• Title/Summary/Keyword: cell alignment

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Zig-zag electrode pattern for improvement of electro-optic characteristic in polymer stabilized blue phase liquid crystal cell (고분자 안정화 블루상 액정셀의 전기광학특성 향상을 위한 지그재그 형태 전극 설계)

  • Kang, Wan-Seok;Mun, Byung-June;Lee, Gi-Dong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.1
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    • pp.183-187
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    • 2011
  • The polymer-stabilized blue phase liquid crystal (BPLC) cell has advantages such as sub-millisecond response time, wide viewing angle and no rubbing process for the alignment of liquid crystals. However, high operating voltage and low kerr constant of the polymer-stabilized blue phase liquid crystal deteriorate the electro-optical characteristic of the polymer-stabilized BPLC cell. In this paper, we proposed novel zig-zag electrode in cell layout and confirmed that proposed electrode shape could reduce an over 25 percent of operating voltage for BPLC cell without degradation of tranmittance by using Kerr constant simulation.

Generation of High Pretilt Angle in Liquid Crystal Cell with Slanted Non-Polarized Ultraviolet Light Irradiation on Polyimide Film as for Non-Rubbing Techniques (경사진 자외선을 폴리이미드막 표면에 조사한 넌러방법에 의한 액정소자의 고 프리틸트각의 발생)

  • Seo, Dae-Shik;Hwang, Lyul-Yeon;Lee, Bo-Ho
    • Proceedings of the KIEE Conference
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    • 1997.07d
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    • pp.1585-1587
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    • 1997
  • We investigated the generation of high pretilt angle for nematic liquid crystal (NLC) in the cell with slanted non-polarized ultraviolet (UV) light irradiation on two kinds of the polyimide (PI) film. It was shown that the monodomain alignment in NLC is obtained in the cell with slanted non-polarized UV light irradiation on PI surface. The pretilt angle of NLC is generated about 3 degrees in the cell with slanted non-polarized UV light irradiation with 70 degrees on PI surface without side chain. But, the pretilt angle of NLC is generated about 1 degree in the cell with slanted non-polarized UV light irradiation with 80 degrees on PI surface with side chain. We consider that the pretilt angle generation in NLC is attributted to anisotropic dispersion force between the LC molecular and the PI surface.

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Optimum configuration of a reflective LC cell with a diffractive nano-reflector

  • Park, Kyung-Ho;Lee, Gak-Seok;Kim, Jae-Chang;Yoon, Tae-Hoon;Kim, Jin-Hwan;Yu, Jae-Ho;Choi, Hwan-Young
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.614-615
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    • 2009
  • For the high reflectance under the ambient light condition, a highly efficient diffractive reflector has been proposed, based on a micro grating structure.[1] This reflector was designed to show highly concentrated distribution of the reflected light to the normal direction of the reflector under specific incident conditions of the light. In order to apply a diffractive reflector to a reflective liquid crystal display, the coupling between the viewing angle characteristics of a liquid crystal (LC) cell and the reflective distribution of the reflector should be considered. Under the optimum configuration confirmed through the analysis of the coupling between a LC cell and a reflector, a reflective vertical alignment (VA) cell with a diffractive reflector shows contrast ratio and brightness much higher than that with a conventional bumpy reflector.

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A Fast Response Smectic LCD using Induced Polarization

  • Mochizuki, Akihiro
    • Journal of Information Display
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    • v.6 no.3
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    • pp.6-11
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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 sa me with current nematic base LCDs. Specific initial molecular alignment as well as specific cell design realizes ext remely 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 herein.

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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Measurement of anchoring strength of a photo-polymer for LC alignment

  • Hahn, Soon-Koo;Kang, Dae-Seung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.619-621
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    • 2003
  • We have presented in the paper preliminary results on physical characteristic parameters of a photopolymer LPPF 301 CP. The weak azimuthal anchoring energy (${\sim}5.0{\times}10^{-6}J/m^2$) of a photopolymer was measured by using a simple optical method. High pretilt up to $30^{\circ}$ has been achieved in the photoaligned cell by irradiating an obliquely incident UV light.

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High Resolution Analysis for Defective Pixels Detection using a Low Resolution Camera

  • Gibour, Veronique;Leroux, Thierry;Bloyet, Daniel
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.856-859
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    • 2002
  • A system for high-resolution analysis of defective elementary cell (R, G or B) on Flat Panel Display (FPD) is described. Based on multiple acquisitions of low-resolution shifted images of the display, our system doesn't require a high-resolution sensor neither tedious alignment of the display, and will remain up to date even facing an important increase of the display dimensions. Our process, highly automated and thus flexible and robust, is expected to perform a full analysis in less than 60s. It is mainly intended for production tests and display classification by manufacturers.

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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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Shearing and Electro-optical Properties of Stressed Cholesteric Liquid Crystal Cells

  • Lee, Jung-Min;Kang, Dae-Seung
    • Journal of Information Display
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    • v.11 no.2
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    • pp.91-93
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    • 2010
  • The shearing effects on the electro-optical properties of a stressed cholesteric liquid crystal were investigated. A photopolymer was dispersed in the cholesteric liquid crystal cell. By carefully choosing the mixing ratio between the liquid crystal and the photoreactive monomer, and by applying suitable mechanical shearing on the substrates, a cholesteric liquid crystal display with a low threshold voltage and no alignment layer was demonstrated.

Interference Space Reuse and the Adoption Strategy through QoS Constraints in Three-Cell Downlink MIMO Interference Channels (3-Cell 하향링크 MIMO 간섭 채널에서의 간섭 공간 재활용 및 QoS Constraint에 따른 그 적용 방안)

  • Yoon, Jangho;Lee, Hwang Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37A no.12
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    • pp.1093-1105
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    • 2012
  • We propose an interference space reuse (ISR) algorithm for the MU-MIMO design in 3-cell downlink interference channels. Also, we provide a strategy for the adoption of the ISR scheme in the cellular network. In the multicell interference channels, the cell edge users may undergo severe interferences and their signals should be protected from the interferers for reliable transmissions. However, the intra cell users do not only experience small interferences but also they require small transmission power for stable communication. We provide a vector design algorithm based on ISR, where intra cell users are served through reusing the cell edge users' interference space. The performance enhancement reaches 20% compared to the fractional frequency reuse (FFR) scheme combined with IA through the scheduling between the cell edge users and the intra cell users. Also, it can be used to enhance the cell edge throughput when the quality of service (QoS) requirements of the intra cell users are fixed.