• Title/Summary/Keyword: Liquid Crystal Display

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Development of Fast Response Time (16msec) in IPS Mode

  • Lim, C.S.;Lee, J.H.;Oh, C.H.;Choi, H.C.;Lee, Seung-Eun;Jin, Min-Ok;Klasen-Memmer, M.;Tarumi, K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.68-71
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    • 2003
  • To be able to show moving images without visual problems like blurring and tailing, the response time of liquid crystal display (LCDs) must be improved. In this paper we will discuss our progress in improving the response time by optimizing the cell configuration and the use of new liquid crystal mixtures. A 20.1inch diagonal UXGA IPS TFT-LCD has been developed having a response time as fast as l-frame time (16msec) for white-black operation and less than 16msec in all gray levels without applying ODC (Over Driving Circuit). This is very important because one of the technology to reduce motion blurring, the use of scanning backlight is conditioned by 16msec for all grays. The excellent gray-to-gray response can be explained by virtue of fundamental characteristics of S-IPS mode and makes a good contrast with the results of VA mode.

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이온빔 조사를 사용한 탄탈륨 산화막에서의 액정 배향에 대한 조사 (Research of Liquid Crystal Alignment on Tantalum Oxide by Using Ion Beam Irradiation)

  • 임지훈;오병윤;이원규;이강민;나현재;박홍규;서대식
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.300-300
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    • 2008
  • In this study, the advanced DuoPIGatron-type ion beam (IB) system was applied to inorganic thin film for aligning liquid crystal (LC). LC alignment on $Ta_2O_5$ via IB irradiation was embodied. As a result of IB irradiation, the homogeneously aligned liquid crystal display (LCD) on $Ta_2O_5$ was observed with low pretilt angles. The $Ta_2O_5$ were deposited on indium-tin-oxide coated Coming 1737 glass substrates by rf magnetron sputtering at $200^{\circ}C$. The deposition process resulted in forming very uniform thin film on glass substrates without any defects. To confirm the application of the inorganic alignment on modem display optical devices, we fabricated twisted nematic LCD and measured optical property and response time. As a result of the experiment, the electro optical characteristics of the LCD fabricated by using IB irradiation on $Ta_2O_5$ alignment layer were similar with the other LCD fabricated by using rubbing process.

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Advanced Liquid Crystal Materials for Fast Switching Times

  • Jin, Min-Ok;Yoon, Dong-Kyu;Kim, Eun-Young;Lee, Seung-Eun;Heckmeier, M.;Klasen-Memmer, M.;Sem, G L;Tarumi, K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1118-1120
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    • 2003
  • For LCD-TVs with full capability to show moving pictures and LCD monitors for multi media use, it is necessary that the switching times of Liquid Crystal (LC) mixtures are within one frame (16.7ms). In order to achieve faster switching times, new LC materials have been identified, mainly focusing on the further reduction of the rotational viscosity (${\gamma}1$).

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Dark-state Color Shift and Gray Scale Inversion in an In-plane Switching Liquid Crystal Display Device

  • Park, Sung Il;Park, Kyoung-Ho;Lee, Joun-Ho;Yoon, Jeong Hwan;Kim, Byeong Koo;Yu, Byeong-Hun;Kim, Ki-Han;Yoon, Tae-Hoon
    • Journal of the Optical Society of Korea
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    • 제16권4호
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    • pp.409-413
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    • 2012
  • Off-axis color shift in the dark state and gray scale inversion in an in-plane switching (IPS) liquid crystal display (LCD) device were investigated. Analyses were performed using the Poincar$\acute{e}$ sphere representation. The results show that color shift in the dark state and gray scale inversion in an IPS LCD can be reduced by using a biaxial film. We confirmed the extent of these improvements by measuring the optical performance of a fabricated IPS LCD.

Formation of 3-Dimensional Networks of Colloidal Particles in a Nematic Host

  • West, John L.;Glushchenko, Anatoliy;Zhang, Ke;Reznikov, Yuri
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.191-192
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    • 2002
  • We reported pushing of colloidal particles by a moving isotropic-nematic phase boundary. Here, we report tailoring the structure of 3-dimensional networks formed by these particles by adjusting the rate of phase transition and by application of an electric field. The resulting networks affect the electro-optic performance of liquid crystal devices.

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Coherent director rotation and memory effects, and their dependence on the morphology of the constituent molecules in thiol-ene polymer stabilized ferroelectric liquid crystal system

  • Lim, Tong-Kun;Lee, Ji-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.199-202
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    • 2005
  • We have studied the origin of coherent director rotation [CDR] as well as memory behavior in thiol-ene polymer stabilized ferroelectric liquid crystal [FLC]. The ene constituents are found to be always located at the inter-layer space and induce the coherent director rotation motion of liquid crystal molecule. On the other hand, the thiols are more intersticed between ferroelectric liquid crystal molecules at intra-layer as the thiol gets longer, and these intersticed thiols enhance the multistability and the resolution of memory state of FLCs.

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Dual Frequency Switchable Flexoelectric Cholesteric Devices

  • Chien, Liang-Chy;Shi, Lei
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.105-108
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    • 2005
  • We demonstrate an electro-optical device based on the flexoelectric effect of a short-pitched cholesteric liquid crystal. By using a dual-frequency switchable nematic, a small amount of chiral dopant and a small amount of phase-separated polymer localized on the surface, we were able to create a device that operates in amplitude (flexoelectric) and phase(dielectric) modes. At high frequency the dual frequency liquid crystal suppresses the phase mode at higher voltage, which improves the switching speed, and thereby preserving the in-plane-switching mode.

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Polarizer-free Liquid Crystal Devices

  • Lin, Yi-Hsin;Ren, Hongwen;Wu, Yung-Hsun;Wu, Shin-Tson
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.980-981
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    • 2007
  • Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. They usually require two polarizers; therefore the optical efficiency is limited. We introduce two general principles of polarization-free liquid crystal devices and also show several LC devices by applying the principles.

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Eelectro-optic Behavior of Opal-LC Photonic Crystals

  • Kang, Dae-Seung
    • Journal of Information Display
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    • 제2권4호
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    • pp.19-22
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    • 2001
  • In this paper, we describe the electro-optic effects of photonic crystals made of a synthetic opal filled with a nematic liquid crystal(LC). By applying an external electric field, a shift in the Bragg reflection peak position(stop band) and a field-induced change in its peak reflectivity are observed. These significant surface alignment effects of the opal-LC composite are discussed in a similar manner for Freederick-type transitions of LC within a confined geometry in the presence of external fields.

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수평 배향된 네마틱 액정 디스플레이에서 액정의 광축과 편광판축의 편향각에 따른 명암 대비비 값 비교 (Comparison of Contrast Ratio in a Homogeneously Aligned Nematic Liquid Crystal Display Depending on an Angle Between Polarizer Axis and Optic Axis of a Liquid Crystal)

  • 송일섭;원해경;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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    • pp.150-152
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    • 2004
  • We have studied contrast ratio of a homogeneously aligned nematic liquid crystal (LC) display as a function of the angle between the polarizer axis and LC director. The results show that a cell configuration in which a polarizer axis facing a light source coincides with a short LC axis has a better process margin in terms of high contrast ratio than that of the cell coinciding with a long LC axis.

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