In this study, a liquid-crystal display (LCD) with the capability of switchable viewing-angle is proposed. The contrast ratio of the LCD mainly depends on the transmittance of the bright state and the dark state. By using the improved structure of the pixel electrodes, the viewing angle of the LCD can be switched between the wide viewing-angle mode and the narrow-viewing angle mode. Based on the proposed three-electrode structure, the liquid-crystal orientation of the LCD is controlled to generate different light-leakage conditions at large viewing angles, thus, resulting in the switch of the viewing angle of the LCD. The proposed structure, which has the slim outline and low-cost of the LCD, is a simple way to control the viewing angle of the LCD. Potential applications for the protection of personal privacy are emphasized.

In this study, a liquid crystal display (LCD) is proposed to have a capability of viewing-angle-switching in all directions. In the proposed LCD, a three-electrode structure is used to control the viewing angle of the LCD. By using a bi-direction slit type electrode, fringe fields with two different directions are generated. The fringe fields cause a light leakage of the dark state in all directions. Experimental results reveal that the proposed LCD has viewing angle within 40o in both vertical and horizontal directions when the area ratio of the vertical and horizontal slit is 1:1. Furthermore, contrast ratio (CR) of the proposed LCD increases as cell gap increases. When the angle between polarizer axis and LC is 0, the proposed LCD has the highest CR in the normal direction. The personal privacy is protected based on the proposed LCD due to the all-direction light leakage in the dark state.