• 제목/요약/키워드: Nematic Liquid crystal

검색결과 519건 처리시간 0.022초

Synthesis and physical properties of 2-(4-alkylcyclohexylphenyl)5-alkyl (fluoro)-1,3,2-dioxaborinane derivatives their use in liquid crystals

  • Lee, Jae-Ho;Park, Dae-Won;Kim, Jin-Ha;Kim, Yong-Bae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.385-388
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    • 2005
  • 2-[4-(4-alkylcyclohexyl)-phenyl]-5-alkyl-(1,3,2)-dioxaborinane and Fluoro-substituted 1,3,2-dioxaborinane vatives were synthesized and their physical properties were measured. synthesized compound were showed nematic isotropic transition.

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Dielectric and Electro-Optical Properties of Ceramic Nanoparticles Doped Liquid Crystals

  • Porov, Preeti;Chandel, Vishal Singh;Manohar, Rajiv
    • Transactions on Electrical and Electronic Materials
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    • 제17권2호
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    • pp.69-78
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    • 2016
  • Liquid crystals are important materials because of their applications in display technology and many other scientific applications. Different mixtures of liquid crystals and their doped samples have gained interest because a single liquid crystal compound cannot fulfill all the required parameters for the display application. The doping can be accomplished with dyes, polymers, or composite nanoparticles among other substance. The addition of nanoparticles can modify the physical properties of the host liquid crystal and enhances the performance of electro-optical devices. The present study is focused on investigations of possible changes in dielectric and electro optical properties of liquid crystals caused by doping with ceramic nanoparticles. Including smaller nanoparticles were found to be better candidates for use in suppressing the unwanted ion effects in liquid crystal displays.

이온빔 조사각도에 따른 액정의 프리틸트각과 전기 광학적 특성 (Pretilt angle and EO Characteristics of Liquid Crystal via Ion-beam Irradiation Angles)

  • 이강민;이원규;오병윤;김병용;한진우;전지연;한정민;이상극;서대식
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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    • pp.44-44
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    • 2008
  • To date, rubbing has been widely used to align LC molecules uniformly. Although rubbing can be simple, it has fundamental problems such as the generation of defects by dust and static electricity, and difficulty in achieving a uniform LC alignment on a large substrate. Therefore, non contact alignment has been investigated. Ion beam induced alignment method, which provides controllability, nonstop process, and high resolution display. In this study, we investigated liquid crystal (LC) alignment with ion beam (IB) that non contact alignment technique on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide under various ion beam angles. In this experiment, Polyimide layer was coated on glass by spin-coating and Voltage-transmittance(VT) and response time characteristics of the TN cell were measured by a LCD evaluation system. The good characteristics of the nematic liquid crystal (NLC) alignment with the ion beam exposure polyimide surface was observed. The tilt angle of NLC on the PI surface with ion beam exposure can be measured under $1^{\circ}$ for all of irradiation angles. In addition, it can be achieved the good EO properties, and residual DC property of the ion beam aligned TN cell on polyimide surface.

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SiC 박막을 이용한 액정의 수직배향효과 (Homeotropic Alignment Effect of Liquid Crystal on the SiC Thin Film Layer)

  • 박창준;황정연;강형구;김영환;서대식;안한진;김경찬;김종복;백홍구;임성훈;박규창;장진
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.502-505
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    • 2004
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiC (Silicon Carbide) thin film. SiC thin film exhibits good chemical and thermal stability. The good thermal and chemical stability make SiC an attractive candidate for electronic applications. A homeotropic alignment of nematic liquid crystal by ion beam (IB) 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. The good LC alignment is maintained by the ion beam alignment method on the SiC thin film surface until annealing temperature of $300^{\circ}C$. Consequently, homeotropic alignment effect of liquid crystal and the good thermal stability by the ion beam alignment method on the SiC thin film layer can be achieved.

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저가형 CSTN-LCD 동영상 프로세서 설계 (Implementation of Motion Picture Processor for Low-cost CSTN-LCD)

  • 김용법;최명렬
    • 한국멀티미디어학회논문지
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    • 제9권8호
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    • pp.963-970
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    • 2006
  • 본 논문에서는 저가형 CSTN-LCD(Color Super-Twisted Nematic Liquid Crystal Display)에 사용하는 동영상 프로세서를 제안한다. 제안된 프로세서는 SFP(SubFrame Pattern) 기법을 적용하여 계조 확장을 할 뿐 아니라 플리커(flicker)현상을 제거하였고 BFI(Black Field Insertion) 기법을 적용하여 액정의 응답시간을 보상하였다. 그리고 화질 향상을 위한 에지 강조 기법과 보간기법을 적용하였다. 하드웨어 구조는 FPGA 프로토타입 보드를 사용하여 검증하였다. 제안된 동영상 프로세서는 PDA(Personal Digital Assistants), 모바일 폰과 PMP(Portable Multimedia Player) 등에 사용되어 질 수 있다.

