Electroluminescent phosphor and its production method

An electroluminescent phosphor production method comprising:

• a primary firing process for firing at a temperature in the range of 1150 to 1350° C. a mixture produced by adding to zinc sulfide (ZnS):
• at least one kind of compounds selected from among copper compounds and manganese compounds as a material of an activator,
• at least one kind of compounds selected from among halides and aluminum compounds as a material of a co-activator,
• at least one kind of compounds selected from among alkaline earth metal oxides and compounds that change into alkaline earth metal oxides when fired, and
• a halide or halides serving as a crystal growing agent;
• an intermediate manufacturing process for producing an intermediate by washing, filtrating, and drying a fired substance resulting from the primary firing process;
• a secondary firing process for crystal transformation of a part of the intermediate produced from the intermediate manufacturing process;
• and
• an etching process for etching the intermediate fired by the secondary firing process.