• Title/Summary/Keyword: Rubbing Process

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High Performance OCB Panel Driven less than 5V for Multi-media Application

  • Chang, H.S.;Lee, C.H.;Ryu, J.J.;Kim, M.S.;Ahn, S.H.;Kim, K.H.;Kim, S.S.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.914-917
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    • 2002
  • We have obtained high performance and low voltage driving OCB panel by reducing the critical voltage and retardation matching between liquid crystal layer and compensation films. The critical voltage in the panel has been minimized by flattening color filter layer and optimizing a rubbing process. In addition, an appropriate retardation of the film and LC layer has scanned to achieve low driving voltage and high transmission. The proto-type 17" WXGA OCB panel has demonstrated with less than 5V drive and over 80 degree for all viewing direction except for rubbing direction with over 90% of TN light efficiency.

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Studies on the Synthesis of Bisphenol Sulfonate Polymers and Their Staining Resist Effect in the Dyeing of Nylon/Cotton Union (Ⅱ) (Bisphenol sulfone산계 고분자의 합성 및 나일론 오염방지성에 관한 연구 (Ⅱ))

  • Choe, Yeong Ju;Song, Seung Jong;Yun, Nam Sik
    • Textile Coloration and Finishing
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    • v.13 no.2
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    • pp.1-1
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    • 2001
  • In the Previous studies, we reported about the synthesis of poly[3-methylence-3-methylenesodiumbisulfite-bis(4-hydroxypheny)sulfone] (PMSBPS) and their effect on the staining of direct dye on nylon in the dyeing of nylon/cotton union. The results showed that PMSBPS have good staining resist effect on nylon in the dyeing of nylon/cotton union. In this study, the staining resist effects of PMSBPS in varied dyeing process and method were investigated, and the fastness to washing, light, and rubbing of the deed N/C unions was tested. The results are as follows ; 1. In the two bath two step method, the staining of direct dye on nylon was decreased with the concentration of PMSBPS, and the fastness to washing, light, and rubbing of the dyed N/C unions were increased by addition of PMSBPS. 2. In the one bath two step method, optimun concentration of PMSBPS was 4% 0.w.f..

Studies on the Synthesis of Bisphenol Sulfonate Polymers and Their Staining Resist Effect in the Dyeing of Nylon/cotton Union ( II ) (Bisphenol sulforn산계 고분자의 합성 및 나일론 오염방지성에 관한 연구 (II))

  • 최영주;송승종;윤남식
    • Textile Coloration and Finishing
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    • v.13 no.2
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    • pp.87-92
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    • 2001
  • In the Previous studies, we reported about the synthesis of poly(3-methylence-3-methylenesodiumbisulfite-bis(4-hydroxypheny )sulfone] (PMSBPS ) and their effect on the staining of direct dye on nylon in the dyeing of nylon/cotton union. The results shoved that PMSBPS have good staining resist effect on nylon in the dyeing of nylon/cotton union. In this study, the staining resist effects of PMSBPS in varied dyeing process and method were investigated, and the fastness to washing, light, and rubbing of the deed N/C unions was tested. The results are as follows , 1. In the two bath two step method, the staining of direct dye on nylon was decreased with the concentration of PMSBPS, and the fastness to washing, light, and rubbing of the dyed N/C unions were increased by addition of PMSBPS. 2. In the one bath two step method, optimun concentration of PMSBPS was 4% 0.w.f..

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Accurate Measurement of Twist Angle for Analysis of Azimuthal Anchoring Energy and Rubbing Direction of LC Panels of IPS Mode

  • Baek, S.H.;Rho, B.G.;Oh, J.M.;Dong, W.S.;Yang, B.K.;Kim, J.S.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.531-533
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    • 2007
  • A new method is developed for the measurement of twist angles of LC molecules in an LC panel with angular resolution of 0.01degree, which allows measurement of LC panels with small twist angles. The method is based on the analysis of the change in polarization state of a light beam as it passes through the LC panel in test is rotated in-plane. Compared to other traditional method, including the analysis of transmittance change, our method is more sensitive and more precise. This method allows accurate determination of anchoring energy and close analysis of the rubbing process in the fabrication of IPS mode LC panels.

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Neural network modeling of Pretilt Angle on the Homogeneous Polyimide Surface (신경망을 이용한 공정변수에 따른 수평 폴리머 표면의 경사각에 관한 연구)

  • Lee, Jung-Hwan;Ko, Young-Don;Kang, Hee-Jin;Seo, Dae-Shik;Yun, Il-Gu
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.426-427
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    • 2006
  • In this paper, the neural network model of the pretilt angle in the nematic liquid crystal on the homogeneous polyimide surface with different surface treatments is investigated. The pretilt angle is one of the main factors to determine the alignment of the liquid crystal display. The pretilt angle is measured to analyze the variation of the characteristics on the various process conditions. The rubbing strength and the hard baking temperature are considered as input factors. Latin hypercube sampling was used to generate initial weights and biases.

