| 摘要 |
PURPOSE:To provide a harmless orange fluorescent substance of high luminance and long afterglow, suitable for cathode ray tube for use in display, constituted by specific sulfide fluorescent substance. CONSTITUTION:The objective fluorescent substance of composition formula (X is 0<=X<=0.04) with an afterglow time constant tau1/10 at electron beam excitation <=20msec. Said substance can be obtained by mixing calcium carbonate, magnesium sulfate, manganese sulfate and scandium oxide in specified proportions followed by calcination in e.g. a hydrogen sulfide atmosphere. EFFECT:Change in composition ratio X and either or both of concentrations of stain-affording agent Mn and additive Sc enables chromaticity coordinates to be changed over a considerable range, thus giving desired orange color precisely.
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