Biaxial retardation film and fabrication method thereof

A biaxial retardation film, comprising:

• a substrate, wherein the substrate comprises an alignment film thereon or an alignment-treated surface;
• and
• an optically anisotropic coating on the substrate, wherein the optically anisotropic coating comprises a top layer and a bottom layer, wherein the bottom layer and a pillar array of the top layer are orientation structures aligned perpendicular to one another, wherein three-dimensional refractive indices of the optically anisotropic coating satisfy a relationship nx>nz>ny.

A fabrication method for a biaxial retardation film, comprising:

• providing a substrate, wherein the substrate comprises an alignment film thereon or an alignment-treated surface;
• forming an optically anisotropic coating on the substrate, and
• imprinting on the optically anisotropic coating so that the optically anisotropic coating is formed with a structure comprising a top layer and a bottom layer, wherein the bottom layer is a parallel aligned liquid crystal layer along an alignment direction of the substrate, and the top layer is a vertically aligned hexagonal pillar array liquid crystal layer, wherein three-dimensional refractive indices of the optically anisotropic coating satisfy a relationship nx>nz>ny.