Alignment instability caused by anchoring of the in-plane directors to therubbing direction in the V-shaped switching

In order to investigate the molecular alignment in the smectic liquid cryst als showing the V-shaped switching behavior, two types of the liquid crysta l cells, a sandwiched cell and an open cell, were prepared. Homogeneous ali gnment with the smectic layer normal formed at similar to 12 degrees with r espect to the rubbing direction n is obtained in the Sm-A phase in both cel ls. However, in the open cell, the director n is rotated towards r when the Sm-A sample is cooled into the tilted Sm-X* phase. In addition, its maximu m rotation angle is similar to 12 degrees. In this configuration, the molec ules lie along r. Meanwhile, the sandwiched cell with the one-side rubbing treatment exhibits the averaged optical axis almost parallel to the layer n ormal in the Sm-X* phase. In this paper, a simple small-twisted state in th e thin sandwiched cell is suggested to account for the experimental results .