Abstract: This invention relates to luminescent materials, especially to such materials of the type comprising cerium activated yttrium aluminium garnets which may be used in cathode-ray tubes for flying spot scanning devices.In more detail the luminescent material of the invention comprises a yttrium-scandium-gallium-aluminium garnet activated by trivalent cerium and having the formula:Y.sub.3-x Ce.sub.xSc.sbsb.y Ga.sub.z Al(.sub.5-(y+z)).sup.O 12in which 0.02.ltoreq.x.ltoreq.0.1, 0.5.ltoreq.y.ltoreq.2 and 1.ltoreq.z.ltoreq.3, provided that (y+z) is less than 5.

Abstract: This invention relates to luminescent materials, frequently known as "Phosphors" and suitable for use in cathode ray tubes where a high brightness display is required, for example, in the cockpit of an aircraft.In particular the luminescent material of the invention comprises a luminescent material comprising an aluminium garnet host material optionally including at least one of the elements scandium and gallium and activated by trivalent terbium and having a composition according to the formula RE.sub.3 Al.sub.(5-(y+z)) Sc.sub.y Ga.sub.z O.sub.12 :Tb, in which RE is one or more of the elements yttrium, gadolinium, lutetium and bismuth and y and z typically have values in the ranges 0.ltoreq.y.ltoreq.2 and 0.ltoreq.z.ltoreq.5.