向列相液晶弹性各向异性诱导液晶盒产生漏光的研究

王永超; 张志东; 周璇

doi:doi:10.3788/yjyxs20153006.0949

液晶与显示, 2015, 30 (6): 949, 网络出版: 2016-01-19

向列相液晶弹性各向异性诱导液晶盒产生漏光的研究

Study of light leakage induced by the elastic anisotropy of the nematic liquid crystal

论文大纲

王永超 ^*张志东周璇

作者单位

河北工业大学理学院，天津300401

体缺陷结构漏光 Landau-de Gennes 理论自发扭曲形变 bulk defect structure light leakage Landau-de Gennes theory spontaneous distortion

摘要

为了阐述具有体缺陷结构的向列相液晶盒在暗态出现漏光的原因，以及边界锚定条件对漏光的影响，首先，建立了3个向列相液晶盒模型，它们具有不同的初始指向矢排布。接着，基于Landau-de Gennes理论，通过对指向矢场的缺陷动力学计算，得到液晶盒截面内平衡态的指向矢分布。最后，使用琼斯矩阵法将该截面内的指向矢分布以透过率的形式表示出来。模拟结果显示，在无外场条件下，当向列相液晶的弹性常数满足L2/L1≥ 1 (K22/K11≤ 2/3)时，具有体缺陷结构的液晶盒展现出了自发的扭曲结构，导致了漏光的出现。且漏光强度随着缺陷结构和边界条件的不同而不同。本文模型很好地解释了体缺陷造成液晶盒在暗态出现漏光的原因，且模拟结果与工业生产过程中观察到的现象是一致的。

Abstract

In the paper, we show the reasons for light leakage in the nematic liquid crystal (NLC) cells with bulk defect structure in the dark state and the influence of the anchoring conditions on it. Firstly, we give three models of NLC cells with different director distribution at the initial state. Secondly, based on the Landau-de Gennes theory, we calculate the defect dynamics of the director field and get the director distribution in the cross-section of the cells at equilibrium state. Finally, we express the director distribution in the form of light transmittance with Jones Calculus. Without applied field, the simulation results indicate that the cells with bulk defect have spontaneous twist structure under the condition of L2/L1≥ 1 (K22/K11≤ 2/3), which leads to light leakage of the cells. The intensity of light leakage varies with defect structures and anchoring conditions at the boundaries. Our models can explain the light leakage in the NLC cells induced by the bulk defect in the dark state, and the results show a good agreement with the phenomena found in the process of industry manufacture.

参考文献

[1] Jeong J, Davidson Z S, Collings P J, et al. Chiral symmetry breaking and surface faceting in chromonic liquid crystal droplets with giant elastic anisotropy [J]. Proceedings of the National Academy of Sciences of the United States of America, 2014, 111(5): 1742-1747.

[2] Williams R D. Two transitions in tangentially anchored nematic droplets [J]. Journal of Physics A: Mathematical and General, 1986, 19(16): 3211-3222.

[3] Lavrentovich O D, Sergan V V. Parity-breaking phase transition in tangentially anchored nematic drops [J]. II Nuovo Cimento D, 1990, 12(9): 1219-1222.

[4] Xu F, Kitzerow H S, Crooker P P. Director configurations of nematic-liquid-crystal droplets: Negative dielectric anisotropy and parallel surface anchoring [J]. Physical Review E, 1994, 49(4): 3061-3068.

[5] Drzaic P S. A case of mistaken identity: spontaneous formation of twisted bipolar droplets from achiral nematic materials [J]. Liquid Crystals, 1999, 26(5): 623-627.

[6] Atherton T J, Sambles J R. Orientational transition in a nematic liquid crystal at a patterned surface [J]. Physical Review E, 2006, 74(2): 022701.

[7] Kléman M. Points, Lines and Walls: in Liquid Crystals, Magnetic Systems and Various Disordered Media [M]. New York: Wiley, 1983.

[8] Denniston C, Yeomans J M. Flexoelectric surface switching of bistable nematic devices [J]. Physical Review Letters, 2001, 87(27): 275505.

