Abstract

Nematic liquid crystal (NLC) devices are an established electrooptic technology. However, applications are often limited by the slow switching speed. Viscoelastic relaxation restricts cycle rates to 1 kHz under the most favorable surface-mode NLC configuration. The NLC couples to the applied electric field via an induced dipole response; hence the coupling is independent of field polarity. The ferroelectric liquid crystal (FLC) has the advantage of a permanent dipole moment, which couples first order to the electric field, providing a sign dependence on the applied voltage.¹ This gives drive-on and drive-off capability and hence a much faster cycle rate. Submicrosecond switching speed has been demonstrated, which with further materials development could approach 10 ns. The FLC can function as a bistable optical switch with either state stored indefinitely at zero applied voltage. This favors large scale passive X-Y matrix addressing, which has recently been demonstrated.

© 1986 Optical Society of America