We developed a phenomenological theory to describe the aligning field of polymer networks in polymer stabilized liquid crystals where sub-micron size polymer networks are phase separated from the liquid crystal in dispersion. The polymer networks are anisotropic and anchor the liquid crystals in their longitudinal direction. They inhibit the liquid crystals reorientation when external stimuli, such as electric field and temperature, are applied and reduce the relaxation time from distorted states. We model the effects produced by the polymer networks as an effective aligning field. We calculate the effective field as a function of the polymer network volume fraction and the lateral size of the network. The theory is compared with experimental results and good agreements were obtained. It is very useful in predicting how much polymer networks change the driving voltage and response time of liquid crystal devices.

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We developed a waveguide liquid crystal display from a liquid crystal (LC)/polymer composite. It does not need polarizers or color filters. It is illuminated by color LEDs installed on its edge. The light produced by the edge LEDs is coupled into the display and then waveguided through the display. When the LC is in the transparent state, the incident light is waveguided through and no light comes out of the viewing side of the display. When the LC is in the scattering state, the incident light is scattered and comes out of the display. It can be used either for transparent display or for direct view display. The composite has a submillisecond response time, and a field sequential scheme can be used to display full color images. Because the display does not need polarizers or color filters, its energy efficiency is much higher than current liquid crystal displays.

In this article, we report on a novel technique for fabricating an electrically switchable Fresnel lens made from liquid-crystal–polymer composite. The Fresnel pattern is formed by means of interference between two planar and spherical wavefronts reflected from a single plano-convex lens. The simplicity of the procedure and capability to fabricate different focal lengths with the same arrangement are the unique advantages of this technique.