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

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A Study on Response Characteristics of TN Cell on a Polyimide Surface (폴리이미드 표면에서의 TN 셀의 응답 특성에 관한 연구)

  • 황정연;전용제;정연학;서대식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.808-811
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    • 2002
  • We investigated response characteristics of twisted nematic (TN) cell with different nematic liquid crystals (NLCs) and cell gap d on a rubbed polyimide (PI) surface. High transmittance and fast response time of the TN cell on the rubbed PI surface were achieved by using high birefringence (Δn) and low cell gap d. The response time of TN cell on the rubbed PI surface was measured 5.1 ms. The transmittance and response time of the TN cell on the rubbed PI surface decreased with decreasing Δnd.

Electro-optical Characteristics of Twisted Nematic(TN)-LCD using New Ion Beam Equipment (새로운 이온빔장치를 사용한 Twisted Nematic-LCD의 전기광학특성)

  • Kim Sang-Hoon;Hwang Jeoung-Yeon;Jang Mi-Hye;Kim Gwi-Yeol;Seo Dae-Shik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.6
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    • pp.547-551
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    • 2006
  • We studied liquid crystal (LC) alignment with ion beam (IB) on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide surface using obliquely ion beam (IB) exposure with new IB type equipment. A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the polyimide surface was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-LCD on polyimide surface. Also, the EO characteristics of the ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using new type IB equipment is same or more superior than ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using Kaufman-type Ar ion gun.

Study on Electro-optic Characteristics and Dynamic Stability Depending on the Pretilt Angle for the Twisted Nematic(TN) and Fringe-field Switching(FFS) Mode (TN 모드와 FFS 모드에서 Pretilt Angle이 전기 광학 특성 및 동력학 안정성에 미치는 영향에 관한 연구)

  • Kim, M.S.;Jung, Y.H.;Kim, H.Y.;Kim, S.Y.;Lee, S.H.
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.11
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    • pp.1234-1240
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    • 2004
  • We studied on the electro-optic characteristics and dynamic stability according to an undesirably defined pretilt angle induced in high step coverage of pixel area for the Twisted Nematic (TN) / Fringe-Field Switching (FFS) mode. In case of the TN mode, LC directors twist reversely near the edges of thin-film-transistor and black matrix where the pretilt angle of the LC is not well defined. Therefore, the voltage-dependent dynamics of the LC in TN mode is unstable and shows the bad electro-optic characteristics. On the other hand, in case of the FFS mode, the LCs are twisted parallel to the bottom substrate by fringe electric field and the electro-optic characteristic is not influenced by the pretilt angle of the LC which is not well defined.

Fast Switching of Twisted Nematic Liquid Crystals Display Based on a High-K Yttrium Oxide (고유전율 Yttrium Oxide을 이용한 네마틱 액정 디스플레이의 고속 응답 전기-광학 특성)

  • Jung, Yoon Ho;Jeong, Hae-Chang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.4
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    • pp.302-306
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    • 2019
  • We investigated a solution-derived $Y_2O_3$ film treated by ion beam (IB) irradiation as a liquid crystal (LC) alignment layer. With IB irradiation, homogeneous LC alignment was achieved irrespective of the annealing temperature. To verify the effect of IB irradiation, we conducted surface analyses such as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). As $Y_2O_3$ is a high-k material, the electro-optical properties of the twisted nematic (TN) cells were superior to those of conventional TN cells based on a rubbed polymer, with an LC rising time of 4.1ms and falling time of 2.9ms. The IB-irradiated $Y_2O_3$ is a good alternative as an alignment layer for fast-switching TN LC displays.

