Osram Sylvania Inc.

Eric A Thomason

Chen-Wen Fan

Thomas M Snyder

A UV-emitting phosphor comprising SrBO:Eu phosphor particles that have been treated to yield a surface layer containing from greater than 0 to about 25 atomic percent aluminum. The holdover stability of the treated SrBO:Eu phosphor improves the 100-hour maintenance in a fluorescent tanning lamp to the extent that the treated phosphor may be subject to a holdover period of more than 25 days without a significant change in its 100-hour maintenance.

UV-emitting strontium borate phosphor with improved holdover stability

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.

Method of making narrow-band UVB-emitting phosphors

The present invention is a single-component, UV-emitting phosphor having a composition represented by the general formula (YLaGdCe)POwhere x has a value in a range from 0.001 to 0.98, y has a value in a range from 0 and 0.1, z has a value in a range from 0.01 and 0.2, and x+y+z&#x3c;1. The phosphor when stimulated by 254 nm radiation emits in both the UVA and UVB regions. The relative balance of the UVA and UVB emissions may be varied by adjusting the relative amounts of Y and La. Brightness can be increased by adding Gd to the composition.

Single-component, UV-emitting phosphor

A narrow-band UVB emitting phosphor is described wherein the phosphor has a preferred composition represented by the general formula (YGdCePr)MgBOwhere 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 greater than 0 to 0.05 and x+y+z&#x3c;1. The phosphor has a narrow emission centered at about 312 nm when excited by radiation from a low-pressure mercury discharge.

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Towanda, PA, United States of America

Eric A Thomason