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Chin. Opt. Lett.
 Home  List of Issues    Issue 08 , Vol. 15 , 2017    10.3788/COL201715.081203


Entanglement-free determination of pretilt angles of twisted nematic liquid-crystal cells by phase measurement
Che-Wen Chiang1, Ping-Chun Lin2, and Kei-Hsiung Yang2
1 Institute of Photonic System, [National Chiao Tung University], Tainan City 71 1 50, China
2 Institute of Imaging and Biomedical Photonics, [National Chiao Tung University], Tainan City 71105, China

Chin. Opt. Lett., 2017, 15(08): pp.081203

DOI:10.3788/COL201715.081203
Topic:Instrumentation, measurement and metrology
Keywords(OCIS Code): 120.0120  220.0220  

Abstract
The pretilt angle of a twisted nematic (TN) liquid crystal display has a strong effect on viewing angles and response times of the display as well as shifting the light-leaking disclination lines into the black-matrix area within pixels of a thin-film-transistor driven TN panel for a high contrast ratio. In this Letter, we develop an optical method to determine the TN pretilt angle based on heterodyne measurements of the phase versus the incident angle of a thin TN cell subjected to out-of-plane rotations. We believe that our method of measuring phases has advantages of simpler setup and calculations, better stability, and less sensitive to ambient electromagnetic interference than the commonly used method of measuring intensities.

Copyright: © 2003-2012 . This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Received:2017/4/19
Accepted:2017/5/19
Posted online:2017/6/13

Get Citation: Che-Wen Chiang, Ping-Chun Lin, and Kei-Hsiung Yang, "Entanglement-free determination of pretilt angles of twisted nematic liquid-crystal cells by phase measurement," Chin. Opt. Lett. 15(08), 081203(2017)

Note: We acknowledge financial support from LAWS’ Tech Co., LTD. and several useful discussions with Dr. Sheng-Ya Wang.



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