Switching characteristics of a bistable cholesteric twist cell

Abstract

We recently described the structure of a liquid-crystal twist cell possessing bistable states while a holding field is applied. We now present detailed measurements of operating parameters and switching characteristics. The voltage range for bistable operation and the switching times were determined as functions of temperature and of cell thickness to pitch ratio. We have shown that the holding voltage cell can be matrix addressed using either 2:1 or 3VH matrix addressing, although the cell is best suited for 3VH addressing. Using E-7 liquid-crystal mixture doped with cholesterol nonanoate, a 15 μ cell can be written with a 20-msec pulse of three times the holding voltage or about 5 V.