熱敏感性光散亂效應

Thermal-sensitivity light scattering effect

梁世昌(Shih Chang LIANG)

指導教授 ： 黃振球

元智大學/工程學院/化學工程與材料科學學系/碩士(1997年)

摘要

利用兩種nematic低分子液晶混合從誘導出smectic相；然後再混合一種
cholesteric液晶(CB15)具有光學旋光性chiral的低分子液晶，我們將利
用上述的三成份液晶複合系做其相行為與光學性質研究。三成份液晶複合
系包含三種形式的Ch相、smectic相、M相、BP相與K相。藉著誘發smectic
相與Ch相的熱轉移來產生光學效果。本實驗不需偏光板和配向處理，只利
用熱轉移來達成光散亂與光透明的現象，使液晶面板會隨著溫度的不同而
呈現明暗的變化。這實驗是對三種低分子液晶複合系做熱光學特性研究，
並討論CB15的含量對複合系液晶相和熱光學特性的影響。本研究的目的是
研究溫度感應的光散亂效應，在某一溫度以下是光透明的高透光狀態，某
一溫度以上是光散亂狀態的低透光狀態，相轉移時透過光產生激烈變化，
低透過光的光散亂可由液晶相的螺旋節距與細微的條紋來實現；高透光狀
態可以由homeotropic排列的smectic A來達成。這種液晶元件不需要配向
、偏光板，期待應用於光柵、窗簾、辦公室、百貨公司的玻璃櫥窗等。

關鍵字

液晶 ； 光散亂 ； 誘導層列相 ； 熱光學效應 ； 光透過 ； 混濁

並列摘要

We are to study the phase behavior and optical nature by using
two kinds of nematic low-molecular liquid crystal mixture to
induce smectic phase and then mixing it with cholesteric liquid
crystal (CB15, one kind of low-molecular liquid crystal with
optical chiral feature). These three ingredients of liquid
crystal composites contains cholesteric phase, smectic phase,
M phase, blue phase and crystalline state. By inducing heart
transition from smectic phase and cholesteric phase we reach the
optical effect. This research does not mark use of electrical
field and optical polarizer but heat transition to reach the
effect of light scattering and light transparency which is
resulted from different temperature heated on the liquid crystal
display. This research studies the heat optical nature of these
three low-molecular liquid crystal composites and the effect of
different doses of CB15 applied on composites liquid crystal
phase and thermal-optical nature. This research is intended to
study the light scattering effect under different temperature
range. While under a certain level of temperature the high light transparency state is reached, the opaque state is resulted from above certain temperature level. Phase transition changes rapidly with light and light scattering effect from low transparecy is realized with the chiral pitch(or focal conic) texture of liquid crystal phase, while high light transparency state is reached with smectic A which is lined up with homeotropic. This kind of liquid crystal unit does not require rubbind treatment, optical polarizer, and is expected to be applied on blind and glass windows in the office or at the department store.

並列關鍵字

liquid crystal ； light scattering ； induced smectic ； thermo-optic effect ； transparent ； opaque

參考文獻

4. Katsumi Kondo, Atsuo Fukuda and Eiichi Kuze, 1981, Jpn. J. Appl. Phys., 20, 1779.

6. W. Kuczynski and H. Stegemeyer, 1995, Mol. Cryst. Liq. Cryst., 260, 377.

9. A. J. Slaney and J. W. Goodby, 1991, Liq. Cryst., 9, 849.

16. J. C. Hwang, Hirotsugu Kikuchi, and Kajiyama, 1995, Polymer, 27.292.

17. J. C. Hwang, and Y. C. Tsai, 1997, Jpn. J. Appl. Phys., 36, 2214.