OPTICAL FILM, ITS MANUFACTURING METHOD, POLARIZATION PLATE USING OPTICAL FILM AND LIQUID CRYSTAL DISPLAY DEVICE

PROBLEM TO BE SOLVED: To provide a smooth optical film used as the protective film or phase difference film of the liquid crystal element, that is, the polarization plate of a liquid crystal display device, reduced in foreign matter trouble, containing an additive such as a matting agent or the like in a uniformly distributed state and free from trouble such as a die line or the like, its manufacturing method, the polarization plate and the liquid crystal display device. SOLUTION: The optical film is manufactured by melt extrusion molding. A resin raw material pellet and a powder are melted and kneaded in an extruder to manufacture a mixture pellet, the mixture pellet is melted in the extruder and the molten pellet is cast on a support from a casting die to form a film. Alternatively, the raw material pellet and the powder, both of which are composed of a thermoplastic resin, are melted and kneaded in the extruder and the molten mixture is cast on a metal support as it is from a casting die to form the film. The powder is bonded to the surface of the raw material pellet when the raw material pellet and the powder are charged in the extruder. The raw material pellet and/or the powder is charged for the purpose of the bonding of the raw material pellet and the powder. COPYRIGHT: (C)2008,JPO&INPIT