| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical film which prevents irregularity in the end part of a cast ribbon (ribbon-like resin solution) on the occasion of dope casting and enables high-speed manufacture of the optical film excellent in flatness, in regard to the optical film used for a protective film for a polarizing plate of a liquid crystal image display (LCD), or the like. SOLUTION: In the manufacturing method of the optical film, the film thickness of the end parts located respectively within 30 mm of the right and left side edges of a dope film to be cast onto a support from a casting die is regulated so that a relational expression of 0.8×D<SB>2</SB>+25≥D<SB>1</SB>≥0.88×D<SB>2</SB>+10 be established when the maximum film thickness of the end parts (side end parts) located respectively within 30 mm from the right and left side edges of the optical film is made D<SB>1</SB>μm and the maximum film thickness on the inside (film center side) of the side end parts D<SB>2</SB>μm. COPYRIGHT: (C)2005,JPO&NCIPI |
