Reduced off-axis gamma shift of liquid crystal display by intercepting transmittance method

Abstract

Generally, the brightness and color of one image on a large-area flat panel display are different when people watch a display image under different viewing angles. The gamma shift is used to evaluate the difference of electro-optical performances under different viewing angles, namely the gray-scale display distortion. In order to reduce the gamma shift under the oblique viewing angle, the intercepting transmittance method is proposed and illustrated based on the single-domain in-plane switching blue-phase liquid crystal display (IPS-BPLCD). The results show that the off-axis image distortion index (the quantitative evaluation index of gamma shift) can be reduced by ~72% if the transmittance ratio reduces from 100% to 80% for the IPS-BPLCD with a straight electrode structure. Moreover, the zigzag electrode structure is used as the reference to illustrate the merits of the proposed method. As a result, the operating voltage of the IPS-BPLCD can be reduced by >20%, and the off-axis image distortion index is reduced by ~47% compared with the zigzag electrode structure. Besides this, the effects of the proposed method on contrast ratio, operating voltage and color difference of IPS-BPLCD are investigated as well. In fact, the proposed method is also useful for other LCD modes and electro-optical devices to achieve wide and uniform viewing angles.