外加电压频率对液晶介电各向异性的影响
Influence of the frequency of external applied voltage on the dielectric anisotropy of liquid crystal
摘要
Abstract
The dielectric anisotropy of liquid crystal materials is usually related to the frequency.For further investigations of the influence of frequency on the dielectric constant of liquid crystal materials,firstly,the thickness of the liquid crystal cells and the thickness of the polymide(PI)ori-entation layers were measured by UV spectrophotometer(METASH UV-9000S)and Surface Profiler (Contor GK-T)respectively.The precision hot-stage(LTS 350)was used to control the experimental temperature of 20 ℃,and the capacitance of parallel and vertical aligned nematic liquid crystal cells were measured by a precision LCR meter(Agilent E4980A)at the frequency of 100~2 000 Hz for four different liquid crystal materials.Then,the parallel and vertical dielectric constants of liquid crystals at different frequencies were calculated through the capacitance model of LC cell,the curves of dielectric constant versus frequency were plotted as well.Finally,the influence of the frequency of external applied voltage on the dielectric anisotropy of liquid crystal was analyzed.The experimental results showed that the dielectric anisotropy of the positive liquid crystal decreased with the increase of the frequency at a certain temperature first,and then gradually flatten out,w hile dielectric anisotropy of negative liquid crystal remained unchanged with the change of frequency.This research has a guid-ing significance for further analysis of the dielectric characteristics of liquid crystal materials.关键词
液晶盒电容模型/介电各向异性/频率/电容Key words
LC cell capacitance model/dielectric anisotropy/frequency/capacitance分类
数理科学引用本文复制引用
戴亚雨,高林,庞泽,李振杰,蔡明雷,王晓燕,朱吉亮,叶文江..外加电压频率对液晶介电各向异性的影响[J].液晶与显示,2018,33(3):175-181,7.基金项目
国家自然科学基金(No.11374087 （）
No.11504080) （）
河北省自然科学基金(No.A2014202123 （）
No.A2017202004) （）
河北省教育厅项目(No.QN2014130) （No.QN2014130）
河北省高等教育教学改革研究与实践项目(No.2017GJJG018) （No.2017GJJG018）
大学生创新创业训练计划项目(No.20170080289) （No.20170080289）
河北省高校重点学科资助课题Supported by National Natural Science Foundation of China(No.11374087 and 11504080) （No.11374087 and 11504080）
Natural Science Foundation of Hebei Province(No.A2014202123 and A2017202004) （No.A2014202123 and A2017202004）
Research Project of Hebei Education Department(No.QN2014130) （No.QN2014130）
Research and practice project of Hebei Province Higher Education and Teach-ing Reform(No.2017GJJG018) （No.2017GJJG018）
Project of College Students＇Innovation and Entrepreneurship Training Program(No.20170080289) （No.20170080289）
Key Subject Construction Project of Hebei Province University． （）