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How Do Liquid Crystal Molecules Align on Treated Surfaces?

  • Okada, Yoshinori;Shioda, Tatsutoshi;Chung, Doo-Han;Park, Byoung-Choo;Takezoe, Hideo
    • Journal of Information Display
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    • v.4 no.2
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    • pp.29-34
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    • 2003
  • We have studied liquid crystal (LC) molecular alignment on rubbed and photoaligned surfaces. Particular attention was paid to the intermolecular liquid crystalline interaction. We will first show that uniform molecular orientation on a rubbed surface does not mean spatially uniform interaction between the surface and LC molecules. Rather LCs tend to align themselves through LC interaction. The existence of nonuniformity of rubbing was successfully visualized by double surface treatment. The importance of intermolecular LC interaction was also found in the orientation formation process in 5CB evaporated on rubbed and photoaligned surfaces. By simultaneously analyzing polarized UVNIS absorption and second-harmonic generation (SHG) using the maximum entropy method, we succeeded in obtaining the temporal variation of the orientational distribution functions in the film forming process. The distribution anisotropy and pretilt are found to be generated under the influence of intermolecular LC interaction.

Patterning of liquid crystal alignment layers using selective dewetting process in a thermoplastic polymer film

  • Kim, Hak-Rin;Shin, Min-Soo;Lee, You-Jin;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1719-1722
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    • 2006
  • We proposed a soft-lithographic method for aligning a liquid crystal (LC) in patterned azimuthal orientations. It is demonstrated that a thermoplastic polystyrene layer is patterned from a thermally stable polyimide layer via pressure-assisted capillary force lithography, which provides multidirectional LC alignment condition simply followed by a unidirectional rubbing process.

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The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • v.17 no.12
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

Properties of liquid crystal alignment layers exposued to ion-beam irradiation enemies (이온빔 에너지에 따른 액정배향막의 전기광학적 특성연구)

  • Oh, Byeong-Yun;Lee, Kang-Min;Park, Hong-Gyu;Kim, Byoung-Yong;Kang, Dong-Hun;Han, Jin-Woo;Kim, Young-Hwan;Han, Jeong-Min;Lee, Sang-Keuk;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.430-430
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    • 2007
  • In general, polyimides (PIs) are used in liquid crystal displays (LCDs) as alignment layer of liquid crystals (LCs). Up to date, the rubbing alignment technique has been widely used to align liquid crystals on the PI surface, which is suitable for mass-production of LCDs because of its simple process and high productivity. However, this method has some disadvantages. Rubbed PI surfaces include the debris left by the cloth and the generation of electrostatic charges during rubbing process. Therefore, rubbing-free techniques for LC alignment are strongly required in LCD technology. In this experiment, PI was uniformly coated on indium-tin-oxide electrode substrates to form LC alignment layers using a spin-coating method and the PI layers were subsequently imidized at 433 K for 1 h. The thickness of the PI layer was set at 50 nm. The LC alignment layer surfaces were exposed to an $Ar^+$ ion-beam under various ion-beam energies. The antiparallel cells and twisted-nematic (TN) cells for the measurement of pretile angle and electro-optical characteristics were fabricated with the cell gap of 60 and $5\;{\mu}m$, respectively. The LC cells were filled with nematic LC (NLC, MJ001929, Merck) and were assembled. The NLC alignment capability on ion-beam-treated PI was observed using photomicroscope and the pretilt angle of the NLC was measured by the crystal-rotation method at room temperature. Voltage-transmittance (V-T) and response time characteristics of the ion-beam irradiated TN cell were measured by a LCD evaluation system.

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A Study on the Silk Degumming(1) - Degumming of Silk on Package - (견의 정련 방법에 관한 연구(1) - 패키지 정련 -)

  • Kim Moon-Sik;Kim Yong-Hak
    • Textile Coloration and Finishing
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    • v.18 no.3 s.88
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    • pp.16-22
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    • 2006
  • Process contract has received considerable attention in silk degumming processes because of its critical role in quality assurance. In degumming, process exhibits shrinkage of high twisted yarn and lot-varying behavior, thus increasing the difficulties of reduction by conventional means. This necessitates the application of a package that adapts to changing degumming process, and a new approach involving package degumming is proposed. The gains of this process are prevent of shrinkage by package winding, which is simplified by reduced soft-winding or re-twisting process. The approach is expected to achieve high quality results in conventional process due to its feature of demage by tension and rubbing. Therefore package degumming has many merits such as reduce of pilling and shrinkage, production expenses saving by process contract are expected of the simplified degumming process.