Patent ID: 7910168

Claim:
A method for forming a film on a substrate, comprising steps of: (1) blending precursor, solvent, de-ionized water and catalyst to form sol solution; (2) standing the sol solution for a period of time to form gel solution; (3) mixing the gel solution with diluent in proportion between 1:0.5 to 1:5 to form coating solution; and (4) coating the coating solution onto the substrate and then drying the coating solution to form a film between 22 micron to 1.5 micron on the substrate; wherein the mixture of the gel solution and the diluent in proportion between 1:0.5 to 1:5 is used to form the film of different thickness between 22 micron to 1.5 micron; and wherein the mixture of the gel solution and the diluent in proportion 1:0.5 is used to form the film of thickness 22 micron; the mixture of the gel solution and the diluent in proportion 1:1 is used to form the film of thickness 17 micron; the mixture of the gel solution and the diluent in proportion 1:2 is used to form the film of thickness 7 micron; the mixture of the gel solution and the diluent in proportion 1:3 is used to form the film of thickness 4 micron; the mixture of the gel solution and the diluent in proportion 1:4 is used to form the film of thickness 2 micron; the mixture of the gel solution and the diluent in proportion 1:5 is used to form the film of thickness 1.5 micron.