• 제목/요약/키워드: Electro-optical properties

검색결과 236건 처리시간 0.024초

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.

Electro-optical Properties of Twisted Nematic Liquid Crystal Displays Fabricated with TIPS-pentacene Doping

  • Lee, Jin-Woo
    • Transactions on Electrical and Electronic Materials
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    • 제14권2호
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    • pp.82-85
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    • 2013
  • This paper introduces 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) doped liquid crystal (LC) alignment properties on a rubbed polyimide (PI) layer as a function of the doping concentration of TIPS pentacene. Pretilt angles, photomicrographs, and electro-optical properties of TIPS pentacene doped LCs were comparable to those of pure LCs. However, TIPS pentacene in a LC medium supported twisted nematic-liquid crystal displays (TN-LCDs) to improve electro-optical properties. The threshold voltages observed in the TN cells decreased as the TIPS pentacene concentration increased. In addition, suitable response times were observed in TN cells.

Electro-hydrodynamic 프로세스를 이용한 PMMA 마이크로 비드 제조방법에 대한 연구 (Research for fabricating micro-size PMMA beads using Electro-hydrodynamic process)

  • 박종하;이준희;김완두
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.1509-1514
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    • 2008
  • To fabricate microsized poly(methyl methacrylate)(PMMA) beads of uniform size and density on poly(ethylene terephthalate) (PET) fis, we introduce an electro spraying technique that uses a target electrode applied with an ac electric fid. Using the apparatus and various material properties, we could obtain uniform size PMMA beads which were deposited on the thin PET film. The optical properties, transmittance and light diffusivity of the fis electro sprayed with the PMMA were characterized. The results show that the sprayed beads appear to act as a good optical diffuser, like microlenses. To understand the effect of process variables, applied field conditions and rheological properties, the morphological pictures of the deposited particles were investigated through the optical and scanning electron microscope.

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Macroscopic Nonlinear Optical Properties of Tricyanopyrrolidene Chromophore Containing Amorphous Polycarbonate: Effect of Molecular Lateral Moiety in the Conjugative Structure

  • Cho, Min-Ju;Lee, Sang-Kyu;Jin, Jung-Il;Choi, Dong-Hoon
    • Macromolecular Research
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    • 제14권6호
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    • pp.603-609
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    • 2006
  • Tricyanopyrrolidene chromophores were prepared in order to compare their macroscopic nonlinear optical (NLO) properties with a conjugated structure through the long molecular axis. A thiophene or phenyl ring was tethered to an ethylenic bond; it may act as a lateral moiety to disrupt the planarity of a chromophore and lessen the electrostatic interaction. Thin film composites of these chromophores dissolved in amorphous polycarbonate (APC) were fabricated. Real time pole and probe method was employed to investigate the change of electro-optic (EO) signal during poling. The EO properties and their relaxation behaviors of the guest-host systems containing newly synthesized chromophores were investigated in detail.

전기가변 고분자 소재를 이용한 응용소자 (Electro-active Polymer and Dielectric Elastomer Technology for Haptic Interface, Muscular Enhancement, and Tunable Optical Components)

  • 윤재웅;박승구;문성철
    • 전자통신동향분석
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    • 제34권4호
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    • pp.108-116
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    • 2019
  • Electro-active polymers and dielectric elastomers have many intriguing properties that enable smart interfaces and electrically tunable optical systems, such as haptic feedback devices, artificial muscles, and expansion-tunable optical elements. These device classes are of great interest owing to their promising roles in next-generation technologies including virtual or augmented reality, human sensing and muscular enhancement, and artificial skins. In this report, we review basic principles, current state-of-the-art techniques, and future prospects of electro-active and dielectric elastomer technology. We describe chemical and physical properties of the most promising polymer substances, essential elementary architectures for artificial muscle-like functionalities, and their applications to haptic interfaces, muscular enhancement, and focus-tunable optical elements.

