Optical compensation methods for the elimination of off-axis light leakage in an in-plane-switching liquid crystal display

Optical compensation to improve the wide-viewing-angle characteristics in a liquid crystal display (LCD) is essential for high-quality dark images, especially from the bisector direction of the crossed polarizers. This paper reviews optical compensation schemes for the elimination of off-axis light leakage in an in-plane-switching LCD. A uniaxial film with normal dispersion commonly increases the dark-state light leakage, but it can be used in the opposite manner to remove the dark-state light leakage at off-axis viewing angles. Using symmetrical rotation of the polarization state on the Poincare sphere, the dark-state light leakage over the entire viewing cone for white light can be effectively eliminated.