Preparation of bistable nematic (Bi-Nem) LC cell with optical alignment methods

摘要

To realize the bistable nematic (Bi-Nem) liquid crystal (LC) display, it is required for one of the substrates, in addition to that the polar anchoring is as weak as possible, that the azimuthal anchoring is strong enough to ensure the bistable operation. For this requirement, we attempted to apply the optical-alignment method. Prior to fabricating the Bi-Nem LC cell, the relationship between the azimuthal anchoring energy and the irradiation energy of polarized UV light for some kinds of polyimide as alignment was measured. As the result, we could obtain the maximum azimuthal anchoring energy of 7.42×10{sup}(-5) J/m{sup}2 at the irradiation energy of 1.95 J/cm{sup}2 using PI-A (synthesized by Nissan Chemical Industry Co.). Using the substrate treated by the optical-alignment method under such condition, we made the Bi-Nem LC cells and confirmed experimentally the bistable operation in those cells.