| 摘要 |
Provided is a method for manufacturing an optical film having such a double refraction as can be used as the polarizing plate protecting film or the like for a liquid crystal display device (LCD). Even in case a wide belt support is used for the film production, the optical film manufacturing method can keep a less meandering stable transfer state to eliminate the poor drying of cast film (or web) end portions or the deterioration of a film flatness thereby to achieve a stable high productivity. In the manufacture of the optical film according to a solution-casting film forming method, the belt support has a width of 1.8 m or more, and the thickness (Te) of the two right and left end portions having a width (We) of 2 to 25 % of the whole belt support width (W) from the two side edges is smaller by 5 to 20 % than the thickness (T) of the remaining portion containing the widthwise central portion of the belt support. Alternatively, the modulus (Ee) of longitudinal elasticity of the two right and left end portions of the belt support is smaller by 5 to 20 % than the modulus (E) of longitudinal elasticity of the remaining portions containing the widthwise central portion of the belt support. ® KIPO & WIPO 2009 |
