藍相液晶盒厚度與克爾常數相依關係之研究

The relationship between the Kerr constant and cell thickness in blue phase liquid crystal cells

蔡欣言(Sin-Yan Tsai)

指導教授 ： 吳俊傑

共同指導教授 ： 陳殿榮

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2014年)

摘要

藍相液晶( Blue phase liquid crystal )是一個擁有雙螺旋柱體( Double twist cylinder )晶格結構的液晶分子，其光電機制是當施予外加電場時，會誘發雙折射現象，也就是克爾效應( Kerr effect )，因此我們所討論的液晶盒厚度造成克爾常數的改變，對於觀察藍相液晶的光電特性也是重要的參考，並對於未來應用在藍相液晶顯示器相關產品上相當有幫助。
在本論文中，我們使用不同厚度的藍相液晶盒，經由垂直場驅動，液晶盒擺放在與入射光夾45° 與60° 的位置，量測出在斜向入射光下的相位φ跟電壓V關係，並利用相位公式求得雙折射δn。最後，我們再根據克爾效應的公式進行整理，得到在低電場時雙折射δn會與外加電場平方E^2 呈現線性關係，此實驗結果與理論值相符。求得克爾常數後，可以發現不同的液晶盒厚度會對克爾常數造成影響。

關鍵字

藍相液晶 ； 克爾效應

並列摘要

Blue phase liquid crystal ( BPLC ) has a double helical cylinder lattice structure. The electro-optical mechanism of BPLC is the electric-field-induced birefringence, δn, known as the Kerr effect. In this study, we experimented and discussed the relation between the Kerr constant and cell thickness. The result is an important reference for BPLC electro-optical property, and may have a great help for applications of BPLC in the future.
In this paper, we changed the thickness of the cell and drove it by vertical electric field. The BPLC cells were placed in 45? and 60? with respect to the incident light. Measuring the relationship between the phase retardation φ and driving voltage V, and using the φ - V relation, we obtained the induced birefringence δn. Finally, we obtained that the δn is proportional to E^2. The results match the Kerr effect formula. Kerr constant is calculated, and we found that the cell thickness will affect the Kerr constant.

並列關鍵字

blue phase liquid crystal ； Kerr effect

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