Article

Comprehensive Three-Dimensional Dynamic Modeling of Liquid Crystal Devices Using Finite Element Method

Dept. of Electr. & Comput. Eng., Univ. of Central Florida, Orlando, FL, USA
Journal of Display Technology (Impact Factor: 2.24). 01/2006; 1(2):194 - 206. DOI: 10.1109/JDT.2005.858885
Source: IEEE Xplore

ABSTRACT

In this paper, a comprehensive open-source three-dimensional (3-D) finite-element method (FEM) is proposed to model the dynamic behavior of liquid crystal (LC) directors in complex structures. This dynamic model is based on interactively iterating the vector representation of director profile and potential distribution. The director update formulations are derived in detail from the Galerkin's approach of FEM, including the weak form approach to simplify the highly nonlinear iteration equation. The potential update formulations are derived from the Ritz's approach of FEM. A 2-D in-plane switching (IPS) structure is used as an example to compare our approach with the FEM based commercial software (2dimMOS). The results from both programs show an excellent agreement. Furthermore, our method also agrees well with the finite-difference method (FDM) in studying a 3-D super IPS LC cell with zigzag electrodes.

Download full-text

Full-text

Available from: Shin-Tson Wu, Sep 16, 2015
  • Source
    • "These theories are based on the study of two parameters: the Q tensor, which is related with S parameter (order parameter) [11] or director . The molecular director is more frequently used due to its mathematical simplicity, low computational cost and more accurate results [12]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, a novel algorithm to solve the position of a nematic liquid crystal molecular director inside a device has been proposed. The formulation for minimizing the Gibbs free energy, composed by the free energy deformation (Frank-Oseen equations) minus the electrical energy, has been established using a vectorial representation of the director. The three liquid crystal elastic constants have been considered. The differential equations involved have been solved by applying numerical methods, using an algorithm developed by the authors. It has been compared with other techniques and the main advantages are that the new algorithm is faster and more accurate than other previous methods such as finite difference method (FDT) or a boundary value problem solver of MATLAB (bvp4c). Simulation program is also a powerful tool for analyzing other liquid crystal properties such as refractive index and permittivity as a function of voltage. To validate the simulation results, they have been compared with some measurements of a nematic liquid crystal device manufactured for that purpose. The comparison of birefringences simulated and measured show results that are fairly in agreement. This work also aims to provide a software simulation tool easy to reprogram for more complex devices.
    Preview · Article · Aug 2013 · Optica Pura y Aplicada
  • Source
    • "The proposed TR-LCD structures are optimized using a three-dimensional LC simulator (TECHWIZ developed by Sanayi). The LC distribution is calculated by the finite-element method [14] and the optical properties are calculated based on extended 2 2 Jones matrix methods [15], [16]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Two single-cell-gap transflective display devices with vertically aligned positive dielectric anisotropy liquid crystal driven by horizontal electric fields are proposed. In these displays, patterned reflectors are located at transmittance-inefficient regions to serve as reflective mode. These displays exhibit fast response time, high transmittance, and wide view with optical compensation. Potential applications of these displays for sunlight readable mobile devices are emphasized.
    Full-text · Article · Jun 2010 · Journal of Display Technology
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel liquid crystal (LC) lens with an on-line tunability on focus length and optical axis is proposed in this study. The designed lens has a LC layer sandwiched by two ITO glasses, one of which is patterned with three sector electrodes. With varied sets of pre-designed voltages applied to these three electrodes, the LC lens can not only render focusing effects but also tunability on the optical axis of the lens to an arbitrary axis. A vector-form equation is developed to predict the direction of axis tuning. Simulations are next conducted to predict dynamics of the LCs in the lens and also the focusing and axis-tuning properties of the lens. Important sizes and materials and fabrication process of the lens are determined and optimized based on simulation results. The designed LC lens is fabricated, and then experiments are conducted to demonstrate the performance of the designed LC lens on axis tuning. It shows that the focusing axis of the LC lens can be effectively changed by pre-calculated combinations of three voltages. It is also shown that the average movement of the focal point per applied voltage reaches 4.778 μm/V.
    No preview · Article · Sep 2012 · Microsystem Technologies
Show more