Multi-configurations in nematic liquid crystal films: A microrubbing approach

We report a technique for the patterned alignment of liq. crystals on polyimide using microrubbing (m-rubbing). Homeotropic polyimide was m-rubbed with a metallic sphere 1 mm in diam. under a specified load of 150 g. We obsd. that m-rubbing induces a high pretilt planar alignment when homeotropic polyimide is used. Liq. crystal cells were constructed from two m-rubbed polyimide substrates, whose rubbing directions are oriented orthogonal to each other. At the intersection points of two m-rubbed lines, a twisted nematic configuration was obsd. In the other sections of the sample, either a splay or homeotropic configuration is realized. A pretilt of 10° was measured in the m-rubbed area. The electro-optical performances of the twisted nematic regions were also investigated