Homeotropic reverse-mode polymer-liquid crystal device

We have proposed a new type of reverse-mode polymer-liquid crystal device: homeotropic reverse-mode polymer-liquid crystal (HRPLC). This device consists of a liquid crystal with a dielectric constant having negative anisotropy and a pair of glass plates covered with a homeotropic alignment layer. The HRPLC’s operation is the reverse of the usual; i.e., it is clear when no voltage is applied and opaque under applied voltage. We have confirmed that the HRPLC operates well in reverse mode and have studied the dependence of its properties on liquid crystal material, curing process, and cell thickness. Experimental results indicate the HRPLC has a 30:1 contrast ratio over an operating voltage range of 0–11 V. In special fabrication conditions, the transmittance–voltage curve of the HRPLC drops to a minimum at a certain voltage level and begins to increase at that point. We have proposed a model to explain this result.