Operation Principle of Polymer-Dispersed Liquid Crystal (PDLC)
{"Image DocumentName": "Operation Principle of Polymer-Dispersed Liquid Crystal (PDLC)", "Image ImageDescription": "When a sufficient voltage is applied, the PDLC becomes transparent and allows light to pass, while the PDLC is opaque and scatters light without an applied voltage. The PDLC is suitable for an electrooptic material of a light modulation device used in high-brightness projectors, because it exhibits high optical transparency without a polarizer. Nematic phase. See also: Biaxial nematic and Twisted nematic field effect. Alignment in a nematic phase. Phase transition between a nematic (left) and smectic A (right) phases observed between crossed polarizers. The black color corresponds to isotropic medium. One of the most common LC phases is the nematic. The word nematic comes from the Greek \u03bd\u03ae\u03bc\u03b1 (nema), which means thread . This term originates from the thread-like topological defects observed in nematics, which are formally called disclinations . Nematics also exhibit so-called hedgehog topological defects. In a nematic phase, the calamitic or rod-shaped organic molecules have no positional order, but they self-align to have long-range directional order with their long axes roughly parallel.[18] Thus, the molecules are free to flow and their center of mass positions are randomly distributed as in a liquid, but still maintain their long-range directional order. Most nematics are uniaxial: they have one axis that is longer and preferred, with the other two being equivalent (can be approximated as cylinders or rods). However, some liquid crystals are biaxial nematics, meaning that in addition to orienting their long axis, they also orient along a secondary axis.[19] Nematics have fluidity similar to that of ordinary (isotropic) liquids but they can be easily aligned by an external magnetic or electric field. Aligned nematics have the optical properties of uniaxial crystals and this makes them extremely useful in liquid crystal displays (LCD).[8]", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}