| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical film produced by using an acrylic copolymer having excellent heat resistance and optical characteristics suitable for producing a compensation film for an IPS mode, and to provide a liquid crystal display device.SOLUTION: The acrylic copolymer comprises 50 to 89 parts by weight of an alkyl (meth)acrylate monomer, 10 to 40 parts by weight of a styrene-based monomer including a cyclic pendant structure, and 1 to 30 parts by weight of a tert-butyl (meth)acrylate monomer and/or 0 to 10 parts by weight of a (meth)acrylamide monomer. A resin composition comprising the above copolymer is provided. The optical film uses the above copolymer. An IPS mode liquid crystal display device is provided, which includes the optical film as a compensation film. The acrylic copolymer has a glass transition temperature of 120 to 200°C. The optical film shows an in-plane retardation value of 80 to 150 nm, a retardation value of 100 to 200 nm in a thickness direction, and a ratio (retardation value in the thickness direction)/(in-plane retardation value) of 1.3 to 1.6. |
