Electro-optical property of polymerized liquid crystal devices using linearly polarized UV irradiation

Display characteristics have a fairly strong dependence on the configuration of the liquid crystal (LC) molecules and interactions between the LC molecules and the alignment layer surface. To obtain LC devices with a fast response, the usage of reactive mesogens (RMs) have been studied. RMs polymerize in the vicinity of the alignment layer. We assessed the effectiveness of linearly polarized UV light for polymer formation. Three kinds of UV light, namely (i)non-polarized (ii)parallel to, and (iii)perpendicular to the rubbing direction, were used to irradiate LC cells with RM concentrations of 5wt% and 10wt%. For both RM concentrations, LC devices using LPUV parallel to the rubbing direction yielded the shortest decay times. SEM observation revealed that the fibrils polymerized linearly in the same direction on using LPUV parallel to the rubbing direction. The decay time was presumably shortened by the strong anchoring force and high alignment ability of the linear fibrils.