Patent ID: 8840974

Claim:
An optical film having a hard coat layer on a cellulose ester film, wherein the cellulose ester film comprises a cellulose ester and an ester compound composed of a furanose structure or a pyranose structure, a sum of a number of the furanose structure or the pyranose structure in the ester compound is 1 to 12, a part of the hydroxy groups of the furanose structure or the pyranose structure in the ester compound has been esterified and a part of the hydroxy groups of the furanose structure or the pyranose structure in the compound remains, wherein 0-90% by weight of the ester compound has no hydroxy group and 10-90% by weight of the ester compound has only one hydroxy group; wherein the cellulose ester has an acetyl group substitution degree X which satisfies 2.8≦X≦3.0; wherein the haze value of the optical film is not more than 2.0%; and when the optical film is cut out into a sample size of 90 cm wide and 100 cm long, all of the 5 tubes of 50 W fluorescent lamps which are fixed in a line at a height of 1.5 m, irradiating the film sample in an angle of 45°, are observed to be straight, or only some part of the irradiating 5 fluorescent lamps are observed to be slightly bending.