Application of FLC/AFLC materials to active-matrix devices

The market of TFT-LCDs has been enlarged during the last 10 years. Notebook computers have been the main application. For this application, twisted nematic mode has been used and demands for other modes has been limited. However, larger size of LCDs for monitors or TV are expected to be the next most promising market. Drawbacks of the twisted nematic (TN) mode for this market were narrow viewing angle and slow switching speed. The viewing angle dependence was overcome by using compensation film or by using new LCD modes, for example in-plane switching mode. The slow response is the last drawback to be overcome to realize excellent moving pictures which will be seriously requested in the near future. Several methods have been proposed for fast response of LCDs. However, the applications of ferroelectric liquid crystalline or antiferroelectric liquid crystalline (AFLC) (FLC) materials to TFT-LCDs should be the most promising one. In this article, the authors will review the application of FLC/AFLC materials to TFT-LCDs, such as deformed helix ferroelectric (DHF) mode, twisted FLC mode, monostable FLC mode, APD mode and the application of frustrated phase. Next, the problems to be solved for the application of these materials to TFT devices will be discussed. Finally, the authors will demonstrate the 15″ XGA TFT-LCD using liquid crystalline material showing frustoelectric LC state, which is driven by newly developed driving technologies.