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Homeotropic Alignment Effect of a Nematic Liquid Crystal on Oblique Deposited SiOx Thin-film with e-beam Evaporation

  • Choi, Dai-Seub
    • Transactions on Electrical and Electronic Materials
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    • 제8권6호
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    • pp.274-277
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    • 2007
  • In this study, liquid crystal(LC) aligning capabilities for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method were investigated. Also, the control of pretilt angles and thermal stabilities of the nematic liquid crystal(NLC) treated on $SiO_x$ thin film were investigated. A high pretilt angle of about $86.5^{\circ}$ was obtained, and also the suitable pretilt angle of the NLC on the $SiO_x$ thin film at $10{\sim}50nm$ thickness with e-beam evaporation can be achieved. The uniform LC alignment and good thermal stabilities on the $SiO_x$ thin film surfaces with electron beam evaporation can be achieved. It is considered that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation.

In-situ 광배향법을 이용한 Flexible TN 셀의 액정배향 효과 (Liquid Crystal Alignment Effect using in-situ Photoalignment on Flexible TN cell)

  • 남기형;황정연;이휘원;최면길;서동학;김영환;서대식
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.506-509
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    • 2004
  • We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with in-situ photoalignment method on polyimide (PI) surfaces using thin plastic substrates. The LC aligning capabilities and pretilt angle of the thin plastic substrates by in-situ photoalignment method were better than that of the glass substrate by general photoalignment. Also, the LC pretilt angle increased with increasing heating temperature and exposure time. And EO characteristics of photoaligned TN-LCDs using in-situ photodissociation method on glass substrate and on plastic substrate are also excellent.

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SiO 박막을 이용한 액정배향 효과 (Liquid Crystal Alignment Effects Using a SiO Thin Film)

  • 강형구;황정연;박창준;서대식;안한진;김경찬;김종복;백홍구
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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    • pp.198-201
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    • 2004
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiO thin film. The homogenous alignment can be obtain어 using ion beam (IB) exposure on the SIO thin film, when positive type NLC ($Delta\varepsilon$>0) was injected However, the homeotropic alignment can be obtained using ion beam (IB) exposure on the SiO thin film, when negative type NLC ($\Delta\varepsilon$>0) was injected The LC aligning ability on the SiO thin film depends on the dielectric anisotropy type of LC. It will be discussed.

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유기절연막으로의 경사진 이온빔조사가 유기막 표면에서의 편광발생과 액정배향에 미치는 영향에 관한 연구 (Study of Liquid Crystal Alignment and Polarization-dependence on organic surface with slanted ion beam irradiation)

  • 한정민;최대섭;황종선
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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    • pp.15-16
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    • 2010
  • We used Brewster's Law to examine the mechanism of liquid crystal (LC) alignment on an organic insulation layer when subjected to ion-beam irradiation. Brewster's Law implies that the maximum rate polarized rayon a slanted insulation layers on the substrate and it illustrates the dependence of polarization and themechanical structure on the ion beam irradiation process. The pretilt angle of nematic LCs on the organic insulation surface was about $1.13^{\circ}$ for an ion beam exposure of $45^{\circ}$ for 1 minute at 1800eV. This shows the dependence of LC alignment on the polarization ratio in a slanted organic insulation layer. We also discussed the electro-optical characteristic of twisted nematic (TN) LCD using ion beam irradiation on organic overcoat layer.

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Liquid Crystal Alignment Effect on the Inorganic Thin Film by Sputtering and using Ultraviolet Exposure Mothod

  • Hwang, Jeoung-Yeon;Kang, Hyung-Ku;Seo, Dae-Shik;Oh, Byeong-Yun;Ham, Moon-Ho;Myoungr, Jae-Min
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.460-463
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    • 2005
  • We studied the nematic liquid crystal (NLC) alignment capability by the Ultraviolet (UV) alignment method on a a-C:H thin -film , and investigated electro-optical performances of the UV aligned twisted nematic (TN)- liquid crystal display (LCD) with the UV exposure on a-C:H thin film surface. A good LC alignment by UV irradiation on a a-C:H thin -film surface was achieved. Monodomain alignment of the UV aligned TN-LCD can be observed. The good electro-optical (EO)characteristics of the UV aligned TN-LCD was observed with oblique UV exposure on the a-C:H thin film surface for 1min.

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