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Experimental design to measure the anchoring energy on substrate surface by using the alternating-current bridge 下载免费PDF全文
The anchoring property of the substrate surface of liquid crystal cells plays an important role in display and nondisplay fields. This property directly affects the deformation of liquid crystal molecules to change the phase difference through liquid crystal cells. In this paper, a test method based on the alternating-current bridge is proposed to determine the capacitance of liquid crystal cells and thus measure the anchoring energy of the substrate surface. The anchoring energy can be obtained by comparing the capacitance–voltage curves of twisted nematic liquid crystal cells with different anchoring properties in experimental and theoretical results simulated on the basis of Frank elastic theory. Compared with the other methods to determine the anchoring energy, our proposed method requires a simple treatment of liquid crystal cells and allows easy and high-accuracy measurements, thereby expanding the test ideas on the performance parameters of liquid crystal devices. 相似文献
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Azimuthal anchoring of a nematic liquid crystal on a grooved interface with anisotropic polar anchoring 下载免费PDF全文
Zhang Y J et al.[Zhang Y J,Zhang Z D,Zhu L Z and Xuan L 2011 Liquid Cryst.38 355] investigated the effects of finite polar anchoring on the azimuthal anchoring energy at a grooved interface,in which polar anchoring was isotropic in the local tangent plane of the surface.In this paper,we investigate the effects of both isotropic and anisotropic polar anchoring on the surface anchoring energy in the frame of Fukuda et al.’s theory.The results show that anisotropic polar anchoring strengthens the azimuthal anchoring of grooved surfaces.In the one-elastic-constant approximation(K11 = K22 = K33 = K),the surface-groove-induced azimuthal anchoring energy is entirely consistent with the result of Faetti,and it reduces to the original result of Berreman with an increase in polar anchoring.Moreover,the contribution of the surface-like elastic term to the Rapini-Papoular anchoring energy is zero. 相似文献
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We present a theoretical calculation of the dependence of reflectivity Rpp of the improved fully leaky waveguide geometry,which comprises pyramid,matching fluid,and strongly anchored hybrid aligned nematic liquid crystal(NLC) cell on the internal angle.The calculation is based on the multi layer optical theory and the elastic theory of liquid crystals.For different sums of flexoelectric coefficients e11 and e33,the curve of Rpp moves a distance to the left or the right relative to the case of ignoring the flexoelectric effect and the distance of the movement varies with different flexoelectric coefficients.Consequently,the sum of flexoelectric coefficients can be explored by measuring the distance of the movement. 相似文献
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The anchoring properties of substrate with a grating surface are
investigated analytically. The alignment of nematic liquid
crystal (NLC) in a grating surface originates from two
mechanisms, thus the anchoring energy consists of two parts. One
originates from the interaction potential between NLC molecules
and the molecules on the substrate surface, and the other stems
from the increased elastic strain energy. Based on the two
mechanisms, the expression of anchoring energy per unit area of
a projected plane of this grating surface is deduced and called
the equivalent anchoring energy formula. Both the strength and
the easy direction of equivalent anchoring energy are a function
of the geometrical parameters (amplitude and pitch) of a grating
surface. By using this formula, the grating surface can be
replaced by its projected plane and its anchoring properties can
be described by the equivalent anchoring energy formula. 相似文献
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基于迈克尔逊干涉原理设计了金属丝杨氏模量的测量装置。在金属丝上施加持续而又均匀增加的力,引起金属丝细微伸长,通过灵敏杠杆带动移动镜的移动,从而引起光屏上干涉圆环数目的变化;用一种光电传感器捕捉干涉圆环的光强信号,将光信号转换为电信号,再通过模数转换,精确算出干涉圆环的条数,就可以实现对金属丝微小伸长量的测量。采用Origin软件处理实验数据,避免了人为因素所造成的误差,智能化计算出金属丝的杨氏模量。 相似文献
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利用全漏光导波技术,测量负性向列相液晶材料MS-N01300-000的展曲和弯曲挠曲电系数之和.根据液晶弹性和多层光学理论得到同一电压下不同挠曲电系数的反射率随内角(入射到液晶层角度)的理论变化曲线.实验中,将液晶材料灌注到混合排列向列相液晶盒中,在液晶盒上分别加交流电和直流电,采用全漏光导波技术得到反映液晶指向矢分布的液晶波导反射率随内角变化曲线.实验发现,由于液晶挠曲电作用,同一电压值下反射率随内角变化曲线发生微小移动.对比理论与实验曲线,由曲线移动距离得到MS-N01300-000液晶材料展曲和弯曲挠曲电系数之和为2.5×10-11 C/m. 相似文献
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