液晶可调电容器的研究  

Liquid Crystal Tunable Capacitor

作　　者：崔文静[1] 邢红玉[1,2,3] 叶文江[1] 张志东[1] 

机构地区：[1]河北工业大学理学院,天津300401 [2]中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,吉林长春130033 [3]中国科学院大学,北京100049

出　　处：《液晶与显示》2013年第2期173-178,共6页Chinese Journal of Liquid Crystals and Displays

基　　金：国家自然科学基金(No.10974042;No.11147103;No.11274088);河北省自然科学基金(No.A2010000004);河北省教育厅项目(No.Z2012061;No.Z2011133);河北省高校重点学科资助项目

摘　　要：在外加电压作用下,液晶的有效介电常数会发生变化,导致液晶盒电容的改变,由于液晶盒本身可以看作是一个电容器,因此随着外加电压的不同其电容是可调的。基于液晶弹性理论和变分原理,理论推导强锚泊平行排列和混合排列向列相液晶盒电容的解析表达式,数值模拟得到了液晶盒的电容-电压曲线。通过数据分析,两种液晶盒的电容特性存在一定的区别,尤其在较低电压时为了获得较大范围的可调液晶电容器,平行排列盒选择弹性常数κ较小且介电各向异性γ较大的液晶材料;而混合排列盒选择弹性常数κ较大且介电各向异性γ较大的液晶材料。高压时两盒的选择是一致的。The effective dielectric constant of liquid crystal filled in this cell will change under an external applied voltage, which can result in the variation of the capacitance in liquid crys- tal cell. Because liquid crystal cell itself may be seen as a capacitor, its capacitance is tunable with different external applied voltages. Based on liquid crystal elasticity theory and varia- tional principles, the analytical expressions of the capacitance in strong anchoring parallel aligned nematic （PAN） and hybrid aligned nematic （HAN） liquid crystal cell are deduced theoretically. The capacitance-voltage curves of these two cells are also obtained by numeri- cal simulation. From the data analysis, there exist some differences for the capacitance characteristics between the two types of cells, especially in the case of low voltage. To ob- tain the wide range tunable capacitance, the liquid crystal material with the smaller elastic constant and the larger dielectric anisotropic constant should be chose for-PAN cell; however, for HAN cell, the situation is reversed. When a high voltage is applied to the liquid crystal cell, the choice of liquid crystal material for two types of cells is consistent.

关 键 词：液晶可调电容器 有效介电常数 平行排列向列相 混合排列向列相 

分 类 号：TM532.5[电气工程—电器]