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 photopolymerization‐induced phase separation method. In this study, polyvinylalcohol was used for the undercoating film because it has good wetting 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 with 10 mW/om², the diameter of the liquid‐crystal droplets varied in a range up to approximately 6 μm without using an undercoating film while the variation of the droplet diameters became less than 2 μm when the undercoating film was used. As a result, the threshold characteristic in the electrooptic property, response time, spatial resolution, and film uniformity were improved drastically by using the undercoating film. By using the polymer‐dispersed liquid crystal formed in this new method, a high limiting resolution (as high as 128 1p/mm) was achieved. the polymer‐dispersed liquid crystal formed in this way is expected to be used for projection displays with high resolution and high brightness.