Patent ID: 8758655

Claim:
An optical film comprising: a first acrylic resin including one or more copolymers selected from the group consisting of a copolymer of an acrylic monomer, an aromatic vinyl monomer and an acid anhydride represented by Formula 2; and a copolymer of an acrylic monomer, an aromatic vinyl monomer, an acrylonitrile monomer and an acid anhydride represented by Formula 2; and 20 to 65 parts by weight of a graft copolymer comprising a conjugated diene rubber based on 100 parts by weight of the first acrylic resin, wherein the graft copolymer is a graft copolymer of a conjugated diene rubber and a second acrylic resin for the graft copolymer, wherein the graft copolymer has a core-shell structure in which the conjugated diene rubber constitutes a core and the second acrylic resin for the graft copolymer constitutes a shell, wherein a weight ratio of the conjugated diene rubber and the second acrylic resin for the graft copolymer is in the range of 10 to 50:90 to 50, wherein the optical film has an in-plane retardation value and a thickness retardation value of 0 to 10 nm before stretching, and wherein the optical film has an in-plane retardation value and a thickness retardation value of 80 to 200 nm after stretching, wherein R 7 and R 8 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.