| 摘要 |
A casting dope (27) prepared from CAP, additive and solvent is cast onto a belt (46) and peeled as a wet film (74) that is drawn in the longitudinal direction in a transporting area (80). In a tenter device (47), while the wet film (74) is stretched in the widthwise direction, a relaxation of the wet film (74) in the longitudinal direction is made. If an extent percentage of the stretch is less than 70%, the relation is started. The wet film (74) is fed out as a polymer film (82) from the tenter device (47). On the polymer film (82), the in-plane retardation increases and the thickness retardation decreases. Thus the optical properties become preferable.
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