Patent Number: 
Section: abstract

A phosphor powder for producing a high resolution phosphor screen and a phosphor screen are provided. The phosphor screen comprises a substrate, an infrared-absorbing layer, and a phosphor layer coated on the infrared-absorbing layer, wherein the phosphor layer comprises a phosphor powder in which a substantial amount of particles in the powder have a particle size as measured in the longest dimension of greater than 0 and less than about 5 microns. The phosphor screen may also comprise a black, infrared-absorbing substrate with the phosphor layer coated on the substrate. The phosphor powder is formed by preparing a phosphor composition, sintering the composition to form ingots, grinding the ingots to form a powder wherein a substantial amount of particles in the powder have a particle size of greater than 0 and less than about 5 microns, reactivating the powder in an inert atmosphere to a temperature of from about 500xc2x0 C. to about 550xc2x0 C., preparing a suspension of the powder and a nonreactive organic solvent, mixing the suspension to separate particles of the powder which partially fuse during reactivation and to break up large agglomerates of the powder in the suspension, decanting the suspension to at least partially separate the nonreactive inorganic solvent and the powder, and drying the powder to form the phosphor powder.