| 摘要 |
<PICT:1036764/C4-C5/1> A luminescent screen, e.g. for X-ray image converters, comprises a transparent support 1 carrying a layer 2 of fluorescent crystal material in an inorganic binder, and a continuous film 3 of silicone resin applied over layer 2 and providing a smooth undersurface for a reflective metal coating 4. During manufacture, an aqueous suspension containing zinc and cadmium sulphide crystals with silver as activator, nickel for reducing image persistence, and borax as binder is deposited by sedimentation on a lime glass support 1. Silicone resin, dissolved in toluene, is then applied over the dry fluorescent layer, and the assembly heated to polymerize the resin and eliminate solvents. Finally, a film of aluminium is deposited by evaporation. The fluorescent material may alternatively comprise calcium tungstate activated with tungsten, or sodium iodide and caesium iodide activated with thallium iodide for g -ray image converters. Also the reflective metal coating may be of Cu, Ag, Cr, Ni, Au or In, and the binder of silica or alkaline-earth silicates. |
