Electro-optical characteristics of two domain normally black-electrically controlled birefringence mode

Abstract

A normally black ECB mode with two domains is presented to improve the low contrast ratio of the conventional, normally white, electrically controlled birefringence [ECB] and gray inversion of twist nematic [TN] modes. This system requires a λ/2 plate to compensate for optical phase retardation at the liquid crystal layer, and a good dark state is then obtained under no-field, indicating a high contrast ratio. The two domain structure to improve the gray inversion was obtained using the ion beam alignment technique. The simulated and measured results showed that the proposed mode can improve the gray inversion and contrast ratio considerably, compared to the TN mode and normally white ECB mode.