Polymer-Stabilized Orthoconic Antiferroelectric Liquid Crystals

Abstract

Horizontally surface-stabilized orthoconic antiferroelectric liquid crystals (OAFLCs) provide excellent contrast electrooptic switching. However, in very thin cells the bulk relaxation to the anticlinic state tends to be slow because the synclinic state is upheld by the surfaces. In cells thin enough to accomplish a surface-stabilized state of today's short-pitch OAFLC mixtures, the field-induced synclinic (ferroelectric) states often become metastable making the corresponding bright electrooptic state prevail for long times after the electric field is switched off. Fast relaxation is then achieved by specially designed waveforms. By introducing a polymer network formed by in-situ photopolymerization of a small concentration of a commercial reactive monomer dissolved in the OAFLC, we have succeded to drastically reduce the time for relaxation from the synclinic to the anticlinic state after switching off the field down to about 3 milliseconds at room temperature, without the use of any tailored electronic waveforms. The relaxation time of the polymer stabilized OAFLCs (PS-OAFLCs) is thus shorter than in todays nematic liquid crystal displays, which make PS-OAFLCs attractive for use in future high-contrast, blur-free displays.