The effects of elongated nematic bipolar droplet orientation on the performance of polymer-dispersed liquid crystal films

The effects that the elongated nematic bipolar droplet orientation has on the performance of polymer-dispersed liquid crystal (PDLC) films are elucidated in this paper using modeling and simulation. Important performance criteria are low switching field strength in the on-state, good light contrast between the on- and off-states, and fast relaxation time in the off-state. In particular, the model incorporates the Leslie-Ericksen and Frank liquid crystal theories and an external magnetic field. The model is solved in two-dimensions within an ellipse of aspect ratio 1.5. The numerical results indicate that the PDLC film should be designed with the bipolar droplet axis of symmetry normal to the film plane in order to minimize both the required switching field strength and relaxation time. On the other hand, the PDLC film should be designed with the bipolar droplet axis of symmetry oriented within the film plane in order to maximize the light contrast between the on- and off-states. (C) 2001 Elsevier Science B.V. All rights reserved.