TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The aromatic diamine I comprises fluorine-contained and sulfone-contained aromatic diamine I and/or fluorine-contained and sulfone-contained aromatic diamine I and diamine II including 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,2'-bis(trifluoromethyl)-4,4'-diamino biphenyl, alpha,alpha'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 4,4'-bis(2-trifluoromethyl-4-aminophenoxy) benzene, 3,3'-bis(2-trifluoromethyl-4-aminophenoxy) benzene, 4,4'-bis(2-methyl-4-aminophenoxy) benzene, 3,3'-bis(2-methyl-4-aminophenoxy) benzene, 4,4'-bis(2-trifluoromethyl-4-aminophenoxy) biphenyl, 4,4'-bis(2-methyl-4-aminophenoxy) biphenyl,2,2'-bis(4-aminophenoxy phenyl) propane, 2,2'-bis(4-aminophenoxy phenyl) hexafluoropropane, 2,2'-bis(2-trifluoromethyl-4-aminophenoxy phenyl)diphenyl sulfone and 2,2'-bis(2-methyl-4-aminophenoxy phenyl) diphenyl sulfone. The fluorine-contained and sulfone contained aromatic diamine comprises 3,3'-bis(4- aminophenoxy)-5,5'-difluoro diphenyl sulfone, 3,3'-bis(3-aminophenoxy)-5,5'-difluoro diphenyl sulfone, 3,3'-bis(4- aminophenoxy)-5,5'-di(trifluoromethyl) diphenyl sulfone, 3,3'-bis(3-aminophenoxy)-5,5'-di(trifluoromethyl)diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(4-aminophenoxy)diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(3- aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetra(trifluoromethyl)-4,4'-bis(4-aminophenoxy) diphenyl sulfone, 3,3'- 5,5'-tetra(trifluoromethyl)-4, 4'-bis(3-aminophenoxy) diphenyl sulfone, 3,3'-bis(2-methyl-4-aminophenoxy)-5,5'- difluoro diphenyl sulfone, 3,3'-bis(3-methyl-4-aminophenoxy)-5,5'-difluorodiphenyl sulfone, 3,3'-bis(2-methyl-4-aminophenoxy)-5,5'-di(trifluoromethyl)diphenylsulfone, 3,3'-bis(3-methyl-5-aminophenoxy)-5,5'-di(trifluoromethyl)diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(2-methyl-4-aminophenoxy)diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(3-methyl-5-aminophenoxy)diphenyl sulfone, 3,3'-5,5'-tetra(trifluoromethyl)-4,4'-bis(2-methyl-5-aminophenoxy)diphenyl sulfone, 3,3'-5,5'-tetra(triluoromethyl)-4,4'-bis(3-methyl-5-aminophenoxy) diphenyl sulfone, 2,2'-difluoro-4,4'-diaminodiphenylsulfone,3,3'-difluoro-5,5'-diaminodiphenyl sulfone, 3,3'-bis(2-fluoro-4-aminophenoxy)diphenyl sulfone, 3,3'-bis(3-fluoro-5-aminophenoxy) diphenyl sulfone, 3,3'-bis(2-fluoro-4-aminophenoxy)-5,5'-difluoro diphenyl sulfone, 3,3'-bis(3-fluoro-5-aminophenoxy)-5,5'-difluoro diphenylsulfone, 3,3'-bis(2-fluoro-4-aminophenoxy)-5,5'-dimethyldiphenyl sulfone, 3,3'-bis(3-fluoro-5-aminophenoxy)-5,5'-dimethyldiphenyl sulfone, 3,3'-bis(2-fluoro-4-aminophenoxy)-5,5'-di(trifluoromethyl)diphenyl sulfone, 3,3'-bis(3-fluoro-5-aminophenoxy)-5,5'-di(trifluoromethyl) diphenyl sulfone, 4,4'-bis(2-fluoro-4-aminophenoxy) diphenyl sulfone,4,4'-bis(3-fluoro-5-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(2-methyl-4- aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetrafluoro-4,4'-bis(3-methyl-5-aminophenoxy) diphenyl sulfone, 3,3'- 5,5'-tetramethyl-4,4'-bis(2-methyl-4-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetramethyl-4,4'-bis(3-methyl-5- aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetra(trifluoromethyl)-4,4'-bis(2-methyl-5-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tetra(triluoromethyl)-4,4'-bis(3-methyl-5-aminophenoxy) diphenyl sulfone, 2,2'-di(trifluoromethyl-4-aminophenoxy)-4,4'-diamino diphenyl sulfone, 2,2'-di(trifluoromethyl-4-aminophenoxy)-5,5 '-diamino diphenyl sulfone, 3,3'-bis(2-triluoromethyl-4-aminophenoxy) diphenyl sulfone, 3,3'-bis(3-triluoromethyl-5-aminophenoxy) diphenyl sulfone, 3,3'-bis(2-trifluoromethyl-4-aminophenoxy)-5,5'-difluoro diphenyl sulfone, 