| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase difference film which exhibits reverse wavelength dispersibility and can be made thinner.SOLUTION: A phase difference film is made of a thermoplastic resin containing a polymer having constituent units of a unit represented by a formula (A) and an α,&bgr;-unsaturated monomer unit having a heteroaromatic group, and satisfies expressions (1) through (4). (1) Re(590)>100nm; (2) Rth(590)>0nm; (3) Re(447)/Re(590)<1; (4) d<100 μm. Rthrough Rof the formula (A) independently represents hydrogen or an organic residue having a carbon number of 1-20. In the expression (1) through (4), Re(447) and Re(590) represent in-plane phase retardation of the phase difference film for the measurement wavelength of 447 nm and 590 nm, respectively, and Rth(590) represents thickness retardation of the phase difference film for the measurement wavelength of 590 nm, while d represents a thickness of the phase difference film. |
