| 摘要 |
PROBLEM TO BE SOLVED: To obtain a liquid crystal display device excellent in visibility such as contrast in a wide viewing angle range by obtaining a phase difference plate which has excellent heat resistance and which can highly compensate double refraction of a liquid crystal cell. SOLUTION: The phase difference plate 1 has the following properties. The principal refractive indices nx, ny (nx>ny) in the plane of the plate, the principal refractive index nz, the direction of the aces X, Y, Z which give the respective principal refractive indices, and the thickness d of the plate satisfy the relation of Re<500 nm, wherein Re is defined by (nx-ny)d. The plate has two optical axes symmetric for the Z axis in the Y-Z plate. The optical member consists of the aforementioned phase difference plate 1 and a polarizing plate 2, and the liquid crystal display device has the phase difference plate 1 or the plate 1 with a polarizing plate 2 on at least one surface of a liquid crystal cell. |
