An object of the present disclosure is to implement a coloring pattern with a constant illuminance value on an electrode substrate to thereby increase display reliability and lifetime while reducing delamination of the hole transport layer (HTL) in the post-process. That is, when the roughness of the pattern after post-baking treatment is low, it may cause delamination of the hole transport layer (HTL) and a decrease in lifetime due to defective pixels, and thus a certain roughness can be obtained by minimizing the surface flow by leaving the substrate at a high temperature during post-baking treatment according to the present disclosure.