Dual frequency liquid crystals: a review

Abstract

We review the recent progress in developing high performance dual frequency liquid crystal (DFLC) materials. A new figure of merit is derived for evaluating the DFLC performance. The dielectric relaxation and electro-optical properties of several high performance compounds, which possess a positive dielectric anisotropy at low frequencies and a relaxation frequency in the kilohertz region, are presented. Potential applications of these compounds are discussed. Compounds with a negative dielectric anisotropy were also compared and discussed. Two experimental DFLC mixtures were demonstrated with one intended for room temperature operation and another for elevated temperature operation.

Keywords:

• dual-frequency liquid crystal
• dielectric relaxation
• figure of merit

Acknowledgements

The authors are indebted to Prof. Xiao Liang for providing us with the N-2 negative LC mixture, and to Dr. Sebastian Gauza for useful discussions.