STUDIES ON MOLECULAR ALIGNMENT MODEL IN NEMATIC LIQUID CRYSTALS EMPLOYING DYNAMICAL IMAGE-PROCESSING TECHNOLOGY

利用动态图像处理技术研究向列液晶分子排列模型

基本信息

批准号：
61550036
负责人：
YAMASHITA Masafumi
金额：
$ 1.15万
依托单位：
Science University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

The dynamical changes of the conoscopic figures and the interference intensities in the twisted nematic liquid crystal (LC) film with twisted angle of 90 degrees were measured to analyze the dynamical changes of the LC molecular alignments after the electric field composed of a small number of altemating pulsed were removed with the use of an image-processing technology and the single or double block pulse method. The details of the experimental results were studied. Some new physical phenomena were found. 1. The changes of the LC molecules continue aligning for a fes milliseconds after the electric field is removed. This is called the lagging changes of the LC molecular alignments. 2. The time required to show the maximum intensities of the conoscopic figures after the electric field is applied is almost the same regardless of the applied manners. It is considered by the numerical calculation derived from a modified Voigt model in the viscoelastic theory combining the theory of an altemating current circuit that the floating capacity, the viscosity resistance and electric deformations of the LC molecules have effects upon the lagging changes. 3. The changing rate of deformations of the LC alignments is estimated by the Voigt model with changing the ratio of the coefficient of viscisity to the elastic modulus as a function of the distance from the film surfaces instead of considering the effect of the anchoring force. We can represent the equation of the changing rate exponentially. 4. The method of computer simulations to obtain the conoscopic figures was developed on the basis of crystal optics.

测量了90°扭曲向列液晶薄膜锥光图形和干涉强度的动态变化，分析了少量交替电场作用后液晶分子排列的动态变化。使用图像处理技术和单块或双块脉冲方法去除脉冲。研究了实验结果的细节。发现了一些新的物理现象。 1. 电场移除后，LC 分子的变化继续排列 1fes 毫秒。这称为液晶分子排列的滞后变化。 2.无论采用何种施加方式，施加电场后显示锥光图形最大强度所需的时间几乎相同。结合交流电路理论，对粘弹性理论中修正的Voigt模型进行数值计算，认为液晶分子的浮动电容、粘阻和电变形对滞后变化有影响。 3.通过Voigt模型估计LC排列变形的变化率，改变粘度系数与弹性模量的比值作为距薄膜表面距离的函数，而不考虑锚固力的影响。我们可以用指数表示变化率的方程。 4、在晶体光学的基础上发展了锥光图形的计算机模拟方法。