RETARDATION PLATE, OPTICAL MEMBER INCLUDING RETARDATION PLATE AND POLARIZING PLATE, AND DISPLAY DEVICE INCLUDING OPTICAL MEMBER

摘要

PROBLEM TO BE SOLVED: To provide a retardation plate made of a monolayer film, which has 'negative dispersion' characteristics in an extraordinary ray refractive index ne or a birefringence Δn, while minimizing reduction in the transmittance.SOLUTION: The retardation plate comprises a polymer obtained by polymerizing a composition comprising a polymerizable liquid crystal composition and a dichroic dye. The polymer is obtained by polymerizing the polymerizable liquid crystal composition into a predetermined liquid crystal alignment state by use of an alignment film; and the alignment film is composed of a resin film that is obtained by molding by use of a mold having a concavo-convex surface where a plurality of grooves extends substantially parallel to each other and that has a concavo-convex pattern having a groove interval of 50 to 1000 nm and a groove height of 10 to 500 nm on a surface thereof. A retardation Δna×da of the above retardation plate and a retardation Δnb×db of a retardation plate comprising a polymer of the above composition excluding the dichroic dye satisfy expression (1): Δna×da(580)/Δna×da(550)-Δnb×db(580)/Δnb×db(550)>0.SELECTED DRAWING: Figure 1