Achromatic optical compensation using dispersion of uniaxial films for elimination of off-axis light leakage in a liquid crystal cell

We propose an achromatic optical-compensation method using uniaxial films to eliminate the off-axis light leakage at the dark state in a homogeneously aligned liquid crystal cell. Three uniaxial films with different dispersion characteristics are used so that they can compensate each other to achieve achromatic effective phase retardation at off-axis. The retardation values are optimized with the aid of the Poincaré sphere and through numerical research. A contrast ratio of higher than 2000∶1 is predicted over the entire ±60° viewing cone for a homogeneously aligned LC cell with zero pretilt angle.