Fundamental Study of Ferroelectric Liquid Crystals for their Practical Use in Fast Displays

研究了SSFLC态的结构和它们之间的转换过程。使用频闪显微照片观察开关过程对于澄清结构非常有用。在大多数情况下，Sm A作为高温相存在，上半部分晶胞的指向矢和下半部分晶胞的指向矢以相反的方向在圆锥上旋转;因此，中间的指向矢由于对称性要求而不能连续移动，从而突然跳跃，形成向错环。发生的开关过程的特点是内部向错的形成不可避免地需要在边界面的C-董事的选择性预倾斜。Clark和Lagerwall最初提出的更简单的切换过程，即所有指向矢都以相同的方向移动，虽然有时会发生，但相当例外。考虑到Clark等人的高分辨率X射线衍射研究，C-指向矢选择性预倾斜的真实的原因必须是近晶层的弯曲或扭结。层扭结有两种方式，即&lt;&lt;< and >&gt;&gt;。迄今为止，我们认为是由向错修饰的位错的锯齿形缺陷线，现在被认为是层结的错位，如&lt;&lt;*&gt;*&lt;&lt;。这种识别成功地解释了在开关过程中曲折线所起的特征作用。用光谱仪和偏光显微镜相结合的方法获得了SSFLC态的偏振透射光谱。基于层弯曲或C指向矢选择性预倾斜，我们可以用4 × 4矩阵方法近似地再现光谱。关于研究方案中所述的倾斜角的实验尚未进行，但已经提出了一种测量粘度常数的方法。在Sm A不作为高温相存在的情况下也进行了初步研究。

The structure of SSFLC states and the switching processes among them have been studied. Observation of the switching processes using stroboscopic micrographs was very useful for clarifying the structure. In most cases where Sm A exists as a high temperature phase, directors in the upper half of a cell and those in the lower half rotate on a cone in the opposite sense; hence the director in the middle which cannot move continuously because of the symmetry requirement make a sudden jump, forming a disclination loop. Occurrence of the switching process characterized by the internal disclination formation inevitably requires selective pretilting of the C-directors at the bounding surfaces. The simpler switching process originally proposed by Clark and Lagerwall, where all directors move in the same sense, is rather exceptional, though sometimes occurs.Taking account of the high resolution X ray diffraction study by Clark et al., the real cause of the C-director selective pretilting must be the bending or kinking of the smectic layers. There are two ways in which the layers kink, i.e. <<< and >>>. Zigzag defect lines so far considered by us as dislocations decorated by disclinations are now identified as the misarrangement of the layer kinks, such as <<<*>>>*<<<. This identification successfully explains the characteristic features played by the zigzag lines during the switching processes.Polarized transmittance spectra of the SSFLC states have been obtained by combining a spectrometer with a polarizing microscope. Based on the layer bending or the C-director selective pretilting, we can nearly reproduce the spectra using the 4 x 4 matrix method. Experiments concerning the tilt angle described in the research proposal has not been performed, but instead a noble method has been proposed for measuring the viscosity constants. Preliminary studies have also been done in a case where Sm A does not exist as a high temperature phase.