Two distinct, stable alignment states have been observed for a nematic liquid crystal confined in a layer with thickness of 12 m and in square wells with sides of length between 20 and 80 m. The director lies in the plane of the layer and line defects occur in two corners of the squares. The positions of the defects determine whether the director orientation is across the diagonal or is parallel to two opposite edges of the square. The device is multistable because both the diagonal and parallel states are stable when rotated by multiples of 90°in plane.

We present a continuum theory model of switching in a bistable nematic liquid crystal device. The bistability of the device investigated relies on the fact that one of the cell surfaces exhibits two stable anchoring states, that is, two surface director orientations are locally stable. Since the other surface exhibits monostable, homeotropic anchoring there are two possible ground state director orientations within the cell, depending on the director orientation at the bistable surface. We first investigate the stability of these base states and find a critical surface anchoring strength below which only one of the states is stable. We also investigate the process of switching between the two stable states through the application of an electric field and the presence of a flexoelectric polarization. At high field strengths the dielectric interaction with the applied field will dominate the flexoelectric effect and may hinder switching. We find, therefore, that a window of possible field strengths exists within which switching occurs.

A layer of insulating liquid of dielectric constant epsilon(Oil) and average thickness (h) over bar coats a flat surface at y = 0 at which a one-dimensional sinusoidal potential V(x, 0) = V(O) cos(pi x/p) is applied. Dielectrophoresis forces create a static undulation (or "wrinkle") distortion h(x) of period p at the liquid/air interface. Analytical expressions have been derived for the electrostatic energy and the interfacial energy associated with the surface undulation when h(x) = (h) over bar - (1/2)A cos(2 pi x/p) yielding a scaling relationship for A as a function of (h) over bar, p, V(O), epsilon(Oil) and the surface tension. The analysis is valid as A/p -> 0, and in this limit convergence with numerical simulation of the system is shown

In this paper, we review a number of uses of conformal mapping techniques for obtaining director profiles of liquid crystals in confined and semi-confined geometries. In particular, we will consider geometries which allow more than one stable state, some of which are of use in bistable displays. These solutions also allow the investigation of the energy of stable states and enable conclusions to be reached as to how such geometries may be optimised for bistable display applications. Such techniques are also able to provide initial configurations for the solution of more complicated situations where numerical methods are used to investigate switching characteristics

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