Improvement of gamma curve distortion in VA LCD by using optical film patterned retarder

In this paper, we improved the γ-curve distortion at off-axis direction in a 4-domain (4-D) patterned vertical alignment (PVA) liquid crystal (LC) cell by applying a pair of the film patterned retarder (FPR) system with the A-film property at the conventional wide-view (WV) PVA LC cell. In order to achieve the excellent γ-curve in the 4-domain LC cell, we optimized the parameter of the pair of the patterned A-film by using the two-dimensional parameter space method, which calculates the polarization difference between the normal direction and the all viewing directions under voltage applied state. As a result, we confirmed that the gamma distortion index (GDI) of the proposed optical structure is reduced to over 80% without any loss of the optical luminance and the contrast ratio in the dark state.