Tristate switching of a liquid-crystal cell among initial transparent, haze-free dark, and high-haze dark states

Abstract

Tristate switching of a liquid-crystal (LC) device among transparent, haze-free dark, and high-haze dark states is presented. In the haze-free dark state, LCs and dye molecules are twisted so that the incident light is absorbed without light scattering. In the high-haze dark state, LCs and dye molecules are randomly oriented by electrohydrodynamic instability so that the incident light is not only absorbed but also simultaneously scattered. Depending on the application, the optical characteristics of the proposed LC device can be tuned by employing an LC material with the appropriate birefringence value. Since the polymer structure is not used, it shows a clear transparent state with little haze. Owing to its simple switching process and excellent optical performance, the proposed LC device is very promising for the development of a multipurpose switchable window, which can be used for energy saving and privacy protection.