The Optical Properties of Cholesteric Liquid Crystals Doped with Dye

• Main Authors: Jen-I Hsiao, 蕭仁義
• Other Authors: Jiunn-Yih Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/20356549840469744334

碩士 === 國立臺灣科技大學 === 高分子工程系 === 91 === Firstly, we mixed nematic liquid crystal with cholesteric liquid crystal to produce a liquid crystal that have two mesophases: Smectic A and Cholesteric. The reflection wavelength of the cholesteric liquid crystal is in visible region. We found the pitch will be shortened during gaining the ambient temperature and the reflection wavelength shifts to short wavelength region. After cholesteric liquid crystal doping with a Methyl Red dye, the dye is pumped by Ar laser and the reflectivity is probed by He-Ne laser. We found the reflectivity increases with gaining laser power, but the reflectivity won’t increase when laser power is too high. Conceivably Methyl Red dye occurred trans-cis transition after pumped by Ar laser, cause unhomogeneous planar texture of cholesteric liquid crystal. This investigation could be applied as optically switched display devices.