Study on Electro-optic Characteristics of Fringe-field Switching Twisted Nematic Mode using a Liquid Crystal with Negative Dielectric Anisotropy (유전율 이방성이 음인 액정을 이용한 Fringe-field Switching Twisted Hematic 모드의 전기광학 특성 연구)

  • 송일섭;신성식;이종문;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.5
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    • pp.530-535
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    • 2004
  • We have studied 90$^{\circ}$ twisted nematic mode switching by fringe electric field(F-TN mode) using a liquid crystal (LC) with negative dielectric anisotropy. In the device, two polarizers are parallel each other, electrodes exist only on bottom substrate, and one of rubbing direction is coincident with polarizer axis. Therefore, the cell shows a black state before a voltage is applied. With a bias voltage generating fringe-electric field, the LC twists perpendicular to fringe electric field such that the LCs are almost homogeneously aligned except near the bottom surface since the negative type of the LC is used. Consequently, the new device exhibits much wider viewing angle than that of the conventional TN mode due to in-plane switching and relatively high transmittance since the LC director above whole electrode area aligns parallel to the polarizer axis.

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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Effects of Liquid Crystal Alignment on the Electro-Optical Characteristics of a-TN-LCD (a-TN-LCD의 전기광학특성에 미치는 액정배향의 효과)

  • 서대식;이창훈;황율연;이보호;이승희;김향율
    • Electrical & Electronic Materials
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    • v.10 no.1
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    • pp.15-19
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    • 1997
  • The characteristics of the response time and the viewing angle on twisted nematic (TN) liquid crystal display (LCD) and amorphous (a)-TN-LCD without rubbing were investigated. To measure the tansmission-voltage, response time, and viewing angle characteristics, we prepared three kinds of LC cells and then studied the surface liquid crystal alignment effect. It was found that the response time on A-TN-LCD was fast compared to the TN-I-CD, and the weak anchoring strength was attributed to the fast response time on a-TN-LCD. Also, we obtained the wide viewing angle characteristics on a-TN-LCD. The liquid crystal alignment of LCD device for electro-optical characteristics is discussed in the present paper.

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Electro-optic Characteristic of Twisted Nematic Mode using a Liquid Crystal Dispersed Carbon Nanotubes (탄소 나노 튜브가 분산된 액정을 이용한 TN 모드의 전기 광학 특성 연구)

  • Baik, In-Su;Jeon, Sang-Youn;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.05a
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    • pp.114-117
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    • 2005
  • We have fabricated twisted nematic (TN) cell doped by carbon nanotubes (CNTs). The CNTs with a minute amount of doping do not perturb the liquid crystal orientation in the off- and on-state. The hysteresis studies of voltage-dependent transmittance and capacitance under ac and dc electric field show that the amount of residual dc, which is related to image sticking problem in liquid crystal displays, is greatly reduced due to ion trapping by CNTs.

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Study on the residual DC characteristic of Twisted Nematic liquid Crystal Display on the Polyimide Surface by the Thermal Stress (폴리이미드 표면에서의 열적 스트레스에 의한 TN셀의 잔류 DC 특성 연구)

  • Bae, Yu-Han;Kim, Sang-Hoon;Hwang, Jeoung-Yeon;Kang, Hyung-Ku;Lee, Whee-Won;Kim, Jong-Hwan;Kim, Young-Hwan;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.451-452
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    • 2005
  • In this study, the threshold voltage and the response time of thermal stressed TN-LCDs showed the same performances on none thermal stressed TN-LCDs. There was little change in TN cells. Also, while increasing thermal stress time, the transmittances of TN-LCDs on the rubbed PI surface were almost the same, But the thermal stability of TN cell was deteriorated.

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EO performance of TN cell on the inorganic films surface using DuoPIGatron ion source on NDLC thin film (무기박막표면에 DuoPIGatron 이온소스를 이용한 TN-LCD 셀의 전기광학 특성)

  • Kim, Byoung-Yong;Hwang, Jeoung-Yeon;Kim, Sang-Hun;Han, Jung-Min;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.432-433
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    • 2006
  • Electro-optical (EO) characteristics of twisted nematic (TN) - liquid crystal display (LCD) on the NDLC thin film using obliquely ion beam (IB) exposure as new ion beam (IB) type system (DuoPIGatrion ion source). A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the NDLC thin film was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-cell on polyimide surface ; the stable VT curve in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained. and the fast response time in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained.

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