• Title/Summary/Keyword: Nematic liquid crystal

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Dielectric Relaxation in Electrooptical Switching of Nematics

  • Lavrentovich, Oleg D.;Wonderly, Hugh;Gu, Mingxia;Shiyanovskii, Sergei V.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1283-1285
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    • 2008
  • We describe how the phenomenon of dielectric dispersion in nematic liquid crystals influences the director dynamics and thus the switching speed of nematic-based displays.

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The Study of Transmission Spectrum of Twisted Nematic Liquid Crystal Doped with Phosphorus Micro Particles Apply for Vehicle Lamp

  • Minh-Tran, Anh
    • International Journal of Internet, Broadcasting and Communication
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    • v.15 no.1
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    • pp.145-149
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    • 2023
  • In this study, the spectrum changes induced from the doping of phosphor micro particles in a twist nematic liquid crystal cell was observed. The experimental results show that the achromatic transmission can be observed with a proper driving condition, which may be applied to the design of an achromatic liquid crystal device. In this paper, we tried to figure out the spectrum changes induced from the doping of phosphor micro particles. The experimental result of the phosphor powder doped twist nematic liquid crystal cell shows that the achromatic transmission and the wavelength linearly dependent transmission both can be observed with some proper driving conditions, respectively. The result is useful on developing an achromatic liquid crystal device and it can be applied for Vihicle lamp.

Vertical Alignment of Nematic Liquid Crystal on the SiC Thin Film Layer with Ion-beam Irradiation

  • Oh, Yong-Cheul;Lee, Dong-Gyu
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.6
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    • pp.301-304
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    • 2006
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of the SiC (Silicon Carbide) thin film. The SiC thin film exhibits good chemical and thermal stability. The good thermal and chemical stability make SiC an attractive candidate for electronic applications. A vertical alignment of nematic liquid crystal by atomic beam exposure on the SiC thin film surface was achieved. The about $87^{\circ}$ of stable pretilt angle was achieved at the range from $30^{\circ}\;to\;45^{\circ}$ of incident angle. Consequently, the vertical alignment effect of liquid crystal electro-optical characteristic by the atomic beam alignment method on the SiC thin film layer can be achieved.

Molecular Orientation and Optical Properties of Liquid Crystal Mixture Films of Photo-Reactive Mesogens and Non-Reactive Nematic Liquid Crystals (광경화성 액정과 비반응성 네마틱 액정 혼합 필름의 분자 배향 및 광학 특성)

  • Lee, Mong-Ryong;Shin, Mi-Young;Kim, Sung-Hyun;Song, Ki-Gook
    • Polymer(Korea)
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    • v.35 no.5
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    • pp.493-498
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    • 2011
  • Reactive mesogens were used to prepare photo-cured liquid crystal films in which orientations of liquid crystal molecules were preserved by crosslinked networks of cured reactive mesogens. The molecular orientations of liquid crystal mixtures of photo-reative mesogens and non-reactive nematic liquid crystals were studied and compared before and after curing reactions. The effects of temperature and the amount of the non-reactive nematic liquid crystal in the mixture on birefringence of the liquid crystal films were investigated. It was found that optical compensation films with different birefringence could be prepared by controlling the amount of the nematic liquid crystals in the reactive mesogen mixtures.

Surface Driven Switching in Liquid Crystal Displays

  • Komitov, Lachezar
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.14-16
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    • 2009
  • Surface driven switching of the liquid crystal bulk arising from the coupling between an applied electric field and a polarized state of a nematic liquid crystal, both localized at the substrate surface, is reported. Fast switching is demonstrated in a hybrid aligned nematic cell with a fringe electric field generated by comb-like electrode structure.

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Liquid crystal alignment on the inkjet printed polyimide by using new alignment method

  • Hwang, J.Y.;Wonderly, H.;Chien, L.C.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.506-508
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    • 2007
  • We studied the nematic liquid crystal (NLC) alignment capability with a new alignment method utilizing an inkjet printed polyimide (PI) layer. A good, uniform LC alignment was achieved by the good PI printing using a new alignment method. The pretilt angle generated on the printed PI layer using the alignment method was almost the same as that on printed PI layer using rubbing alignment method. In addition, the good electro-optical performances of the new aligned twisted nematic (TN) cell with printed PI surface was obtained

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Electro-Optical and Switching Behavior of In-plane Switching Twisted Nematic Liquid Crystal Display

  • Kimura, Munehiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1092-1095
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    • 2003
  • A driving mechanism and excellent features for an in-plane switching twisted nematic liquid crystal mode (IT mode) that could possibly improve the viewing-angle and color shift characteristics and the cell gap error tolerance is proposed. .It is important that the surface azimuthal anchoring strength of the liquid crystal cell differs at the upper and lower substrates. Furthermore. as a rubbing-free LCD. amorphously aligned in-plane switching twisted nematic mode (a-IT mode) is also demonstrated.

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Fast Switching Polymer-Stabilized Bend Nematic Devices

  • Kim, Sang-Hwa;Chien, Liang-Chy
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.194-195
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    • 2002
  • We report a fast-switching polymer-stabilized bend nematic (PSBN) device. The morphology study reveal a templated polymer networks captures the orientation of the field deformed nematic host.

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Optical Simulation of Viewing Angle Property of Biaxial Nematic Bent-Core Liquid Crystal

  • Yang, Seungbin;Lee, Ji-Hoon
    • Journal of the Optical Society of Korea
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    • v.20 no.4
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    • pp.510-514
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    • 2016
  • The conventional liquid crystal displays (LCDs) have been using optically uniaxial liquid crystal (LC) medium and this often causes a significant image change at oblique viewing angles. We simulated the viewing angle properties of the biaxial nematic (Nb) phase of a bent-core liquid crystal (BLC) and compared the results with the vertically aligned (VA)- and the in-plane switching (IPS)-LCDs. The Nb phase of the BLC showed a smaller transmittance at the dark state as well as a greater contrast ratio at wide viewing angle. The viewing angle property of the Nb-mode without any compensation film was slightly superior to the IPS-mode with the compensation films eliminating the decross of the polarizers at oblique viewing angle.

Study on Pressure-dependent Dynamics of Liquid Crystal in a Twisted Nematic Liquid Crystal Cell with Thin Film Transistor (TFT를 이용한 비틀린 네마틱 액정 셀에서 외부 압력에 따른 액정 동력학에 관한 연구)

  • 고재완;김미숙;정연학;김향율;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.4
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    • pp.426-431
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    • 2004
  • We have studied the pressure-dependent liquid crystal's dynamics in a twisted nematic (TN) liquid crystal panel with thin film transistor by applying an external pressure to it. When the external pressure is applied to the panel in a dark state, the disclination lines were generated as a light leakage whereas they did not appear in a simple test cell that has only pixel and common electrodes. It was because the disclination lines were Provoked by the electric field between pixel electrode and data/gate bus line for active matrix driving. Consequently, the external pressure resulted in dynamic instability of the liquid crystal so that the disclination lines at the data/gate bus line intruded into the active area.