Retardation plate and fabrication method thereof, and plate for circularly polarizing light, 1/2 wave plate and reflection-type liquid crystal display device utilizing the retardation plate

摘要

The present invention provides a broad band retardation plate that can be fabricated by a simple process and uniformly retards light incident of the entire visible light region. The retardation plate contains materials including positive or negative intrinsic double refraction values. When retardation values in wavelengths of 450 nm, 550 nm, and 650 nm are defined as Re(450), Re(550) and Re(650), respectively, the retardation plate satisfies the relational expression of Re(450)<Re(550)<Re(650). The retardation plate has a first layer comprising a positive material and a second layer comprising a negative material. The first layer and second layers have double refraction, and are laminated such that lag axes of the both layers are orthogonally crossed. It is preferable that the positive material is a norbornene based polymer and the like.