• Title/Summary/Keyword: Liquid Crystal Alignment

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3-D FEM Study on the Optical Characteristics of S-IPS Mode

  • Yang, Seung-Su;Park, Soon-Yeol;Won, Tea-Young
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.231-234
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    • 2008
  • In this paper, we propose a novel electrode structure for superb transmittance in super in-plane switching (S-IPS) mode while keeping the features of the conventional SIPS mode such as the capability of initial LC alignment. The optimization of the electrode made it possible to enhance the light transmittance approximately by 14 % in comparison to the conventional S-IPS cell.

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A General Performance of PSS-LCDs

  • Mochizuki, Akihiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.91-96
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    • 2005
  • In this paper, a general performance of the PSS-LCD or Polarization Shielded Smectic Liquid Crystal Display is discussed. This smectic base LCD does not use any spontaneous polarization, but uses induced polarization just same with current nematic base LCDs. Specific initial molecular alignment as well as specific cell design realizes extremely fast optical response speed with native wide viewing angle. Moreover, this performance is provided by full compatible electronics for current conventional LCDs. A general performance of the PSS-LCD is introduced here.

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A New Electrode Structure for Color-shift Reduction in PVA LCD

  • Kwon, Yong-Hoan;Baek, Jong-In;Kim, Jae-Chang;Yoon, Tae-Hoon
    • Journal of Information Display
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    • v.8 no.3
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    • pp.17-21
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    • 2007
  • We introduce a new electrode structure for the patterned vertical alignment (PVA) mode, which has a lower color-shift at large viewing angle than the one-domain VA mode. By manipulating the period of electrode structure, we can make more multi-domains and use the existing fabrication processes without having to use additional materials.

Synthesis of Poly(cinnam-4'-yl methyl methacrylate) Derivatives and Their Thermal Stability as Photoalignment Layer

  • Lee, Jong U;Kim, Hak Won;Kim, Hong Du
    • Bulletin of the Korean Chemical Society
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    • v.22 no.2
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    • pp.179-182
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    • 2001
  • Photocyclizable poly(cinnam-4'-yl methyl methacrylate) derivatives bearing methoxy benzene (PMCMMA), anthracene (PACMMA), and coumarin (PCCMMA) have been synthesized via Heck type reaction. Three different types of polymers are photoreactable usin g linearly polarized UV light and applicable as liquid crystal alignment layer. Anthracence and coumarin containing polymers (PACMMA, PCCMMA) have better thermal stability than PMCMMA. This observation may be attributed to the glass transition temperature elevation due to the bulky size and another photocrosslinking site provided by anthracene or coumarin group.

Azimuthal anchoring measurement of nematic liquid crystals using the strong magnetic field

  • Jang, Tae-Sug;Im, Ji-Young;Goh, Wan-Hee;Kim, Jong-Hyun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.664-667
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    • 2009
  • We would like to show a measuring technique of azimuthal anchoring energy of the nematic liquid crystals. The electro-optical setup of liquid crystal cell, crossed polarizers and magnetic field was assumed. The planar or hybrid alignment cells were prepared. The director in the light entering substrate and the polarization of light was adjusted into parallel to the magnetic field. The director orientation of exit substrate and analyser maintained perpendicular to the magnetic field. As the magnetic field strength is increased, the director deviates from the easy axis and rotates to the field direction. We obtained an equation calculating the change of transmission with the field and measured experimentally the transmission. By comparing the calculating and experimental data, we obtained the azimuthal anchoring strength.

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Electro-optical Properties of Polymer Dispersed Liquid Crysta Displays (고분자 분상형 액정표시소자의 전기광학적 특성 연구)

  • 박우상;고영부;박세근
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.10
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    • pp.885-890
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    • 1998
  • The electro-optical properties of polymer dispersed liquid crystals (PDLCs) depend on dispersion structures and nematic alignment which can be controlled by taking proper liquid crystal/polymer mixtures and process conditions. To achieve excellent electro-optical properties such as low driving voltage, good contrast ratio and negligible hysteresis, we have developed optimization procedure. Under the optimized conditions, PDLC of low threshold voltage less than 3.1 V, high contrast ratio more than 150 and negligible hysteresis were obtained.

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A Study on Electro-optical Characteristics of the UV Aligned FFS Cell on the Organic Layer

  • Han, Jeong-Min;Ok, Chul-Ho;Hwang, Jeoung-Yeon;Kim, Byoung-Yong;Kang, Dong-Hun;Kim, Jong-Hwan;Kim, Young-Hwan;Han, Jin-Woo;Lee, Sang-Keuk;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.8 no.3
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    • pp.135-138
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    • 2007
  • In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide: PI). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photoalignment method were studied; Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via insitu photo alignment method for 2 h and 3 h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method (1 h), and V-T curve of UV-aligned FFS-LCD with in-situ photo alignment method was much stable comparing with that of other UV-aligned FFSLCD's. As a result, more stable EO performance of UV-aligned FFS-LCD with in-situ photoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

A New Method for Measuring Azimuthal Anchoring Energy of Rubbed and UV-Exposed Polyimide Alignment Layers

  • Park, H.J.;Lee, W.K.;Kim, D.G.;Shin, D.C.;Woo, J.W.;Shin, H.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1619-1621
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    • 2007
  • Novel optical measurement systems and improved cell configurations for measuring of azimuthal anchoring energies were developed. The difference between the mechanical rubbing direction and the optical easy axis that caused errors in the previous azimuthal anchoring energy measurement was compensated. In addition, the measurement accuracy of the twist angle and therefore the azimuthal anchoring energy was greatly enhanced. As a result, we were able to obtain valid azimuthal anchoring energy values for different alignment layers.

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A Study on Electro-optical Characteristics of the Photoaligned VA-LCD on the Polynobornene Derivative Surface (Polynobornene 유도체 표면을 이용한 광배향 VA-LCD의 전기광학특성에 관한 연구)

  • 황정연;서대식;박경선;서동학;남상희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.3
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    • pp.253-257
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    • 2002
  • A new photoalignment material PNC, pole norbornene-2,3-dicarboxyolyl cholesterol, was synthesized and the electro-optical (EO) characteristics of the vortical-alignment (VA) liquid crystal display (LCD) photoaligned with UV exposure on the PNC surface were studied. EO characteristics of the photoaligned VA-LCD using a UV filter-less method was better than that of the UV filter method on the PNC surface for short UV exposure time. The response time of the photoaligned VA-LCD on the PNC surface without UV filter on the PNC surface is almost the same compared with the rubbing aligned VA-LCD.