| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical retardation plate with uniform retardation characteristics extending over a wide band. SOLUTION: The optical retardation plate is provided with a first layer composed of a resin with a positive intrinsic birefringence value and a second layer composed of a resin with a negative intrinsic birefringence value, wherein the first layer and the second layer are birefringent, and is constructed by laminating the first layer and the second layer with their slow axes perpendicularly intersecting with each other. The optical retardation plate consists of five layers with three kinds of materials in which a film composed of a norbornene resin (1), an adhesive layer (2), a film composed of a styrene maleic anhydride resin (3), the adhesive layer (4) and the film composed of the norbornene resin (5) are laminated in this order, wherein orientation directions of the oriented film composed of the norbornene resin and the oriented film composed of the styrene maleic anhydride resin preferably coincide with each other, wherein the adhesive layer is formed of a hot-melt resin and wherein the softening point of the hot-melt resin is lower than Tgs (glass transition temperatures) of the norbornene resin and of the styrene maleic anhydride resin. |
