Browse > Article
http://dx.doi.org/10.3807/KJOP.2013.24.2.077

Precise Measurement of Ultra Small Retardation of Rubbed Polyimide Alignment Layer Using an Improved Transmission Ellipsometer  

Lyum, Kyoung Hun (Department of Molecular Science and Technology, Ajou University)
Park, Sang Uk (Ellipso Technology Co., Ltd.)
Yang, Seong Mo (Department of Molecular Science and Technology, Ajou University)
Yoon, Hee Kyu (Department of Molecular Science and Technology, Ajou University)
Kim, Sang Youl (Department of Molecular Science and Technology, Ajou University)
Publication Information
Korean Journal of Optics and Photonics / v.24, no.2, 2013 , pp. 77-85 More about this Journal
Abstract
The precision of retardation measurement has been improved upto $3{\sigma}$ <0.005 nm after improvements are made to the conventional transmission ellipsometer. Improvements are made such that, i) the polarizer module instead of the sample stage is rotated, ii) the light source is replaced, iii) the starting points of two rotating modules are accurately synchronized, and iv) the fine background retardation is compensated. Together with the newly introduced RVD (Retardation Vector Difference) method, the improved instrument is successfully applied to characterize the ultra small optical birefringence of the rubbed polyimide alignment layer, after the residual retardation due to glass substrate whose magnitude is about 1.0 nm is properly subtracted. It is verified that the net retardation of the alignment layer ranges from 0.05 nm to 0.15 nm.
Keywords
Ellipsometry; Retardation; Rubbed polyimide; Alignment layer; Anisotropy;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
연도 인용수 순위
1 S.-Y. Kim, "The study of photo-sensitive polyimide containing methoxy cinnamate derivatives on photoalignment of liquid crystal," M.S. Thesis, Hongik University, Seoul (2011).
2 S. U. Park, S. Y. Kim, and K. H. Lyum, "Precise measurement of ultra small optical anisotropy and substrate effect to LCD alignment layer versus rubbing strength by using transmission ellipsometry," IMID 2011 Program, 51-3.
3 http://www.ellipsotech.com/Ellipsometer_02.html.
4 G. Fang, J. Maclennan, and N. Clark, "High extinction polarimeter for the precision measurement of the in-plane optical anisotropy of molecular monolayers," Langmuir 26, 11686-11689 (2010).   DOI   ScienceOn
5 H. R. Kim and S. Y. Kim, "Precise measurement of optical anisotropy of rubbed polyimide on patterned glass and its nanoscale variation," Korean J. Opt. Photon. (Hankook Kwanghak Hoeji) 20, 281-287 (2009).   과학기술학회마을   DOI   ScienceOn
6 J. W. Ryu and S. Y. Kim, "Analysis of effective optic axis and equivalent retardation of composite optically anisotropic film by using transmission ellipsometry," Korean J. Opt. Photon. (Hankook Kwanghak Hoeji) 20, 288-293 (2009).   과학기술학회마을   DOI   ScienceOn
7 C. Benecke, H. Seiberle, and M. Schadt, "Determination of director distribution in liquid crystal polymer-films by means of generalized anisotropic ellipsometry," Jpn. J. Appl. Phys. 39, 525-531 (2000).   DOI
8 J. A. Ekhoff, M. J. Farrow, D. M. Walba, and K. L. Rowlen, "Molecular orientation of a model liquid crystal alignment layer," Talanta 60, 801-808 (2003).   DOI   ScienceOn
9 J. W. Ryu, S. Y. Kim, and Y. K. Kim, "Determination of the optic axis distribution of a hybridly aligned discotic material for wide-view films," J. Korean Phys. Soc. 57, 233-239 (2010).   DOI   ScienceOn
10 C. Yu, J. Bae, C. M. Keum, and S. D. Lee, "Optical anisotropy of aligned pentacene molecules on a rubbed polymer corresponding to the electrical anisotropy," Current Applied Physics 10, 64-67 (2010).   DOI   ScienceOn
11 M. Yamahara, M. Nakamura, N. Koide, and T. Sasaki, "Influence of rubbing conditions of polyimide alignment layer on optical anisotropy of immobilized liquid crystal film," Liquid Crystals 34, 381-387 (2007).   DOI   ScienceOn
12 F. Yang, G. Zoriniants, L. Ruan, and J. R. Sambles, "Optical anisotropy and liquid-crystal alignment properties of rubbed polyimide layers," Liquid Crystals 34, 1433-1441 (2007).   DOI   ScienceOn
13 K. Ichimura, Y. Susuki, T. Seki, A. Hosoki, and K. Aoki, "Reversible change in alignment mode of nematic liquid crystals regulated photochemically by command surfaces modified with an azobenzene monolayer," Langmuir 4, 1214-1216 (1988).   DOI   ScienceOn
14 S.-H. Kang, K. Kim, J. Lee, B. Jeon, J. Yeom, and S.-R. Cho, "Method of forming alignment layer and fabrication method of liquid crystal display using the same," Patent KR-20120301983 (2012).
15 K. Miyachi, N. Kimura, Y. Yamada, and S. Mizushima, "The UV2A technology for large size LCD-TV panels," in Proc. The 17th International Display Workshops (Fukuoka, Japan, Dec. 2010), LCT1-1.