• Title/Summary/Keyword: liquid crystal devices

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Abnormal Behavior in Color Tracking in the Fringe-Field Switching (FFS) Liquid Crystal Display

  • Jung, Jun-Ho;Ha, Kyung-Su;Chae, Mi-Na;Cho, In-Young;Kim, Woo-Il;Kim, Dae-Hyun;Kim, Sung-Min;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.616-619
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    • 2009
  • Color tracking behavior of in the fringe-field switching (FFS) mode using a liquid crystal with positive dielectric anisotropy has been studied. In the in-plane switching and vertical alignment devices, color chromaticity at normal direction changes from bluish to yellowish white linearly with increasing grey levels from dark to white state. Interestingly, abnormal behavior in color tracking is observed in FFS devices using a liquid crystal with positive dielectric anisotropy, that is, it changes from bluish to yellowish up to a certain middle grey level but turns over to bluish white with further increasing from a grey level to a fully white state. In this paper, we analyze this abnormal effect from the calculated and experimental results.

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Flexible Ferroelectric Liquid Crystal Display Devices Using Thin Plastic Substrates Fastened by Polymer Walls and Networks

  • Sato, Hiroto;Fujikake, Hideo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.305-308
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    • 2003
  • We fabricated a flexible ferroelectric liquid crystal (FLC) device containing polymer walls and networks which fix plastic film substrates. The device using 100-${\mu}m$-thick substrates could be bent in a radius of 7mm without disordering the FLC alignment. When sandwiched between polarizers a roll-up display with high-speed grayscale capability for moving-image displays was created.

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Electro-optical characteristics of liquid crystal alignment layer modified by ion beam irradiation (액정배향막 표면 개질에 따른 전기광학적 특성연구)

  • Oh, Byeong-Yun;Seo, Dae-Shik
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.513-514
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    • 2008
  • The potential of non-rubbing technology for applying to display devices was demonstrated by irradiating a high density argon ion beam (IB) on a polyimide (PI) as a liquid crystal alignment layer. The superior electro-optical characteristics were obtained, compared to rubbed PI, Although the low pretilt angle was created on the IB irradiated PI.

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Carbon nanotube based transparent electrodes for flexible displays using liquid crystal devices

  • Shin, Jun-Ho;Lee, H.C.;Lee, J.H.;Park, S.M.;Alegaonkar, P.S.;Yoo, J.B.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.897-899
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    • 2007
  • Transparent electrodes for a flexible display based on the liquid crystal (LC) were formed by carbon nanotubes (CNTs) on polyethylene terephthalate (PET) substrates. The thin multi wall carbon nanotubes (t-MWNTs) networks for electrodes were obtained by filtration- transfer method from welldispersed CNTs solution.

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Low-dislocation-density large-diameter GaAs single crystal grown by vertical Bridgman method

  • Kawase, Tomohiro;Tatsumi, Masami;Fujita, Keiichiro
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.6
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    • pp.535-541
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    • 1999
  • Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

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Pixel isolated liquid crystal mode for flexible displays

  • Lee, Hyun-Gi;Jung, Jong-Wook;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.615-618
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    • 2003
  • We developed a new device structure using anisotropic phase sepraration from liquid crystals (LCs) and polymer composite materials for flexible display applications. In the device, the LC molecules are isolated in pixels where LCs are surrounded by polymer layers. These devices show very good mechanical stability against external pressure. The electro-optic characteristics and the mechanical stability of the devices are discussed in view of the flexible display applications.

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Crystal Growth of LiNbO3 for SAW Devices (SAW Device 응용을 위한 LiNbO3 단결정 성장)

  • 최종건;오근호
    • Journal of the Korean Ceramic Society
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    • v.25 no.1
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    • pp.78-82
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    • 1988
  • Good quality LiNbO3 single crystals which can be applied to SAW devices, were grown by Czochralski method. It was observed that the gas-bubbles were concentrated in ring shape at the outer part of grown crystals, and this anomaly was illustrated by modeling the mechanism of gas-bubble entrapment according to the melt flow pattern in the crucible. And this mechanism was also encertained by observation of solid-liquid interface shape of grown crystals. The optimal condition for good quality crystals was known that the solid-liquid interface shape was slightly concave.

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The Effect of Layer Spacing Changes in the SmA Phase on Defects Observed in SSFLC Devices.

  • Wang, Chenhui;Bos, Philip J.;Kumar, Satyendra;Wand, Michael;Handschy, Mark
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.193-197
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    • 2004
  • The effect of the temperature dependence of the smectic layer spacing in the smectic-A (SmA) phase on the formation of defects in the ferroelectric smectic-$C^{\ast}$ ($SmC^{\ast}$) phase is investigated with x-ray scattering technique. The study is based on thin parallel-aligned surface stabilized ferroelectric liquid crystal cells with two different alignment conditions, high pretilt $SiO_x$, alignment and low pretilt polyimide films. It is found that defects observed in the $SmC^{\ast}$ phase have much more profound dependence on the layer changes and chevron formation in the SmA phase than in the $SmC^{\ast}$ phase. We find that thermal layer expansion with decreasing temperature in the SmA phase suppresses the formation of defects observed in the SmC phase.

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Micro-Contact Printing Method for Patterning Liquid Crystal Alignment Layers

  • Jung, Jong-Wook;Kim, Hak-Rim;Lee, You-Jin;Kim, Jae-Hoon
    • Journal of Information Display
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    • v.7 no.2
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    • pp.12-15
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    • 2006
  • We propose a patterning method of liquid crystal (LC) alignment layer for producing multi-domain LC structures. By controlling thermal conditions during micro-contact printing procedures and facilitating wetting properties of patterning materials, patterned LC orientation can be easily obtained on a bare ITO surface or other polymer films. The newly proposed patterning method is expected to be a very useful tool for fabricating multi-domain LC structures to enhance or design electro-optic properties of LC-based devices.

Integration of solution-processed polymer thin-film transistors for reflective liquid crystal applications

  • Kim, Sung-Jin;Kim, Min-Hoi;Suh, Min-Chul;Mo, Yeon-Gon;Chang, Seung-Wook;Lee, Sin-Doo
    • Journal of Information Display
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    • v.12 no.4
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    • pp.205-208
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    • 2011
  • Herein, the integration of solution-processed polymer thin-film transistors (TFTs) that were fabricated using selective wettability through ultraviolet (UV) exposure into a reflective liquid crystal display is demonstrated. From the experimental results of energy-dispersive spectroscopy, the composition of carbon and fluorine enhancing the hydrophobicity in the polymer chains was found to play a critical role in the wetting selectivity upon UV exposure. The polymer TFTs fabricated through the wettability-patterning process exhibited long-term stability and reliability. This wetting-selectivity-based patterning technique will be useful for constructing different types of solution-processed electronic and optoelectronic devices.