STRETCHED CELLULOSE ESTER FILM, AND POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a stretched cellulose ester film with improved humidity stability of optical performance, and to provide a polarizing plate and a liquid crystal display apparatus using the film.

SOLUTION: The cellulose ester film is produced by forming a film by using a cellulose ester containing a polyester polyol prepared from a glycol (a) having 2 to 3.5 average carbon number and a dibasic acid (anhydride) (b) having 4 to 5.5 average carbon number, and then stretching the film. The retardation Ro in the film plane defined by formula (I):Ro=(nx-ny)×d ranges from 30 to 200 nm, and the retardation Rt in the film thickness direction defined by formula (II):Rt=ä(nx+ny)/2-nz}×d ranges from 70 to 400 nm.

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