Jan Frank Strömer

Temperature influence on the dynamics of vertically aligned liquid crystal displays

The strong influence of the complex reverse flow phenomenon on the dynamic temperature behavior of vertically aligned liquid crystal displays (VA-LCDs) has been demonstrated. Good agreement was obtained between theoretical and experimental switching profiles over a wide temperature range (25–75°C). This was achieved using the Leslie–Ericksen theory in a one-dimensional model with material viscosity coefficients obtained from an improved estimation procedure. Such accurate numerical simulations can have a large impact on further improvements of VA-LCDs (e.g., the development of temperature-compensating driving schemes).

Ray-tracing simulations and applications of liquid crystal beam control devices

We have developed a general ray-tracing method in the geometrical-optics approach which enables the modeling of in general inhomogeneous liquid crystal configurations. In this manuscript, we discuss two prominent examples in which we calculate the optical properties of two liquid crystal configurations. We first present simulations of a liquid crystal-based electro-optical device that enables a switching effect due to a back reflection phenomenon. In these simulations, we exploit the optical properties of a liquid crystal with a special Freedericksz alignment. Secondly we present preliminary results of the optical properties of a liquid crystal-based optical element that can actively control guiding and extraction of light. A promising application of such a device can be found in for example beam control devices for lighting applications or applications that require local dimming and highlighting.