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

개선된 투과형 타원계를 사용한 러빙된 Polyimide 배향막의 초미세 위상지연 정밀 측정

  • 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)
  • 염경훈 (아주대학교 분자과학기술학과) ;
  • 박상욱 ((주)엘립소테크놀러지) ;
  • 양성모 (아주대학교 분자과학기술학과) ;
  • 윤희규 (아주대학교 분자과학기술학과) ;
  • 김상열 (아주대학교 분자과학기술학과)
  • Received : 2013.02.13
  • Accepted : 2013.03.28
  • Published : 2013.04.25


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.


Grant : 초미세 광학이방성 측정장비의 개발 및 LCD 배향막의 이방성 분포 연구

Supported by : 한국연구재단


  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.
  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).
  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).
  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).
  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).
  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).
  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).
  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).
  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).
  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).
  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).
  14. 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.
  15. 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).

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