Comparison of Vertically Aligned, Electronically Controlled Birefringence (ECB) and In-Plane-Switching Liquid Crystal Operation Modes: Optical Performance and Topological Defects

Shih-Yu Chao¹, Sheng-Kai Yao^1*, Jing-Kai Chou¹, Jing-Ting Chen¹, Chia-Pei Hsieh¹, Wei-Yuan Chen², Ting-Mao Fung², Tsung-Hsien Lin², Jieh-Wen Tsung¹

¹Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
²Department of Photonics, National Sun Yat-sen University, Kaohsiung, Taiwan

* Presenter:Sheng-Kai Yao, email:skyao.ep09g@nctu.edu.tw

In the research, we analyze and compare the Vertically aligned (VA), ECB and In-Plane-Switching (IPS) liquid crystal (LC) operational modes, which includes the LC director field and optical performance of VA and IPS test cells. We use patterned Indium Tin Oxide (ITO) transparent electrodes to control the LC director and topological defects. We use polarizing optical microscope (POM) with crossed analyzer and polarizer and a lambda-wave plate on the diagonal direction are applied to derive the LC director field by the birefringence colors. In addition, transmittance versus applied voltage (Tr.-V) was directly extracted from the POM image with the help from the analysis software, Image J, which is our special technique. The Tr.-V of the VA, ECB and IPS mode cells are directly compared.

Keywords: nematic liquid crystal, liquid crystal operation mode, topological defect