Process for the preparation of a red emitting phosphor coated with red iron oxide and its application

摘要

Filter phosphors consist of phosphor particles coated with a filter material. A phosphor which shows a red emission when excited by cathode rays may be coated with red iron oxide by producing a thin layer of pyrite on the phosphor particles and thereafter converting the said layer into hematite. Thus, the surface of the phosphor particles is evenly coated with a uniform, dense pigment layer of extreme adherence. The filter phosphors thus obtained are used in cathode ray tubes and especially in color picture tubes.