| abstract |
To provide a photosensitive polymer, a phase difference film using the photosensitive polymer, and an optical film using the phase difference film. A solution is a photosensitive polymer having a constitutional unit represented by formula (1): n n n n n n n n n n n n wherein, in formula (1), for example, R 1 is hydrogen or methyl; a is 2 or 3; p is an integer from 1 to 12; X 1 is —O—, —COO— or —OCO—; b is an integer from 0 to 3; A 1 is a divalent group selected from 1,4-phenylene or naphthalene-2,6-diyl, and in the divalent group, at least one of hydrogen may be replaced by fluorine or chlorine; Z 1 is a single bond, —COO—, —CH═CH—COO—, —CH 2 CH 2 —COO—, —CH 2 O— or —CONH—; W 1 and W 2 are hydrogen, fluorine or 1-5C alkyl or alkoxy; Y 1 is —O—; and R 2 is 1-20C alkyl, and at least one of —CH 2 — in the alkyl may be replaced by —O—. |