|
A blue phase mode LCD is a liquid crystal display (LCD) technology that uses highly twisted cholesteric phases in a blue phase. It was first proposed in 2007 to obtain a better display of moving images with, for example, frame rates of 100–120 Hz to improve the temporal response of LCDs.〔H. Kikuchi, et al., Fast Electro-Optical Switching in Polymer-Stabilized Liquid Crystalline Blue Phases for Display Application, SID07 Digest, pp. 1737-1740〕 This operational mode for LCDs also does not require anisotropic alignment layers (e.g., rubbed polyimide) and thus theoretically simplifies the LCD manufacturing process. ==History== In Reinitzer's reports from 1888 on the melting behaviour of cholesteryl benzoate, there is a note that the substance briefly turned blue as it changed from clear to cloudy upon cooling. This subtle effect remained unexplored for more than 80 years until experimental results were published during the late 1960s and early 1970s that indicated that the blue color was due to at least two new and very different liquid crystalline phases.〔Timothy J. Sluckin, David A. Dunmur, Horst Stegemeyer: Crystals That Flow - Classic Papers from the History of Liquid Crystals, Liquid Crystals Series, Taylor & Francis London 2004, ISBN 0-415-25789-1〕 For almost 100 years, scientists assumed that the most stable cholesteric helical structure could be described by a single helical axis about which the director rotates. It turned out that in the new structure the director rotates in a helical fashion about any axis perpendicular to a line as illustrated in fig. 1. Although an unlimited number of helical axes are actually present, this structure was named ''double twist structure''. This ''double twist structure'' is more stable than the ''single twist structure'' (i.e., the normal helical structure of chiral nematics) only up to a certain distance from the line at the center. Since this distance is on the order of the pitch of the chiral nematic liquid crystal (typically 100 nm) and since the geometries of usual liquid crystal samples are much larger, the ''double twist structure'' occurs only rarely. Blue phases are special cases when double twist structures fill up large volumes. When double twist structures are limited in all directions to the distance from the center line where the twist amounts to 45° a ''double twist cylinder'' results. Because of its small radius, such a cylinder is more stable than the same volume filled with a single twist chiral nematic liquid crystal. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Blue phase mode LCD」の詳細全文を読む スポンサード リンク
|