The solution of the salt of the polymer electrolyte is used as a dispersant in the dispersion solution containing the pigment and used for forming the first layer (30B, 30G, 30R), and the substance which forms a salt along with the polymer electrolyte is mixed into the solution applied on the pigment layer (30B, 30G, 30R) and used for the second layer, and/or the developing solution. The formed layers are patterned and thus a display screen is obtained.