Optical compensation layer, optical compensation film, and processes for producing these

Abstract

Optical compensation layers are provided which have an optically compensating function imparted thereto upon coating fluid application or upon coating fluid application and subsequent uniaxial stretching and which have a small wavelength dependence of retardation. The invention provides: an optical compensation layer wherein the compensation layer is a coating layer comprising a maleimide resin and wherein when two arbitrary axes perpendicular to each other in the plane of the coating layer are referred to as x-axis and y-axis, respectively, and the out-of-plane direction is referred to as z-axis, then the coating layer satisfies the three-dimensional refractive-index relationship nx≈ny>nz, wherein nx is the refractive index in the x-axis direction, ny is the refractive index in the y-axis direction, and nz is the refractive index in the z-axis direction; an optical compensation film which comprises a coating layer (A) comprising a maleimide resin and a stretched-film layer (B); and an optical compensation layer, which is an optical compensation layer obtained by uniaxially stretching a coating layer comprising a maleimide resin, wherein when the direction of stretching axis in the coating layer is referred to as x-axis, the direction perpendicular to the stretching direction is referred to as y-axis, and the out-of-plane direction is referred to as z-axis, then the optical compensation layer satisfies the three-dimensional refractive-index relationship nx4>ny4>nz4, wherein nx4 is the refractive index in the x-axis direction, ny4 is the refractive index in the y-axis direction, and nz4 is the refractive index in the z-axis direction. (wherein Rrepresents a linear alkyl group, a branched alkyl group, or a cycloalkyl group, having 1-18 carbon atoms, a halogen group, an ether group, an ester group, or an amide group).