| 摘要 |
PURPOSE:To constitute a titled element so that its surface accuracy and refracted index are not varied even if the environmental condition is varied, by providing a hydrophobic thin film on the surfaces of an optical element by a plasma polymerizing method. CONSTITUTION:On the surface of a base board of an optical element consisting of a resin composite whose coefficient of water absorption by ASTMD-570 is >=0.15%, for instance, a lens, a prism, a reflector, an optical fiber, etc., a hydrophobic thin film is formed by a plasma polymerizing method. For instance, a lens (thickness of the center part is 3mm.) obtained by inject-molding polymethyl methacrylate resin is dried at 50 deg.C for three days, and thereafter, a plasma polymerized film of octafluorocyclobutane is formed under the conditions of 70 deg.C base board temperature, 13.56MHz discharge frequency, 10W high frequency power, 0.1Torr pressure, and such an element is made to absorb water under the conditions of ASTMD-570, 23 deg.C, 100% RH and 24hr, and as a result, its coefficient of water absorption is 0.08% and remarkably below 0.28% of an untreated lens. |
