Patent ID: 9720140
Date: 2017-08-01
CPC Classifications: C07C,C07D,C08B,C08K,G02B,H01L,H05B

Claim:
1. An optical film comprising a cellulose derivative having a glucose skeleton containing a substituent, the optical film having an in-plane retardation Ro 550 within a range of 120 to 160 nm measured at a wavelength of 550 nm under an atmosphere of a temperature of 23° C. and a relative humidity of 55%, and a ratio Ro 450 /Ro 550 within a range of 0.65 to 0.99, Ro 450 /Ro 550 being a ratio of an in-plane retardation Ro 450 measured at a wavelength of 450 nm to the in-plane retardation Ro 550 measured at a wavelength of 550 nm, wherein, the substituent of the glucose skeleton in the cellulose derivative satisfies the following requirements (a) and (b), and the optical film contains a compound A satisfying the following condition defined by an Expression (a1), requirement (a): a part of the substituent contained in the glucose skeleton of the cellulose derivative is a substituent having a multiple bond, and an average degree of substitution of the substituent having a multiple bond is within a range of 0.1 to 3.0 per glucose skeleton unit, requirement (b): a maximum absorption wavelength of the substituent having a multiple bond is within a range of 220 to 400 nm, wherein S represents an orientation degree of the compound A in the optical film, and Sw represents an orientation degree of the compound A in the optical film in the presence of water.