[9] Varghese S. Patterned Alignment of Liquid Crystals by Microrubbing: A New Route Towards Wide Viewing Angle Flat Panel Displays [M]. Eindhoven: Technische Universiteit Eindhoven, 2005.

[10] 王海成，董天松，郑英花，等.TFT-LCD制程中Zara点状不良的产生与改善研究[J].液晶与显示，2013,28（5）：707-710.

Wang H C, Dong T S, Zheng Y H, et al. Occurrence and improvement of Zara particle in TFT-LCD cell process [J]. Chinese Journal of Liquid Crystals and Displays, 2013, 28(5): 707-710. (in Chinese)

[11] De Gennes P G, Prost J. The Physics of Liquid Crystals [M]. Oxford: Clarendon Press, 1993.

[12] Choi Y H, Kim K, Ji S, et al. Multidimensional simulation of the defect in the liquid crystal director field from Inhomogeneous patterned electrodes by using the fast Q-tensor method [J]. Journal of the Korean Physical Society, 2007, 51(5): 1700-1706.

[13] Se D, Porenta T, Ravnik M, et al. Geometrical frustration of chiral ordering in cholesteric droplets [J]. Soft Matter Physics, 2012, 8(48): 11982-11988.

[14] Kang W S, Joo W Y, Hur S Y, et al. Effect of the surface anchoring energy on modeling the defect in the liquid crystal director field [J]. Journal of the Korean Physical Society, 2010, 57(4): 752-755.

[15] Zhou X, Zhang Z D. Dynamics of order reconstruction in nanoconfined twisted nematic cells with a topological defect. Liquid Crystals, 2014, 41(9): 1219-1228.

[16] Virga E G. Variational Theories for Liquid Crystals [M]. London: Chapman, 1994.

[17] Kleman M, Lavrentovich O D. Soft Matter Physics [M]. Berlin: Springer, 2002.

[18] Spencer T J, Care C M. Lattice Boltzmann scheme for modeling liquid-crystal dynamics: Zenithal bistable device in the presence of defect motion [J]. Physical Review E, 2006, 74(6): 061708.

[19] Lombardo G, Ayeb H, Barberi R. Dynamical numerical model for nematic order reconstruction [J]. Physical Review E, 2008, 77(5): 051708.

[20] Kralj S, Rosso R, Virga E G. Finite-size effects on order reconstruction around nematic defects [J]. Physical Review E, 2010, 81(2): 021702.

[21] Zhou X, Zhang Z D. Dynamics of order reconstruction in a nanoconfined nematic liquid crystal with a topological defect [J]. International Journal of Molecular Sciences, 2013, 14(12): 24135-24153.

[22] Guzmán O, Abbott N L, De Pablo J J. Quenched disorder in a liquid-crystal biosensor: Adsorbed nanoparticles at confining walls [J]. The Journal of Chemical Physics, 2005, 122(18): 184711.

[23] Jérme B. Surface effects and anchoring in liquid crystals [J]. Reports on Progress in Physics, 1991, 54(3): 391-451.

[24] Luckhurst G R, Miyamoto T, Sugimura A, et al. The surface-induced static director distribution in thin nematic liquid crystal films: A deuterium nuclear magnetic resonance spectroscopy study [J]. The Journal of Chemical Physics, 2001, 114(23): 10493-10503.

[25] 吴诗聪. 液晶材料与应用 [J]. 现代显示，1995(2):25-31,16.

Wu S C. Materials and application of liquid crystal [J]. Advanced Display, 1995(2): 25-31, 16. (in Chinese)

王永超, 张志东, 周璇. 向列相液晶弹性各向异性诱导液晶盒产生漏光的研究[J]. 液晶与显示, 2015, 30(6): 949. WANG Yong-chao, ZHANG Zhi-dong, ZHOU Xuan. Study of light leakage induced by the elastic anisotropy of the nematic liquid crystal[J]. Chinese Journal of Liquid Crystals and Displays, 2015, 30(6): 949.

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