Maciej Wnek

Comparative studies of the multiplexability of SSFLC devices with respect to alignment characteristics

Abstract Several series of Surface-Stabilized Ferroelectric Liquid Crystal (SSFLC) cells were prepared using different aligning techniques (obliquely evaporated SiOx, buffed polyimides and nylon). The surface structure of aligning layers were studied by Atomic Force Microscopy (AFM). The samples were filled with various commercial FLC materials from Merck, BDH and Chisso. Our investigations were focused on the correlation between the aligning layer and the electro-optic characteristics of the SSFLC samples. The strength of the elastic torque is related to the surface conditions and evaluated using a specially designed test waveform. The switching properties and image sticking phenomenon have been studied under real addressing conditions.

Anchoring conditions for different aligning materials from dielectric behavior of SSFLC cells

The dielectric response of thin surface stabilized ferroelectric liquid crystal cells with different aligning materials and filled with the same FLC mixture are studied and compared in the low frequency dielectric regime. For the measurements we adopted an improved cell structure with metallized pixel connections. In the FLC material in question, Merck SCE 13, only one absorption appears corresponding to a collective mode.It is ascribed to the Goldstone mode in the bulk FLC. From our measurements we calculate the surface anchoring energy density for the different aligning materials and discuss changes induced in dielectric spectra by a DC bias field.

Performance of a passive matrix ferroelectric liquid crystal display with analog grey levels

Ferroelectric liquid crystals (FLC) are suitable materials for low power and low cost flat panel displays. In this paper fabrication and performance of a surface stabilised ferroelectric liquid crystal display with analog grey scale levels are reported. Grey shades are produced by width control of FLC microdomains by means of a gradient of electric field distributed over the pixel, between adjacent columns. Such gradient, depending on the data voltages, is achieved by using high resistance film deposited on the column substrate. The authors discuss the choice of teflon layers, easily deposited by friction, to align the smectic liquid crystal molecule layers. The overall fabrication process is low cost and produces shock resistant displays. The choice of the addressing mode is reported. Optical response of the display shows very low hysteresis and sticking effect under driving conditions.

On the Improvement of the Optical Properties of the Dichroic Dyes and Liquid Crystal Mixtures. A Model Studies

Abstract Guest-host type mixtures of a liquid crystal and dichroic dyes are theoretically analyzed by means of the Flory–Ronca lattice theory. The results are compared with experimental data. The influence of the temperature, molecular soft- and steric interactions, dyes (guest) ratio and presence of different dopants on the optical properties of the mixture is also analyzed.

Simulation of the molecular dynamics of rod-like molecules in semidiluted solution : a dielectric relaxation study

Abstract The dielectric relaxation of a model solution of polydisperse rods is studied numerically, using a modified Doi-Edwards model. A new model of the dielectric relaxation in the biphasic range of concentration is proposed.