Bimesogenic liquid crystals: New materials for high performance photonics devices and displays

We describe wide temperature range new bimesogenic nematic liquid crystals with high flexoelectro-optic coefficients (e/K),of the order of 1.5-2.0 CN-1 m(-1), high switching angles, > 100 degrees and microsecond response times which may be used to give gray scale devices in both the ULH texture, with an optimum optical in plane switch of 45 degrees at fields of 4V mu m(-1) or less, and in the USH or Grandjean texture (with a unique optically isotropic "field off" black state and contrast ratios of > 1000:1), using "in plane" electric fields, with switching times of the order of 20 mu s. The new materials and devices give mu s level to level switching and the real potential for colour filter free frame sequential colour switching. New highly reflective Blue Phase devices, stable over a 50 degrees C temperature range, in which an electric field is used to switch the reflection from red to green, for example, will be described. Full RGB reflections may be obtained with switching times of a few milliseconds. Finally we will briefly mention potential applications including high efficiency RGB liquid crystal laser sources.