Light shutters and electro-optical storage devices from antiferroelectric liquid crystals of bent-shape molecules

摘要

Novel scattering-type displays using antiferroelectric smectic phases of liquid crystals of bent-shape molecules are reviewed and discussed. There can be two distinct states ("racemic" and "chiral") that work in opposite ways. The racemic structure is scattering in the OFF state and is optically clear under sufficiently large (E～4-6V/μm) electric fields. The chiral structure is transparent at zero fields and scattering in the field ON state. These two structures may be reversibly interchanged implying their use in devices that consume energy only during switching from one stable state to the other. After summarizing the previous results on the film thickness, driving voltage and temperature dependences of the light shutters, new results will be presented on a banana smectic material, which has an optically isotropic transparent antiferroelectric OFF state. We show that the optically isotropic and transparent OFF state can be reversibly switched to birefringent and scattering ferroelectric states in less than hundred microseconds.