• Title/Summary/Keyword: LC material

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Controllable Pretilt Angles for Liquid Crystal Molecules using a Rubbing Treated Mixture Layer

  • Kim, Dae-Hyun;Park, Hong-Gyu;Kim, Young-Hwan;Kim, Byoung-Yong;Ok, Chul-Ho;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.10 no.4
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    • pp.140-142
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    • 2009
  • We have investigated the continuous pretilt angle generation for liquid crystals using a rubbing treated mixture layer consisting of homogeneous and homeotropic polyimides. Various pretilt angles in the range from $0^{\circ}$ to $60^{\circ}$ were achieved as a function of the concentration of homeotropic PI. The transmittance characteristics used to measure the pretilt angle showed that the pretilt angles were measured with a high reliability. We observed uniform liquid crystal alignment on the rubbing treated mixture layer.

Process Optimization of Composite-based Capacitor for LC Resonant Circuits

  • Mun, Sei-Young;Cha, Cheol-Ung;Choi, Jong-Chan;Lim, Seung-Ok;Hong, Sang-Jeen
    • Journal of the Speleological Society of Korea
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    • no.80
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    • pp.21-24
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    • 2007
  • The need for high-frequency decoupling capacitors to supply the transient current requirements to high-speed devices is ubiquitous in current microelectronics applications. Even though materials and their processes have already been developed in terms of their performances, low manufacturing cost cannot be overemphasized in current microelectronics industry. For this reason, we revisited low cost ceramic filled polymer integrated capacitor. Experiments were performed according to the design of experiment (DOE). The best recipe that has the optimized ratio of material composite was obtained using by response optimizer in Minitab. And also, high-frequency measurements were performed to get frequency dependent data using network analyzer.

Electrically controllable polymer-dispersed liquid crystal (전기적 스위칭이 가능한 고분자 분산형 액정 제작 및 동적 홀로그램 기록 특성)

  • 성기영;경천수;이영락;최병철;곽종훈;최옥식;이윤우
    • Korean Journal of Optics and Photonics
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    • v.10 no.6
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    • pp.494-499
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    • 1999
  • We report on the results of holographic transmission grating that can be controlled by the applied AC electric field. We have fabricated a polymer-dispersed liquid crystal material that composed of multifunctional acrylate monomer blended with the liquid crystal mixture E7. To investigate an electro-optic properties of fabricated HPDLC, diffraction efficienties (DE) are measured as a fuction of applied electric field and density of liquid crystal. Maximum DE of about 70% is obtained about 30 wt% of LC concentration at a zero field. We have also shown that optical image was recorded in the tllm, and then the reconstructive image was switchable with the applied electric fields. ields.

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Numerical Analysis of One Drop Filling Process with Photo-definable Spacer

  • Lee, Woo-Shik;Yoo, Gi-Chun;Jeon, Baek-Kyun;Kim, Choong-Sik;Kim, Ki-Taek
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.500-503
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    • 2002
  • In this paper, we demonstrate the deformation of TFT-LCD panel using numerical analysis based on the finite element method. To make better uniform cell gap and less stress at a photo-definable spacer (spacer), we have investigated process and design factors such as amount of liquid crystal (LC), spacer density, area, height, and material property. Furthermore we optimized design factors and achieved the robust design through the simulation.

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Structural Analysis of Black Common Bean (Phaseolus vulgaris L.) Anthocyanins

  • Choung, Myoung-Gun
    • Food Science and Biotechnology
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    • v.14 no.5
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    • pp.672-675
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    • 2005
  • Two anthocyanins were isolated from 1% HCl-20% methanol extracts of KG 97287 black common bean (Phaseolus vulgaris L.) using semipreparative, high-performance liquid chromatography (HPLC). The anthocyanins were identified using a combination of LC/ES-mass spectrometry (MS) and spectroscopic methods of UV-Vis, $^1H-$ and $^{13}C-$ nuclear magnetic resonance (NMR). The chemical structures of these two anthocyanins were elucidated as delphinidin 3-glucoside and petunidin 3-glucoside and their contents in KG 97287 black common bean seed coats were determined to be $2.614{\pm}0.11$ and $0.167{\pm}0.01\;mg/g$, respectively. These contents were lower than reported internationally and we recommend the introduction into Korea of high anthocyanin varieties of black common bean.

