Long-persistence blue phosphors

A phosphor represented by the formula:

• MO . mAl.sub.2 O.sub.3 :Eu.sup.2+,R.sup.3+
• wherein m is a number ranging from about 1.6 to about 2.2, M is Sr or a combination of Sr with Ca, Ba or both, R.sup.3+ is a mixture of Y.sup.3+ with another trivalent metal ion, Eu.sup.2+ is present at a level from about 0.02 mol % to about 10 mol % of M, and R.sup.3+, is present at a level from about 0.02 mol % to about 20 mol % of M.

A phosphor having the formula:

• Sr.sub.k Ba.sub.p Ca.sub.n O . mAl.sub.2 O.sub.3 :2xEu.sup.2+,2yR.sup.3+
• where k=1-n-p-2x-2y and k is greater than 0, and n and p are numbers greater than or equal to 0 and less than 1, x is a number that can range from about 0.0001 to about 0.05 and v is a number that can range from 0.0001 to about 0.10.

A phosphor represented by the formula:

• MO . mAl.sub.2 O.sub.3 :Eu.sup.2+,R.sup.3+
• wherein m is a number ranging from about 1.6 to about 2.2, M is Sr or a combination of Sr with Ca, Ba or both, R.sup.3+ is a trivalent rare earth metal ion, Bi.sup.3+ or mixtures thereof, Eu.sup.2+ is present at a level from about 0.02 mol % to about 10 mol % of M, and R.sup.3+ is present at a level from about 0.02 mol % to about 20 mol % of M in which a portion of the Al.sup.3+ in the host is substituted by a divalent metal ion or in which a portion of the M.sup.2 in the phosphor is substituted by a monovalent metal ion.