The discovery of ferroelectricity in smectic C liquid crystals, in 1975, has introduced a new electrooptic effect, driven by linear coupling between the permanent electric polarization of chiral smectic C molecules and the addressing electric field. Ferroelectric liquid crystals allow a reduction of at least 3 orders of magnitude of the switching time with respect to conventional twisted nematics, and yield permanent stable states used for memory effects (surface stabilization for small thickness cells and AC stabilization for small and medium thickness cells). All this has open the way to new and faster devices ranging from highly multiplexed displays to optical shutters. The authors describe the present trends in material synthesis, molecular anchoring and device fabrication. New mixtures have been prepared at Thomson-CSF and other laboratories which yield low viscosity materials by using high polarity chiral molecules as dopants. Response times of less than 40 μs have already been obtained and lower ones are forseable. Small pitch (less than 50 μm) optical shutters will be described and applications such like light modulators and line printers will be discussed.

Date Published: 31 January 1989
PDF: 11 pages
Proc. SPIE 1018, Electro-Optic and Magneto-Optic Materials, (31 January 1989); doi: 10.1117/12.949997

Published in SPIE Proceedings Vol. 1018:
Electro-Optic and Magneto-Optic Materials
Jean-Pierre Huignard, Editor(s)