OPTICAL FILM AND METHOD FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical film, in which foaming due to inclusion of accompanied air is eliminated even when production speed of the film is increased, in which an optical film with excellent flatness is obtained by reducing irregular film thickness and eliminating transfer failure due to droplet scattering of an excess liquid portion of a dripped scale solution liquid, and in which a thin and wide optical film having high productivity and superior quality as well as capability of high-speed film making can be manufactured, in an optical film in use for a protective film, for example, for a polarizing plate in a liquid crystal display device. SOLUTION: In the method for manufacturing the optical film by a solution casting film-making method, outside walls are erected respectively in the outer side of both right and left side-walls and the rear wall of a decompression chamber having a main decompression chamber, with a prescribed space apart from these walls. Thus, a sub decompression chamber opened on the lower side is formed that is situated on the outer side of both right and left sides and the rear part of the decompression chamber, making the pressure reducing force of the sub decompression chamber greater in the range of -30 to -300 Pa than that of the main decompression chamber. COPYRIGHT: (C)2011,JPO&INPIT