UNIFORM MICRODROPLET FORMATION OF POLYMER-DISPERSED LIQUID-CRYSTAL USING UNDERCOATING FILMS

It is found that liquid crystal microdroplets become uniform and their sizes are reduced if the substrates are coated with some undercoating film before forming polymer-dispersed liquid crystal using the photop olymerization-induced phase separation method. In this study, polyviny lalcohol was used for the undercoating film because it has good wettin g property to the liquid-crystal material, resulting in suppression of nonuniform nucleation and growth of the microdroplets. In the polymer -dispersed liquid crystal formed under ultraviolet (UV) irradiation wi th 10 mW/cm(2), the diameter of the liquid-crystal droplets varied in a range up to approximately 6 mu m without using an undercoating film while the variation of the droplet diameters became less than 2 mu m w hen the undercoating film was used. As a result, the threshold charact eristic in the electrooptic property, response time, spatial resolutio n, and film uniformity were improved drastically by using the undercoa ting film. By using the polymer-dispersed liquid crystal formed in thi s new method, a high limiting resolution (as high as 128 1p/mm) was ac hieved. The polymer-dispersed liquid crystal formed in this way is exp ected to be used for projection displays with high resolution and high brightness.