Liquid Crystals
This chapter outlines the basic physics, chemical nature and properties of liquid crystals. These materials are important in the electronics industry as the electro-optic component of flat-panel liquid-crystal displays, which increasingly dominate the inf
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Liquid Crystal 38. Liquid Crystals
38.1 Introduction to Liquid Crystals .............. 38.1.1 Calamitic Liquid Crystals ............. 38.1.2 Chiral Liquid Crystals.................. 38.1.3 Discotic Liquid Crystals ...............
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38.2 The Basic Physics of Liquid Crystals........ 38.2.1 Orientational Order ................... 38.2.2 Director Alignment .................... 38.2.3 Elasticity .................................. 38.2.4 Flexoelectricity.......................... 38.2.5 Viscosity ...................................
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38.3 Liquid-Crystal Devices .......................... 38.3.1 A Model Liquid-Crystal Display: Electrically Controlled Birefringence Mode (ECB) ........... 38.3.2 High-Volume Commercial Displays: The Twisted Nematic (TN) and Super-Twisted Nematic (STN) Displays............................ 38.3.3 Complex LC Displays and Other Cell Configurations .....
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38.4 Materials for Displays........................... 38.4.1 Chemical Structure and Liquid-Crystal Phase Behaviour .. 38.4.2 The Formulation of Liquid-Crystal Display Mixtures 38.4.3 Relationships Between Physical Properties and Chemical Structures of Mesogens ..............
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References .................................................. 949 references are given, but reference is also made to more extensive reviews where additional data are available.
38.1 Introduction to Liquid Crystals Liquid crystals have been known for almost 120 years but it is only in the last 30 years or so that their unique application in display devices has been recognised. Now they are seen as extremely important materials having made possible the development of thin screens for use with personal computers (PCs) and in televisions. In
fact a wide range of different liquid-crystal (LC) display devices has been developed. The common feature for each of these is that the optical characteristics of the display are changed on application of an electric field across a thin liquid-crystal film. The process causing this change is associated with a variation in the
Part D 38
This chapter outlines the basic physics, chemical nature and properties of liquid crystals. These materials are important in the electronics industry as the electro-optic component of flat-panel liquid-crystal displays, which increasingly dominate the information display market. Liquid crystals are intermediate states of matter which flow like liquids, but have anisotropic properties like solid crystals. The formation of a liquid-crystal phase and its properties are determined by the shape of the constituent molecules and the interactions between them. While many types of liquid-crystal phase have been identified, this Chapter focuses on those liquid crystals which are important for modern displays. The electro-optical response of a liquid crystal display depends on the alignment of a liquidcrystal film, its material properties and the cell configuration. Fundamentals of the physics of liquid crystals are explained and a number
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