A Research for calculation FED of construction material according to conecalorimeter model (콘칼로리미터 화재모델을 적용한 건축 재료의 독성지수산정에 관한 연구)

  • Kim, Sung-Soo;Cho, Nam-Wook;Chun, Ji-Hong;Rie, Dong-Ho
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2011.04a
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    • pp.262-266
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    • 2011
  • 본 연구에서는 건축물 내장 재료에 대한 연소독성평가와 독성지수연구로써 FT-IR을 이용한 연소가스분석실험을 하였다. 독성지수를 산정하기 위한 실험의 화재모델로 콘 칼로리미터 화재모델(KS F ISO/TR 9122-4)을 사용하였으며 ISO 19702의 절차에 따라 FT-IR을 이용하여 건축 재료의 연소로부터 발생되는 가스의 분석을 수행하였다. 국제규격에서 제시하고 있는 몇 가지 독성지수 산정법 중 ISO 13344에서 규정하는 방법에 따라 FED 값을 산정하였으며, 30분간 시험동물에 노출 시 대상의 50%가 사망하는 농도인 $LC_{50}$을 기준으로 하여 3가지 재료의 독성지수화를 통해 상대적인 독성 위험도를 평가하였다.

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Indium Gallium Zinc Oxide(IGZO) Thin-film transistor operation based on polarization effect of liquid crystals from a remote gate

  • Kim, Myeong-Eon;Lee, Sang-Uk;Heo, Yeong-U;Kim, Jeong-Ju;Lee, Jun-Hyeong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.142.1-142.1
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    • 2018
  • This research presents a new field effect transistor (FET) by using liquid crystal gate dielectric with remote gate. The fabrication of thin-film transistors (TFTs) was used Indium tin oxide (ITO) for the source, drain, and gate electrodes, and indium gallium zinc oxide (IGZO) for the active semiconductor layer. 5CB liquid crystal was used for the gate dielectric material, and the remote gate and active layer were covered with the liquid crystal. The output and transfer characteristics of the LC-gated TFTs were investigated.

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Design of a Wide-Viewing-Angle OCB Mode with Wide-Band Wide-Viewing-Angle Quarter-Wave Plates

  • Lee, Seong-Ryong;Jhun, Chul-Gyu;Yoon, Tae-Hoon;Kim, Jae-Chang;Noh, Jeong-Dong;Suh, Dong-Hae;Lee, Jung-Yeal
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.345-348
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    • 2005
  • In this paper we propose a configuration for an optically compensated bend (OCB) mode using circular polarizers with wide-band wide-viewing-angle (WBWA) quarter-wave plates (QWPs). Parameters of LC material and compensation films are optimized for wide viewing angle characteristics and excellent spectral properties of the OCB mode.

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A Study on Electro-optical Characteristics of a-TN-LCD with Polarization of Orientation Film (배향막의 극성에 따른 a-TN-LCD의 전기광학특성에 관한 연구)

  • 서대식;이창훈
    • Electrical & Electronic Materials
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    • v.10 no.10
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    • pp.1011-1015
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    • 1997
  • In this paper we investigated the electro-optical characteristics of amorphous (a)- twisted nematic (TN)-liquid crystal display(LCD) on polymide (PI) surfaces with different molecular structure. It was found that the domaine size of a-TN-LCD on PI with high polarization is small compared to a-TN-LCD on PI with medium polarization. It is considered that the response time of a-TN-LCd contributes to surface effect between the substrate surfaces and the LC molecules. Finally we obtained that the viewing angle of a-TN-LCD on PI surfaces increases with decreasing the domain size.

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Alignment of Liquid Crystal on Ion-Beam Exposed ZnO Film

  • Hwang, Soo-Won;Yoon, Tae-Hoon;Kim, Jae-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.648-650
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    • 2009
  • We investigate nematic liquid crystal (NLC) alignment on ion-beam exposed ZnO films. ZnO is optically transparent material in the visible range. We optimized the deposition parameters such as deposition temperature and gas ratio for high transmittance and resistivity. Using ion-beam treated ZnO films, LC cells are fabricated and the conditions such as exposure energy and time for uniform alignment are found. The NLC molecules align parallel to the ion-beam exposure direction. The electro-optic and response characteristics show the possibility of application of this method in liquid crystal display.

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