Methods for Preparing SSFLC Cells and their Electro-Optical Properties

Abstract

The methods of preparing monodomain cells of ferroelectric liquid crystals are reviewed. A sophisticated novel method based on the epitaxial growth of the smectic phase from a spacer edge under a temperature gradient is concluded to work quite well in preparing SSFLC (surface stabilized ferroelectric liquid crystal) cells of high quality at least for the three phase sequences: (1) Iso → Sm A → Sm C*, (2) Iso → N*→ Sm A → Sm C* and (3) Iso—Sm C*. By using these high quality cells of DOBAMBC, three findings are made: (1) The characteristic “zigzag line” defects are the screw and edge dislocations decorated by the singularities of the director field. (2) A new kind of walls is observed and tentatively assigned, which moves not only in the twisted (splayed) states but also in the uniform state. (3) The bump due to the polarization realignment shows two peaks corresponding to the two kinds of wall movements induced by the applied triangular wave; one is due to the transition from the uniform to the twisted state and the other from the twisted to the opposite uniform state.