Director orientation in chevron surface-stabilized ferroelectric liquid crystal cells. Verification of orientational binding at the chevron interface using visible polarized light transmission spectroscopy

Abstract

We present results of theoretical modelling and experimental study of director distributions and the associated optical properties of chevron surface stabilized ferroelectric liquid crystal (SSFLC) cells. Chevron cells are modelled as being two stacked FLC slabs, described by distinct orientation distributions of the director [ncirc]-polarization P([ncirc] – P) couple. In each slab the [ncirc] – P distribution is governed by bulk Frank elastic and electric field-induced torques and by surface torques at the FLC-solid interface and at the chevron interface, where the two distributions are coupled. The optical properties of such structures are calculated numerically and the results tested using polarized light microscope-based spectrophotometric measurements of the wavelength dependent transmission of chevron SSFLC cells with varying sample orientation and applied field. Measured transmission spectra agree quantitatively with the model and provide evidence for the constraint of the ň – P field at the chevron interface, particularly in the case when the chevron interface is displaced from the cell midplane.