• Title/Summary/Keyword: crystal alignment

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Liquid Crystal Alignment on Treated Surfaces

  • Chung, Doo-Han;Shioda, Tatsutoshi;Okada, Yoshinori;Park, Byoung-Choo;Takezoe, Hideo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1088-1091
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    • 2003
  • We have studied liquid crystal orientation on rubbed and photoaligned polymer surfaces. The following topics will be presented; (1) visualization of nonuniformity of rubbing, (2) competition between grooves and photoalignment and (3) alignment process of 5CB evaporated on treated surfaces. Through these topics, the importance of the intermolecular liquid crystalline interaction will be emphasized.

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Soft-lithography for preparing patterned liquid crystal orientations

  • Kim, Hak-Rin;Jung, Jong-Wook;Shin, Min-Soo;Kim, Myung-Eun;Lee, You-Jin;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.615-620
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    • 2006
  • We demonstrate novel soft-lithographic techniques for preparing patterned liquid crystal (LC) orientations at an alignment layer. By controlling patterning conditions such as wetting property and operating temperature depending on polymeric materials, multi-directional or modified LC alignment conditions can be simply achieved.

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Properties of Photo-regulation of Liquid Crystal Alignment and Generation of Maxwell-displacement-current for Application with a Medical Engineering Device (의료용 초박막 액정의 광배향 제어와 광변위 전류 특성)

  • Lee, Ho-Shik;Ahn, Joon-Ho;Kim, Woo-Yeon;Iwamoto, M.;Lee, Won-Jae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.12
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    • pp.1160-1166
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    • 2006
  • Maxwell-displacement-current (MDC) measuring technique has been applied for the investigation of monolayers of poly(vinyl alcohol)s bearing azobenzene side-chains (6Az5PVA) mixed with p-pentyl-p'-cyano-biphenyls (5CBs) on a water surface. For mixed monolayers containing trans-form 6Az5PVA and LCs, displacement current due to photo isomerization was not generated with alternative photo-irradiation with UV and svisible light. In contrast, for mixed monolaters containing cis-form 6Az5PVA and LCs, displacement current was generated. Finally, it was found that the alignment layers deposited in cis-form could photoregualte the orientation of LCs.

Electro-Optical Characteristics of Plastic STN Cell using Low Temperature Process (저온 공정을 이용한 플라스틱 STN 셀의 전기 광학 특성)

  • Kim, Kang-Woo;Hwang, Jeoung-Yeon;Kim, Jong-Hwan;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05a
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    • pp.202-205
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    • 2004
  • We investigated the electro-optical(EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface using polymer film. The NLC pretilt angles generated are about $18^{\circ}$ by the rubbing alignment method on thin plastic substrates. However, the pretilt angle are at about $13^{\circ}$ lower on the glass substrate than on thin plastic substrate. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance(V-T) curve of the plastic STN-LCD was observed on the polyimide(PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide(PI) surfaces using polymer film can be achieved.

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Electro-optical Characteristics of a Multi-domain Vertical-alignment Liquid Crystal Display on Homeotropic Photopolymer Layer

  • Hwang, Jeoung-Yeon;Lee, Kyung-Jun;Seo, Dae-Shik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.511-513
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    • 2002
  • Electro-optical characteristics of new multi-domain vertical-alignment (MVA) liquid crystal displays (LCDs) with negative dielectric anisotropy on a homeotropic photopolymer were studied. Good voltage-transmittance (V-T) curves by the new MVA-LCD on the homeotropic photo-polymer were obtained. Also, the stable response time of MVA-LCD on the homeotropic photopolymer can be achieved. The viewing angle of the new MVA-LCD could be improved by the grating groove with UV exposure and development on the photo-polymer.

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Multidirectional Liquid Crystal Orientation by Using Ion Beam Irradiation

  • Ahn, Han-Jin;Kim, Kyung-Chan;Kim, Jong-Bok;Hwang, Byung-Har;Baik, Hong-Koo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.543-546
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    • 2005
  • We have investigated the alignment ability of multi-domains by using ion beam irradiation on diamond-like carbon (DLC) thin film layers. The DLC thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) system and the low energy ion beam is irradiated from Kaufman type ion gun. The direction of liquid crystal alignment is varied by the direction of Ar ion beam irradiation.

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A Study on wide viewing angle and fast response time using new VA-$\pi$ cell mode (새로운 VA-$\pi$ 셀 모드를 이용한 광시야각과 고속 응답에 관한 연구)

  • 서대식;이정호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.332-336
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    • 2000
  • We have developed a novel vertical-alignment(VA) -$\pi$ cell mode that provides a wide viewing angle and fast response times for nematic liquid crystal(NLC) with negative dielectric anisotropy on a homeotropic polymide(PI) surfaces. Good voltage-transmittance curves and low driving voltages were achieved with the new VA-$\pi$ cell mode without a negative compensation film. Iso-viewing angle characteristics using the new VA-$\pi$ cell mode without a negative compensation film was also successfully observed. As well a fast response time of 31.7 ms for a new VA-$\pi$ mode was measured. Consequently the iso-viewing angel fast response time and low driving voltage characteristics using a VA-$\pi$ cell can be achieved.

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Pattern Check According To The Rubbing Direction Of The LC VA Cell (VA 액정 셀의 러빙방향에 따른 패턴 확인)

  • Kim, Jeong-ha;Kim, Hak-rae;Song, Jang-kun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.481-483
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    • 2015
  • In order to understand the characteristics of the LCD, we make Vertical Alignment Liquid Crystal Cell and check the pattern that appears in Cell flowing a current. After giving different rubbing directions on made cell, check and compare various patterns appeared on the cell, research the cause of the patterns. When we apply a current to the cell, lines appear on the cell. We find that higher voltage and frequency make many lines on the cell.

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Enhancement of electro-optic performance in dyesensitized solar sell using homeotropically aligned liquid crystal molecular

  • Kim, Hyeon-Kyung;Jin, Sung-Ho;Lee, Gi-Dong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1130-1132
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    • 2009
  • We propose a novel way for enhancement of efficiency on a quasi solid-state dye-sensitized solar cell (DSSC). It contained gel type electrolyte mixing the liquid crystal (LC) of specific concentration and applied voltage for alignment of the LC. Aligned LC is supported charge transfer inside electrolyte and efficiency is increased in DSSC. We made a quasi solid-state DSSC which applied DC voltage or not and have measured the power conversion efficiency (PCE) and the fill factor. From measurement, we obtain high performances in case of cell applied voltage compare to reference cell.

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New Liquid Crystal Photoalignment Materials Based on Photosensitive Polyimides Having Long Alkoxy Cinnamate Chains

  • Wu, Jing-Jing;Jeong, Seok-Jin;Lee, Seung-Hee;Lee, Myong-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.893-896
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    • 2007
  • A series of new photosensitive polyimides having long alkoxy cinnamate chains were synthesized for liquid crystal (LC) photoalignment material. The polymer after irradiating linearly polarized UV light induced homogeneous and stable LC alignment. The chemical structure of the polymeric material was characterized and their photochemical LC alignment behavior was evaluated.

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