The reflective optical properties of dye guest-host type cholesteric liquid crystals

• Main Authors: Ying-Chang Chiu, 邱英彰
• Other Authors: Jiunn-Yih Lee
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/82844523302246086119

碩士 === 國立臺灣科技大學 === 纖維及高分子工程系 === 90 === In this study, we proposed a novel dye mixed cholesteric liquid crystals devices. Experimentally, first, utilizing the nematic liquid crystal with cholesteric liquid crystal, we’ll be able to produce a cholesteric liquid crystal with a reflection wavelength in visible region. We found that the helical pitch of temperature sensitive cholesteric liquid crystal would change with the changing of temperature, and its reflectivity would have obviously changed as well. The reflectivity of cholesteric liquid crystal would not disappear due to the slow temperature rising until approach to isotropic temperature closely. To follow the temperature increase, the reflection wavelength shift to short wavelength region. After that we add dichroic dye to temperature sensitive cholesteric liquid crystal to produce dye guest-host type cholesteric liquid crystal devices. Light entering the liquid crystal is absorbed by the dye generating heat, which raises the temperature of the liquid crystal, the change of temperature caused the shift of reflective wavelength. The effect of temperature on helical pitch and reflective of helical pitch were discussed herein. When the content of dye increases, the wave of reflectivity will change. If add incident light, the wave of reflectivity changes remarkably, too.