• Title/Summary/Keyword: FFS mode

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A study on Electro-Optical Characteristics of the UV Aligned FFS Cell on the Organic Layer (유기막에 UV 배향한 FFS 액정셀의 전기광학특성)

  • Han, Jeong-Min;Hwang, Jeoung-Yeon;Kim, Byoung-Yong;Han, Jin-Woo;Kim, Jong-Hwan;Lee, Sang-Keuk;Oh, Yong-Cheul;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.278-279
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    • 2006
  • In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide Pl). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photo-alignment method were studied. An unstable V-T curve of UV-aligned FFS-LCD with conventional photo-alignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photo-alignment method (1h), and V-T curve of UV-aligned FFS-LCD with in-situ photo-alignment method was much stable comparing with that of other UV-aligned FFS-LCD's, As a result, more stable EO performance of UV-aligned FFS-LCD with in-Situ photo-alignment method is obtained than that of the other UV-aligned FFS-LCD's.

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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.

Temperature dependent electro-optical studies of liquid crystal in Fringe Field Switching (FFS), In-plane switching (IPS), and Patterned Vertical Alignment (PVA) modes

  • Jo, Eun-Mi;Srivastava, Anoop Kumar;Kim, Mi-Young;Kim, Sung-Min;Lee, Seung-Hee;Ji, Seung-Hoon;Lee, Gi-Dong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.320-323
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    • 2008
  • In this paper, electro-optical characteristic of Nematic Liquid crystal (LC) with varying temperature in different LCD modes, namely Fringe Field Switching (FFS), In-plane switching (IPS), and Patterned Vertical Alignment (PVA) modes are investigated and compared. Electro optic me asurements suggest that rate of change of transmission with temperature in FFS mode was lowest and much more thermally stable as compared to IPS and PVA m odes. However the electro-optical characteristic of patterned vertical alignment (PVA) mode was most affected by changing temperature. The measured threshold voltage was found to be much more thermally stable in FFS and IPS modes than that of PVA mode.

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A High Quality Fringe-Field Switching Display for Transmissive and Reflective Type

  • Lee, Seung-Hee;Choi, Soo-Han
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.5-6
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    • 2000
  • Fringe-field switching (FFS) technology exhibiting a high image quality has been developed. In this paper, one pixel concept, manufacturing process, materials, and electro-optic characteristics of FFS mode comparing with conventional in-plane switching mode, and its possible application to reflective type will be discussed.

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Electro-optic Characteristics of the Fringe-Field Switching Liquid Crystal Mode, Status of Applications, and Future Issues (Invited Paper) (Fringe-Field Switching (FFS) 액정 소자의 전기광학 특성, 응용 현황 및 향후 이슈)

  • Lim, Young Jin;Kim, Dae Hyung;Kim, Jin-Hyun;Kim, Yong Hae;Ahn, Seon Hong;Lee, Seung Hee
    • Korean Journal of Optics and Photonics
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    • v.25 no.6
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    • pp.301-310
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    • 2014
  • Recently, the fringe-field switching (FFS) mode in liquid crystal displays has been used mainly for high image quality and high-resolution liquid crystal displays (LCDs). In this review paper, the fundamental switching principle of the FFS mode, with its excellence over other LC modes in electro-optic performance, will be described. In addition, the development history, present technical issues, and future of the FFS LCD will be discussed.

Study on electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy according to the magnitude of dielectric anisotropy (양의 액정을 사용하는 FFS mode에서 액정의 유전율 이방성에 따른 전기 광학 특성 연구)

  • An, Young-Joo;Park, Ji-Woong;Jung, Jun-Ho;Lee, Hee-Kyu;Lee, Seung-Eun;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.399-400
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    • 2008
  • The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

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A High Quality Fringe-Field Switching Display for Transmissive and Reflective Types

  • Lee, Seung-Hee;Hong, Seung-Ho;Jeong, Yeon-Hak;Kim, Hyang-Yul
    • Journal of Information Display
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    • v.1 no.1
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    • pp.9-13
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    • 2000
  • In liquid crystal displays, the display mode that represents initial liquid crystal alignment and method of applying voltage, mainly determines the image quality of display. Recently we have developed the fringe-field switching (FFS) mode exhibiting high image quality. In this paper, a pixel concept, manufacturing process, materials, and electro-optic characteristics of the FFS mode comparing with conventional in-plane switching mode, and its possible application to reflective type are discussed.

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A Single Gap Transflective Display using Fringe Field Switching Mode (FFS(Fringe Field Switching)모드를 이용한 단일갭 반투과형 액정 디스플레이)

  • Chin, Mi-Hyung;Jeong, Eun;Lim, Young-Jin;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.388-389
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    • 2007
  • A transflective liquid crystal displays driven by fringe field switching mode of new concept is being suggested. The FFS mode is known to have the different twist angle distribution at the position when an operating voltage is applied. We make the cell design by using the different twist angle which has some region decided on transmissive region and other region used to reflective region. By optimizing simulation condition in the concept, we proposed new tansflective LCDs using FFS mode with single gap and single gamma characteristics.

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Film Compensation based on Discotic Film in Fringe Field Switching Mode

  • Hwang, Seong-Han;Jung, Byoung-Sun;Kim, Seong-Su;Lee, Seung-Hee;Lee, Gi-Dong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.527-530
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    • 2007
  • Film compensation to suppress a light leakage in the dark state of fringe-field switching (FFS) at off normal direction was performed by optimizing retardation value of discotic (negative A) and TAC films including in-plane switching (IPS). The normal FFS mode shows wide viewing angle characteristics that region of CR 10:1 is over $70^{\circ}$ of polar angle in all directions. The optimized FFS cell exhibits much better performances than other methods do in terms of CR and color uniformity.

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New Edge Structure of a Pixel Electrode for Improving the Transmittance of the Fringe Field Switching(FFS) Mode LCD (FFS모드의 투과율 향상을 위한 새로운 화소전극 구조제안)

  • Lee, Won-Jun;Park, Woo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.11
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    • pp.983-990
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    • 2007
  • In this study, we propose a new pixel edge shape of the fringe field switching(FFS) mode which ensures more stable movement of liquid crystal molecules and higher transmittance at the edge part. the electro optical properties were calculated 3-dimensionally using by commercially available "Techwiz LCD". From the simulation results, we showed that the dynamic stability of liquid crystal molecules was obtained in a new pixel structure. We also revealed that the transmittance of the new pixel structure increased more than 6 % compared to that of the conventional pixel structure.