| 摘要 |
PROBLEM TO BE SOLVED: To provide a cellulose ester film which has optical anisotropy (high retardation value), in which occurrence of color irregularity of a stripe-shape and light leak are not observed, which can be used as an optical compensation sheet of a liquid crystal display device and a protective film for a polarizing plate and is profitable to attain miniaturization, weight reduction and cost reduction of the liquid crystal display device and to provide its manufacturing method. SOLUTION: In the cellulose ester film, a retardation value in a in-plane direction (R<SB>0</SB>) is 20 to 70 nm, a retardation value in a thickness direction (R<SB>t</SB>) is 70 to 400 nm, a gradient of the retardation value in the in-plane direction (R<SB>0</SB>) is≤5 nm/cm, a gradient of the retardation value in the thickness direction (R<SB>t</SB>) is≤10 nm/cm. In the manufacturing method of the cellulose ester film by a solution-casting film-forming method, after exfoliated from a support, a web is stretched substantially in a width direction while drying under conditions where a residual solvent exists till a value of (temperature(°C) at the time of stretching)×(stretching percentage(%)) reaches≥1800. COPYRIGHT: (C)2005,JPO&NCIPI |
