2-DIMENSIONAL FINITE-ELEMENT MODELING OF NEMATIC LIQUID-CRYSTAL DEVICES FOR OPTICAL COMMUNICATIONS AND DISPLAYS

A two-dimensional finite-element code is presented for the steady-stat e analysis of liquid crystal structures in nonuniform electric fields. It is based on a free-energy formulation which includes all three ela stic constants and can deal with pure nematic, twisted nematic, and ch olesteric liquid crystal materials. The enhanced capabilities of our c ode allow the design of composite structures made of both dielectric a nd liquid crystal materials and with arbitrary configuration of electr odes. Unwanted effects, such as the formation of disclination lines in the director orientation, can be accurately predicted. The method has been applied for analyzing pure nematic liquid crystal microlenses wi th variable focal length and twisted nematic liquid crystal cells for display applications. Numerical results show that a careful choice of the device structures can avoid the formation of defects and improve t heir performance.