3,3'-bis(3-trifluoromethyl-5-aminophenoxy)-5,5'-difluoro diphenyl sulfone, 3,3'-bis(2-trifluoromethyl-4-aminophenoxy)-5,5'-dimethyl diphenyl sulfone, 3,3'-bis(3-trifluoromethyl-5-aminophenoxy)-5,5'-dimethyl diphenyl sulfone, 3,3'-bis(2-trifluoromethyl-4-aminophenoxy)-5,5'-di(trifluoromethyl)diphenyl sulfone, 3,3'-bis(3-trifluoromethyl-5- aminophenoxy)-5,5'-di(trifluoromethyl) diphenyl sulfone, 4,4'-bis(2-trifluoromethyl-4-aminophenoxy)diphenyl sulfone, 4,4'-bis(3-trifluoromethyl-5-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tertalfluoro-4,4'-bis(2- trifluoromethyl-4-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-tertalfluoro-4,4'-bis(3-trifluoromethyl-5-minophenoxy) diphenyl sulfone, 3,3'-5,5'-tertamethyl-4,4'-bis(2-trifluoromethyl-4-aminophenoxy) diphenyl sulfone, 3,3'- 5,5'-tertalmethyl-4,4'-bis(3-trifluoromethyl-5-aminophenoxy) diphenyl sulfone, 3,3'-5,5'-terta(trifluoromethyl)-4,4'-bis(2-trifluoromethyl-4-aminophenoxy) diphenyl sulfone or 3,3'-5,5'-tertal(trifluoromethyl)-4,4'-bis(3- trifluoromethyl-5-aminophenoxy) diphenyl sulfone. The alicyclic dianhydride comprises cyclobutane-1,2,3,4-tetracarboxylic dianhydride, cyclopentane-1,2,4,5-tetracarboxylic dianhydride, 2,3,5-tricarboxy-2-cyclopentane acetic dianhydride, bicyclo(2.2.1) heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo(2.2.2) heptane-tricarboxylic acetic anhydride, bicyclo(2.2.2)oct-2,3,5,6-tetracarboxylic dianhydride, bicyclo(2.2.2)oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2 3 6 7- naphthalenetetracarboxylic dianhydride or biphenyl-3,3',4, 4'-tetracarboxylic dianhydride. The organic solvent comprises N-methylpyrrolidone, gamma-butyrolactone, hexamethylphosphoramide, dimethyl sulfoxide, N,N-dimethylacetamide or N,N-dimethylformamide. The catalyst comprises triethylamine, pyridine, quinoline or isoquinoline (preferred), tripropylamine, tributylamine, triethanolamine, imidazole, quinoline, or isobutyl quinoline. The dehydrating agent is toluene or dimethylbenzene. The precipitating agent comprises water, methanol, ethanol, propanol, butanol, isopropanol, n-amyl alcohol or isoamyl alcohol. The mole ratio of the aromatic diamine I with the alicyclic dianhydride is 0.9-1.1:1, preferably 0.95-1.05:1. The solid content of the homogeneous solution is 10-50 wt.%, preferably 15-35 wt.%. The mole ratio of the catalyst with the aromatic diamine is 0.01-1:1, preferably 0.05-0.1:1.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation of (I) comprises dissolving aromatic diamine I in an organic solvent under the protection of inert gas, then adding alicyclic dicarboxylicanhydride, and stirring the mixture until alicyclic dicarboxylicanhydride is completely dissolved to obtain a homogeneous solution, then adding the catalyst and a dehydrating agent into homogeneous solution, mixing and reacting the mixture, removing the dehydrating agent, pouring the mixture into a precipitating agent for precipitation. Preferred Method: The process is carried out at a temperature of 140- 180 degrees C and a time of 6-48 hours. The method comprises dissolving (I) in an organic solvent to obtain a resin solution and then coating the obtained resin solution on the substrate, immersing in deionized water after drying to strip, and obtaining the polyimide film. The drying step is carried out at a temperature of 80-200 degrees C and a time of 1-6 hours. Preferred Components: The initial light wavelength of the polyimide film is less than 300 nm. The light transmittance in visible region of the polyimide film is 90%. The thickness of the polyimide film is 25-150 mu m, preferably 50-125 mu m. The resin solution has a solid content of 10-50 wt.%, preferably 15-40 wt.%. The base material is a glass or stainless steel plate.