Electrical Simulation of Liquid Crystals
Introduction
Liquid Crystals (LCs) are state of matter intermediate between that of a crystalline and a liquid. The optical, mechanical, electrical and magnetic properties of LC medium are defined by the orientation order of the constituent anisotropic molecules. Due to the anisotropy of the electrical properties, the orientation of the LC molecules is effectively controlled by electric fields. As a result, LCs exhibit very specific electrooptical phenomena because of their large birefringence. All of these are important to the functional devices based on LCs, for example, flat panel displays that have been commercialized for decades.
The constituents of LCs are elongated or rod-like molecules and disk-like molecules. The average direction of the molecular long axes defines the director n, which gives the direction of the preferred orientation of LC molecules. The LC molecules reorient in externally applied electric fields because of their dielectric anisotropy. The electric energy of a LC depends on the orientation of the director in the applied electric field. Under a given electric field, the LC will be in the equilibrium state, where the total free energy is minimized.
