| abstract |
This invention provides the optical film with high planarity which can be used for retardation films, etc. of a liquid crystal display device, the manufacturing method of the optical film by the melt casting film forming method, etc. The melt containing the cellulose resin is extruded from the casting die 4 onto the rotary support 5 (cooling roll). The pinching rotary body 6 (touch roll) is pressed against the rotary support 5, and the pinching rotary body 6 presses the melt between the rotary supporting bodies 5 to eliminate the die line and eliminate the thickness nonuniformity. do. Therefore, as a pinching rotor, a nip can be formed between a rotating support body. In addition, the planarity of the film can be effectively corrected by setting the linear pressure of the elastic roll and the temperature of the melt just before being pressed by the nip to a predetermined range. n n Cellulose film, optical film, polarizing plate, liquid crystal display device |