25<j/k<1.0, and combinations thereof;
a+b+c is from 0 to 0.4;
z is from 1.times.10.sup.-2 to 1;
r is from 1.times.10.sup.-6 to 0.1;
y is from 1.times.10.sup.-4 to 0.1;
c is from 1.times.10.sup.-5 to 0.1;
t is from 0 to 10.sup.-2 ;
and
d is from 0 to 0.020
to produce an intermediate product;
and
annealing said intermediate product, in an atmosphere of inert gas and from about 10 to about 200 parts per million of oxygen, at a temperature lower than said temperature of said firing and between about 400.degree. C. and about 800.degree. C., for a time sufficient to deplete iodide relative to the iodide concentration of said combination of species.

18 more elements

An annealed storage phosphor consisting essentially of oxygen and a combination of species characterized by the relationship:

(Ba.sub.1-a-b-c Mg.sub.a Ca.sub.b Sr.sub.c)FX.sub.1-z I.sub.z-2x.rM.sup.a X.sub.a :yA:eQ:tD:dS
wherein
X is selected from the group consisting of Cl and Br, and combinations thereof;
M.sup.a is selected from the group consisting of Na, K, Rb and Cs, and combinations thereof;
X.sup.a is selected from the group consisting of F, Cl, and Br, and combinations thereof;
A is selected from the group consisting of Eu, Ce, Sin, and Tb, and combinations thereof;
Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2, and combinations thereof;
D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni, and combinations thereof;
a+b+c is from 0 to 0.4;
z is from 1.times.10.sup.-2 to 1;
x is from 1.times.10.sup.-4 to 1.times.10.sup.-2 ;
r is from 0 to 0.1;
y is from 1.times.10.sup.-4 to 0.1;
e is from 1.times.10.sup.-5 to 0.1;
t is from 0 to 10.sup.-2 ;
and
d' is from 0 to 0.020.

14 more elements

A storage phosphor consisting essentially of a combination of species characterized by the relationship:

(Ba.sub.1-a-b-c Mg.sub.a Ca.sub.b Sr.sub.c)FX.sub.1-z I.sub.z-2x O.sub.x.rM.sup.a X.sup.a :yA:eQ:tD:d'S
wherein
X is selected from the group consisting of Cl and Br, and combinations thereof;
M.sup.a is selected from the group consisting of Na, K, Rb and Cs, and combinations thereof;
X.sup.a is selected from the group consisting of F, Cl, and Br, and combinations thereof;
A is selected from the group consisting of Eu, Ce, Sm, and Tb, and combinations thereof;
Q is selected from the group consisting of BcO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2, and combinations thereof;
D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni, and combinations thereof;
a+b+c is from 0 to 0.4;
z is from 1.times.10.sup.-2 to 1;
x is from 1.times.10.sup.-4 to 1.times.10.sup.-2 ;
r is from 0 to 0.1;
y is from 1.times.10.sup.-4 to 0.1;
e is from 0 to 0.1;
t is from 0 to 10.sup.-2 ;
and
d is from 0 to 0.020.