US 5,885,483 A · Long afterglow phosphor and a process for the preparing thereof

Abstract

The invention relates to a long afterglow phosphor and a process for preparing the phosphor, characterized in that the phosphor comprises the sinter expressed by a general formula MO.multidot.(n-x)a Al.sub.2 O.sub.3.sup..alpha. .div.(1-a)Al.sub.2 O.sub.3.sup..gamma. !.multidot.B.sub.2 O.sub.3 : R, where, M represents and alkaline earth metal, R represents a rare earth element, 0.5<a.ltoreq.0.99, 0.001.ltoreq.x.ltoreq.0.35, and 1.ltoreq.n.ltoreq.8, and a part of M may be replaced with at least one alkaline earth metal selected from Mg, Ca and Ba. R may also use other rare earth elements in addition to Eu as additional activators. The process for preparing the long afterglow phosphor of the present invention comprises several steps, wherein the sintering temperature needs to be 800.degree.-1200.degree. C.

Claims10

Dependent claims

A long afterglow phosphor comprising a sinter represented by a general composition:

MO.multidot.(n-x){aAl.sub.2 O.sub.3.sup..alpha. +(1-a)Al.sub.2 O.sub.3.sup..gamma. }.multidot.xB.sub.2 O.sub.3 :
R,
where the amount of R added is 0.001 mol % to 10 mol % of the metal expressed by M, M represents at least one alkaline earth metal, R represents at least one rare earth element, 0.5<a.ltoreq.0.99, 0.001.ltoreq.x.ltoreq.0.35, and 1.ltoreq.n.ltoreq.8 where the composition comprises .alpha.-Al.sub.2 O.sub.3, .gamma.Al.sub.2 O.sub.3 and MO.multidot.(n-x)Al.sub.2 O.sub.3 .multidot.xB.sub.2 O.sub.3 :R where x, n and R have the definition above and the amount of R is 0.001-1 mol % of M.

Dependencies are inferred from the claim text.

Long afterglow phosphor and a process for the preparing thereof

Life of this patent

Long afterglow phosphor and a process for the preparing thereof

Life of this patent

Abstract

Claims10