| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an optical retardation plate by which a wide-band optical retardation plate capable of imparting a uniform optical retardation characteristic to incident light in the entire visible light region can be easily and stably produced. SOLUTION: The method for producing a optical retardation plate has a stretching step for obtaining an oriented film by stretching a laminate with at least one layer containing a norbornene resin (NB layer) and at least one layer containing a styrene-maleic anhydride copolymer resin (ST layer). When the lower one of the glass transition temperatures of the norbornene resin and the styrene-maleic anhydride copolymer resin is represented by Tg(L) deg.C, the stretching temperature T deg.C in the stretching step is (Tg(L)-20)<=T<=(Tg(L)+10). The thickness ratio between the NB layer and the ST layer in the oriented film is (3:1) to (1:1).
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