Patent ID: 7252790

Claim:
A method for producing zinc sulfide electroluminophores which have an average grain size of from 2 to 20 microns comprising: (a) preparing a fine-grain zinc sulfide by precipitating zinc sulfide from solutions of zinc salts and H 2 S; (b) mixing the obtained fine-grain zinc sulfide with activator and co-activator compounds to form luminophores; (c) firing the obtained mixtures at a temperature range of from 800 to 1000° C. in the presence of fluxing agents selected from the group consisting of fluorides, bromides, iodides, and mixtures thereof, to obtain powdery electroluminophores; (d) changing the morphology of the zinc sulfide by treating the powdery electroluminophores with an acid selected from the group consisting of organic acids, inorganic acids, and mixtures thereof in an acid bath while stirring.