Electro-optical Properties of Twisted Nematic Liquid Crystal Cell with Silver Nanowire Network Electrodes

  • Jang, Kyeong-Wook;Han, Jeong-Min;Shon, Jin-Geun
    • Journal of Electrical Engineering and Technology
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    • 제12권1호
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    • pp.284-287
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    • 2017
  • This paper introduces liquid crystal (LC) alignment and its electro-optical properties in the LC cells with silver nanowire (AgNW) networks. The AgNW network was used as an electrode of LC cell as a substitute for an indium-tin-oxide (ITO) film. LC alignment characteristics in the LC cell using AgNW networks, which have two different sheet resistances of $60{\Omega}/m^2$ and $80{\Omega}/m^2$, were observed. The LC alignment characteristics including pretilt angle, LC alignment state, and thermal stability are similar irrespective of sheet resistance of AgNW network. However, twisted-nematic (TN)-LC cell normally operated when using AgNW network with sheet resistance of $80{\Omega}/m^2$. Electrooptical properties of TN-LC cell exhibited competitive performance compared to those of TN-LC cell based on conventional ITO electrode, which allow new approaches to replace conventional ITO electrode in display technology.

에멀전 방식의 고분자 분산형 액정의 전기 광학 특성에 미치는 액적 크기 분포의 영향 (Droplet Size Distribution Effect on the Electro-Optical Properties of Emulsion Type Polymer Dispersed Liquid Crystal)

  • 유희상;오남석;김안;권순범
    • 한국전기전자재료학회논문지
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    • 제28권7호
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    • pp.439-445
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    • 2015
  • We established the emulsion method using membrane filter with precise control of LC droplet distribution in PDLC. PDLC cells with various LC droplet size distributions such as single droplet sizes of $1.0{\mu}m$, $1.9{\mu}m$ and $3.5{\mu}m$, the mixture of two different LC droplet sizes and the mixture of three different LC droplet sizes were fabricated and the electro-optical properties of the emulsion type PDLC cells with various droplet size distribution were investigated. In the appropriate droplet size range, the PDLCs with the single droplet sizes distributions have good electro optical properties than those with the mixture of three different LC droplet sizes. In addition, the PDLC cells with the mixture of two different LC droplet sizes have the better electro optical properties than those with single droplet sizes distribution. The PDLC cell with dual droplet size distribution of $1.0+1.9{\mu}m$ shown the best electro optical properties than the PDLC cells with other size distributions. This method enabled us to find the proper LC droplet size distribution for achieving both high transmittance and contrast ratio.

폴리머 분산 액정의 전기 광학적 스위칭 특성에 대한 액정방울 크기의 효과 (Effect of droplet size on electro-optical switching properties of polymer dispersed liquid crystals)

  • 김인태;유연석
    • 한국광학회지
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    • 제17권1호
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    • pp.23-30
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    • 2006
  • 폴리머 분산 액정의 전기광학 스위칭 특성에 대한 액정 방울 크기의 효과를 실험적으로 연구하였다. 액정 방울의 크기는 상 분리를 위해 조사하는 레이저 광원의 세기와 LC/oligomer의 혼합 비율에 따라 변화되었다. 전기 광학적 스위칭 전압은 LC/oligomer의 혼합비율과 액정의 방울 크기에 크게 의존하였다. 실험 결과를 보면 상 분리용 조사 레이저광의 세기가 클 때 액정방울의 크기는 작아졌고 포화투과도 전압은 상승했지만 rise time은 짧아 졌다.

AC PDP의 전기광학적 특성에 미치는 동작 Gas Xex+Ne1-x의 영향 (The Effect of Working Gas Xex+Ne1-x on the Electro-optical Characteristics of AC PDP)

  • 박정후;유수복;이돈규;이해준;이호준;김재성
    • 전기학회논문지
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    • 제56권1호
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    • pp.142-146
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    • 2007
  • Nowadays, itis inevitable trend to use high Xe gas contents for increase luminous efficiency and luminance in plasma display panel. However, the increase of Xe gas contents causes the driving voltage, although the brightness is increase. In this paper, we study the characteristics of electro optical according to Xe gas contents and gas pressure. Electro-optical characteristics were investigated by the discharge voltage, luminance and luminous efficacy measurements, respectively. With some increasing Xe gas contents and pressure, the electro-optical properties increased. However, the characteristics of electro-optical begin to be saturated, when too high increased Xe gas contents and pressure.