Patent ID: 6881453

Claim:
A film which comprises a polymer having such a structure that the main chain thereof consists of a hydrocarbon skeleton and some of the hydrogen atoms of the hydrocarbon skeleton are substituted by at least one alicyclic group selected from the group consisting of an alicyclic hydrocarbon group having a 4 or more membered ring and an alicyclic heterocyclic group, the amount of the alicyclic group being 60 to 90 wt %, and which satisfies the following formula (A): R (450) /R (550)<1 (A) wherein R(450) and R(5 50) are phase differences on the film plane at a wavelength of 450 nm and a wavelength of 550 nm, respectively; wherein the polymer consists of a recurring unit represented by the following formula (1): wherein R 1 , R 2 , R 3 and R 4 are the same or different and each being a hydrogen atom, aliphatic group having 1 to 10 carbon atoms or alicyclic group having a 4 or more membered ring, with the proviso that at least one of R 1 , R 2 , R 3 and R 4 is an alicyclic group having a 4 or more membered ring; and optionally a recurring unit represented by the following formula (2): wherein R 5 , R 6 , R 7 and R 8 are the same or different and each a hydrogen atom, aliphatic group having 1 to 10 carbon atoms or aromatic group having 6 to 12 carbon atoms.