| 摘要 |
PROBLEM TO BE SOLVED: To accomplish a λ/4 or λ/2 plate in a wide wavelength region using one sheet of polymer film excellent in durability. SOLUTION: A phase difference plate consisting of one sheet of polymer film wherein a retardation value (Re450) measured at 450 nm wavelength and a retardation value (Re590) measured at 590 nm wavelength are 100-125 nm and 120-160 nm, respectively, and a relational formula Re590-Re450>=2 nm is satisfied and having 4,000-10,000 MPa elastic modulus in a certain direction in the plane or the ratio of the maximum elastic modulus to the minimum elastic modulus in the plane of 1.0-5.0 is used as a λ/4 plate. |
