A method for forming patterned insulating elements on a substrate includes a plurality of exposure steps of exposing a photosensitive paste provided on the substrate through at least one mask having a predetermined pattern; a developing step of developing the exposed photosensitive paste to form a precursor pattern; and a firing step of firing the precursor pattern to form the patterned insulating elements. This method is applied to a method for forming an electron source and a method for forming an image display device including the electron source.