• Title/Summary/Keyword: twisted nematic(TN)

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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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    • v.12 no.1
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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.

Twisted Nematic LC Modulator for TFT Array Inspection

  • Bae, B.S.;Park, D.H.;Lee, H.K.;Lee, S.E.;Kim, S.H.;Jeong, D.H.;Rho, B.G.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.290-292
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    • 2007
  • A twisted nematic type liquid crystal electro-optic modulator (TN-LC modulator) was developed. The modulator used single polarizer and the reflection on-off ratio was maximized by optimization of twist angle and retardation of liquid crystal cell. The TNLC modulator shows better sensitivity and response time than conventional liquid crystal modulator.

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Characteristic confirm of Compensated Film Characteristics using Reactive Rod-like Mesogen in Twisted Nematic mode (TN mode에서의 Reactive Rod-like Mesogen을 이용한 보상필름의 특성 확인)

  • Jeon, Eun-Jeong;Kwon, Dong-Won;Kang, Byeong-Gyun;Lim, Young-Jin;Kim, Jong-Hoon;Seong, Hyeon-Jun;Lee, Myong-Hoon;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.271-272
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    • 2009
  • We fabricated a hybrid aligned film using reactive rod-like mesogen to reduce light leakage of twisted nematic(TN) cell in off-axis of the dark state. We proved that the fabricated compensation film has hybrid alignment by changing phase retardation according to polar angle. In this paper, we confirmed characteristics of compensation film through simulation results and found the matching factor of simulation results and experimental result. In result, the maximum pretilt angle of hybrid compensated film is $19^{\circ}$ which has phase retardation 0.1445.

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Electrode-Optic Characteristics of Fringe-field driven Twisted Nematic Mode using a Liquid Crystal with Negative Dielectric Anisotropy (유전율 이방성이 음인 액정을 이용한 fringe-field driven Twisted Nematic 모드의 전기광학 특성)

  • Song, I.S.;Shin, S.S.;Song, S.H.;Kim, H.Y.;Rhee, J.M.;Lee, S.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1054-1057
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    • 2003
  • We have studied $90^{\circ}$ twisted nematic (TN) mode driven by fringe electric field, where two polarizers are parallel each other such that the cell shows a black state before a voltage is applied. According to the studies by computer simulation for a LC with negative dielectric anisotropy, the LC twists perpendicular to the horizontal field direction of fringe electric field and the degree of tilt angle is very low, when a voltage is applied. Therefore, the new device exhibits wide viewing angle characteristic due to in-plane switching and high transmittance since the LC director aligns parallel to the polarizer axis.

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Effect of Carbon Nanotube Concentrations on Residual DC of a Twisted Nematic Liquid Crystal Cell (탄소 나노 튜브 함량에 따른 TN 액정 셀의 잔류 DC 연구)

  • Baik, In-Su;Park, Kyung-Ah;Jeon, Sang-Youn;An, Kay-Hyeok;Lee, Seung-Hee;Lee, Young-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.297-298
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    • 2005
  • We have fabricated twisted nematic (TN) liquid crystal cells doped by carbon nanotubes (CNTs) with different CNT wt. %. With a minute amount doping, multi-walled CNTs did not perturb the liquid crystal orientations at the off- and on-state. The hysteresis studies of voltage-dependent capacitance (V-C) under the influence of electric field generated by ac and dc voltage show that the residual do, which is tightly related to image sticking problem in liquid crystal displays, is greatly reduced due to ion trapping by CNTs. Also, the V-C hysteresis shows dependency of capacitance on concentration of multi-walled CNTs.

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Electro-Optical Performances of Flexible Liquid Crystal Display on Twisted Nematic Mode according to Cell Gap (셀갭 변화에 따른 Flexible 기판 TN-LCD의 전기광학특성)

  • Kang, Hee-Jin;Hwang, Jeoung-Yeon;Lee, Whee-Won;Kim, Jong-Hwan;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.289-290
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    • 2005
  • We have investigated the electro-optical (EO) performances of the flexible liquid crystal display (LCD) on twisted nematic (TN) mode according to variation of cell gap in comparison with glass LCD. There were four kinds of cells which were having cell gaps of 3$\mu$m, 4$\mu$m and 5$\mu$m, especially the lowest 2$\mu$m on flexible and glass substrates separately. The EO performances of the flexible cells on the rubbed potyimide (PI) were almost the same those of glass cells. The response time of flexible cells was shorter than that of glass cells but the alignment of liquid crystal (LC) of flexible cells was weaker than that of glass cells. The residual DC of flexible cells was on the increase like that of glass cells in compliance with lowering cell gap.

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Study on of polarity effect on alignment film in transcription-aligned TN-LCD (전사배향 TN-LCD 에서의 배향막의 극성효과에 관한 연구)

  • Kim, Jin-Ho;Seo, Dae-Shik
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1812-1814
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    • 1999
  • The effects of polarity of the polymer on transcription-aligned twisted nematic (TN)-liquid crystal display (LCD) on various the polyimide (PI) surfaces were investigated. The monodomain alignment of nematic (N)LC is obtained in cells fabricated by transcription alignment method on PI surface with medium polarity. The LC alignment using transcription alignment method is attributed to polarity of the polymer. The threshold voltage of transcription-aligned TN-LCD decreases with increasing the polarity of the polymer on three kinds of the PI surfaces. The threshold voltage of transcription-aligned TN-LCD on PI surface with high polarity is almost the same compared to rubbing-aligned TN-LCD. The response time of transcription-aligned TN-LCD decreases with the increasing the polarity of the polymer on all PI surfaces. The decay time of transcription-aligned TN-LCD is slow compared with the rubbing-aligned TN-LCD.

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Pretilt Angle Generation of Photo-aligned TN-LCD Using Oblique Non-polarized UV Light Irradiation on Polymer Surface (경사진 자외선조사를 이용한 네마틱액정의 프리틸각의 발생 및 광배향 TN-LCD의 전기광학특성)

  • 서대식;한정민;박두석
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.10
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    • pp.911-917
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    • 1998
  • In this paper, we have investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet(UV) light irradiation polyimide (PI) surface. It was found that the monodomain alignment of the NLC is obtained with an angle of incidence of 70∼85。 on PI surface. It is considered that the monodomain alignment of NLC is attributed to anisotropic of NLC is about 3。 with and angle of incidence of 70∼75。. Finally, we observed that the voltage-transmittance, response time, and voltage-holding-ratio(VHR) characteristics of photo-aligned twisted nematic(TN)-LCD with and angle of incidence of 85。 on PI surface were almost same compared to rubbing -treated TN-LCD.

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Liquid crystal alignment on the inkjet printed polyimide by using new alignment method

  • Hwang, J.Y.;Wonderly, H.;Chien, L.C.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.506-508
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    • 2007
  • We studied the nematic liquid crystal (NLC) alignment capability with a new alignment method utilizing an inkjet printed polyimide (PI) layer. A good, uniform LC alignment was achieved by the good PI printing using a new alignment method. The pretilt angle generated on the printed PI layer using the alignment method was almost the same as that on printed PI layer using rubbing alignment method. In addition, the good electro-optical performances of the new aligned twisted nematic (TN) cell with printed PI surface was obtained

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