IMPROVEMENTS IN FABRICATION CONDITIONS OF LIQUID CRYSTAL-POLYMER COMPOSITE CELLS

For the development of reflective flat displays, polymer liquid crysta l composite is a good potential challenger material. Ln order to reduc e the driving voltage and to enhance the brightness of the backscatter ed off-state, it is necessary to understand and optimise the composite formation. Based on a suitable liquid crystal and polymer couple, we describe a model for the fabrication of polymer dispersed liquid cryst al. The influence of the main parameters on the composite production i s studied. We choose the case of polymerization-induced phase separati on, by means of ultra violet light polymerizing monomer. This study sh ows how the polymerization parameters control the droplet size and the remaining monomer content, both of which play a role in back-scatteri ng and saturation voltage. We bring to light, the strong temperature s ensitivity of PDLC formation and the necessary precautions to reach th e optimum performance of the chosen liquid crystal-polymer couple. As this step is essential to exploit PDLC systems, it could also be syste matically used to compare then under the best conditions.