OPTICAL FILM AND ITS MANUFACTURING METHOD

• Main Author: OGINO KENTARO
• Format: Patent
• Language: English
• Published: 20.05.2004
• Edition: 7
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; METALLURGY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

PROBLEM TO BE SOLVED: To provide a wide optical film having small residual retardation in a wide range along the width direction, small variance of misalignment of the optical axis and to provide its manufacturing method. SOLUTION: The optical film is produced by extrusion molding an amorphous thermoplastic resin and has ≤3 nm residual retardation in ≥80% of the whole area and within ±10° misalignment angle of the optical axis. The amorphous thermoplastic resin film molten and extruded from an extruder into a sheet is pressed and tightly stuck to a cooling roll to be cooled. Or, the temperature of the amorphous thermoplastic resin film just prior to be in contact with the cooling roll is higher by ≥80°C than the glass transition temperature of the resin. The amorphous thermoplastic resin film is pressed and tightly stuck to the cooling roll in 85 to 95% of the whole width of the film at the point where the film is in contact with the cooling roll. Thus, the obtained film has small residual retardation in a wide range in the width direction, small variance of misalignment of the optical axis and can be suitably used for optical purposes and liquid crystal displays. COPYRIGHT: (C)2004,JPO