To provide a method for manufacturing a retardation film by which a retardation film, having a prescribed range of NZ coefficient suitable for an image display device, especially, a liquid crystal display device of a VA (vertical alignment) mode is stably obtained, while suppressing breakage of the film during extension.
In the method for imparting retardation to a resin film by extending the thermoplastic resin film in a first direction and then extending the resin film in a second direction substantially vertical to the first direction, extension in the first direction is performed so that the NZ coefficient of the resin film, after extension is 1.2 to 1.5, and the in-plane retardation Re per 100 m thickness is in the range of 30 to 250 nm and extension in the second direction is performed so that the NZ coefficient of the resin film after extension is 2 to 4.
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UKAMURA TADAYOSHI
ASANO HIDEO
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