| 摘要 |
PROBLEM TO BE SOLVED: To provide a stretched cellulose ester film accompanied neither by cramping troubles along the lengthwise direction thereof in a case of being stretched at a high draw ratio so as to broaden the width thereof nor by the creasing and wrinkling of film edges on an occasion for conveying the film at a high speed and yielding, even after having been width-broadened, miniscule deviations, along in-plane directions, of the retardation Ro in the respective film portions.SOLUTION: In the provided stretched cellulose ester film, the average value of surface roughnesses (Ra) of edges of a film A plane is 1.7 nm to 4.0 nm and is higher than the average value of surface roughnesses (Ra) of the middle portion of the film A plane by at least 0.1 nm and no more than 1.0 nm, and the average value of moduli of elasticity of the middle portion is 3.0 GPa to 8.0 GPa and is higher than the average value of moduli of elasticity of the edges by at least 0.1 GPa and no more than 2.0 GPa. |
