OPTICAL FILM

摘要

PURPOSE: An optical film is provided to control the retardation without adding a retardation controlling agent by cutting off the optical anisotropy of a cellulosic resin by adjusting the substitution degree and the kind of a substituent. CONSTITUTION: An optical film includes a cellulose ester resin containing cellulose with a hydroxyl group in which partial hydrogen is substituted to two acyl groups selected from an acetyl group and a propionyl group, or the acetyl group and a butyryl group. Non-substituted hydrogen in the hydroxyl group is substituted into a substituent denoted by chemical formula 1 or 2. The substituent denoted by the chemical formula 1 or 2 has the substitution degree of 0.01-1.0.