| 摘要 |
PROBLEM TO BE SOLVED: To provide an absorptive multilayer film ND (neutral density) filter which is constituted by providing an absorptive multilayer film for attenuating transmitted light in a visible light region on a resin film being a substrate, which is excellent in optical characteristics without changing film structure of the absorptive multilayer film and further in which no crack occurs even under high temperature and high humidity environment. SOLUTION: The resin film before film deposition is subjected to plasma treatment or ion beam treatment to thermally contract the resin film by 0.2% or more. Then an oxide dielectric film layer and a metallic absorption film layer are alternatively laminated by a sputtering method or the like on at least one side of the resin film to form the absorptive multilayer film. Even when the obtained absorptive multilayer film ND is left in an environmental testing machine under the temperature of 80°C and humidity of 90% for 24 hours, no crack occurs in the absorptive multilayer film. COPYRIGHT: (C)2008,JPO&INPIT
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