Method for producing optical film

A method for producing a multilayered optical thin-film composed of a plurality of thin-films, the method comprising:

• forming the multilayered optical thin-film on a film substrate by sputtering in a roll-to-roll sputtering deposition apparatus while the film substrate is continuously conveyed in the roll-to-roll sputtering deposition apparatus, the sputtering deposition apparatus including a plurality of sputtering chambers along a substrate conveyance direction and an optical measuring unit configured to measure an optical property,
• the sputtering including
• preliminary deposition in which deposition conditions of thin-films are adjusted while forming the thin-films on the film substrate in the roll-to-roll sputtering deposition apparatus;
• and
• main deposition performed after the preliminary deposition,
• wherein the main deposition is performed to form the multilayered optical thin-film including all the plurality of thin-films using the deposition conditions adjusted during the preliminary deposition,
• wherein the preliminary deposition includes a plurality of adjustment steps, each adjustment step adjusting deposition conditions of corresponding one or more, but not all, of the thin-films included in the multilayered optical thin-film, while continuously conveying the film substrate along the substrate conveyance direction and forming at least one of the thin-films, including the corresponding one or more of the thin-films, on the film substrate,
• wherein, in at least one of the plurality of adjustment steps, a stack of thin-films made of two or more different materials is deposited on the film substrate by simultaneously energizing two or more of the sputtering chambers, and an optical property of a stacked body in which a plurality of thin-films are formed on the film substrate is obtained by the optical measuring unit,
• wherein, in the at least one of the plurality of adjustment steps, thicknesses of the plurality of thin-films are calculated from the optical property obtained by the optical measuring unit, and the deposition conditions for the respective thin-films are adjusted until the optical property obtained by the optical measuring unit or the thicknesses of the respective thin-films calculated from the optical property falls within a predetermined range, and
• wherein at least one of the plurality of thin-films which constitute the multilayered optical thin-film is a stack of a plurality of sub-thin-films wherein each of the plurality of sub-thin films is made of an identical material, and wherein each of the plurality of sub-thin film is deposited in a separate sputtering chamber of the plurality of sputtering chambers,
• and
• deposition conditions are adjusted separately for each sub-thin film of the plurality of sub-thin-films in said separate sputtering chamber of the plurality of sputtering chambers.