SWITCHING RESPONSE OF A POLYMER DISPERSED LIQUID-CRYSTAL COMPOSITE

Control over the switching times of polymer dispersed liquid crystal (PDLC) displays is an area of technological importance. We found that the switching times of a PDLC cell can be effectively controlled by using a dual frequency addressable liquid crystal mixture and driving it with appropriate electric fields. The decay and rise times of such a PDLC cell can be reduced from a few thousand milliseconds to a few hundred milliseconds when driven by a low- and a high-frequency field, sequentially. We have also found that the decay and rise times of PDLC cells depend considerably on the frequency of the driving signal and on the initial light-scattering state of the film (which depends on the sample preparation conditions). Indeed, we found that a PDLC cell having an initial highly scattering state exhibits better switching response times than a PDLC cell with an initially transparent optical state. An attempt is made to elucidate the role of the confinement of the LC to the microdroplets on the switching response of a PDLC cell.