US 2006/0219978 A1 · Method of Making Narrow-Band UVB-Emitting Phosphors

Abstract

A method is provided for making narrow-band, UVB-emitting, (Y,Gd,Ce,Pr)Mg borate phosphors. The method involves the use of a mixed oxide co-precipitate which is combined with MgO and boric acid and fired twice to form the borate phosphor. The mixed oxide co-precipitate is formed by dissolving sources of Y, Gd, Ce, and optionally Pr, in an acid solution. Oxalic acid or ammonia is added to the solution (or vice versa) to form a co-precipitate of oxalates or hydroxides that are further fired to obtain a mixed oxide co-precipitate. The use of the mixed oxide co-precipitate improves homogeneity and yields a phosphor having a higher brightness with very little or no sticking between the fired cakes and the firing crucibles.

Claims16

Dependent claims

A method of making a narrow-band UVB-emitting phosphor having a composition represented by a general formula (Y1-x-y-zGdxCeyPrz)MgB5O10 where x has a value in a range from 0.02 to 0.80, y has a value in a range from 0.01 to 0.97, and z has a value in a range from 0 to 0.05 and x+y+z<1, the method comprising:

(a) dissolving a source of Y, Gd, Ce, and optionally Pr, in an acidic solution;
(b) forming an oxalate or hydroxide co-precipitate containing Y, Gd, Ce, and optionally Pr, from the acidic solution;
(c) firing the oxalate or hydroxide co-precipitate to form an oxide co-precipitate;
(d) combining the oxide co-precipitate with magnesium oxide and boric acid to form a mixture;
and
(e) firing the mixture twice in a slightly reducing atmosphere to form the phosphor.

3 more elements

Dependencies are inferred from the claim text.

Method of Making Narrow-Band UVB-Emitting Phosphors

Life of this patent

Method of Making Narrow-Band UVB-Emitting Phosphors

Life of this patent

Abstract

Claims16