• 제목/요약/키워드: Liquid crystal mode

검색결과 270건 처리시간 0.029초

Electro-Optical and Switching Behavior of In-plane Switching Twisted Nematic Liquid Crystal Display

  • Kimura, Munehiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1092-1095
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    • 2003
  • A driving mechanism and excellent features for an in-plane switching twisted nematic liquid crystal mode (IT mode) that could possibly improve the viewing-angle and color shift characteristics and the cell gap error tolerance is proposed. .It is important that the surface azimuthal anchoring strength of the liquid crystal cell differs at the upper and lower substrates. Furthermore. as a rubbing-free LCD. amorphously aligned in-plane switching twisted nematic mode (a-IT mode) is also demonstrated.

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Dual Frequency Switchable Flexoelectric Cholesteric Devices

  • Chien, Liang-Chy;Shi, Lei
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.105-108
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    • 2005
  • We demonstrate an electro-optical device based on the flexoelectric effect of a short-pitched cholesteric liquid crystal. By using a dual-frequency switchable nematic, a small amount of chiral dopant and a small amount of phase-separated polymer localized on the surface, we were able to create a device that operates in amplitude (flexoelectric) and phase(dielectric) modes. At high frequency the dual frequency liquid crystal suppresses the phase mode at higher voltage, which improves the switching speed, and thereby preserving the in-plane-switching mode.

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수직 배향된 액정 셀과 원 편광판을 이용한 단일 갭 반투과형 액정 디스플레이 연구 (Study on Single Gap Transflective Liquid Crystal Display using the Vertical Alignment Mode and circular polarizer)

  • 김진호;진미형;정은;임영진;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.401-402
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    • 2008
  • We proposed a single gap transflective liquid crystal display (LCD) using a vertically aligned (VA) liquid crystal cell and circular polarizer. The conventional VA transflective LCDs have problems that there required several compensation films and voltage-dependent transmittance and reflectance curves do not match each other. To solve these problems, we used circular polarizer and optimized the condition of insulator thickness in the transmissive part and reflective part. Also, we used the patterned vertical alignment (PVA) mode for wide viewing angle in transmissive part. Consequently, this device realized transflective LCD with a single cell gap and single gamma curve.

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디스플레이 응용을 위한 액정 모드 (Liquid Crystal Modes for Display Applications)

  • 김정욱;윤태훈
    • 한국광학회지
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    • 제24권4호
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    • pp.168-175
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    • 2013
  • 정보디스플레이 기술은 디지털 정보화 사회를 혁신적으로 변화시킨 원동력이다. 액정 디스플레이는 가장 대표적인 평판 디스플레이로서 저소비전력, 경량, 박형 등의 장점을 앞세워 소형에서부터 대형에 이르기까지 다양한 응용분야에 널리 사용되고 있다. 하지만, 더욱 고성능의 디스플레이를 구현하기 위해 끊임없이 연구가 지속되고 있다. 본 논문에서는 액정 디스플레이의 구조 및 구동원리에 대해 설명하고, 액정 모드 기술에 대해 본 연구실에서의 연구를 중심으로 소개하고자 한다.

Synthesis and Properties of New Aromatic Polyimides for IPS-mode

  • Kim, Y.B.;Park, J.C.;Park, D.J.;Son, K.C.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.792-795
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    • 2006
  • In-plane-switching (IPS)-mode LCD is one of the most useful technologies for a broad range of viewing angles. To apply for IPS-LCDs, we synthesized novel homogeneous alignment materials, changing dianhydrides (BTDA and BPDA) and bridged diamines (ODA and PACM). We measured their pre-tilt angles using the crystal rotation method with positive LC and their surface properties.

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Vertical Alignment Nematic Liquid Crystal Display with Patterned Electrode Using Positive Liquid Crystal Materials

  • Shin, Hun-Ki;Yoon, Tae-Hoon;Kim, Jae-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.499-501
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    • 2007
  • We propose a vertical-alignment liquid crystal display with patterned electrodes using a positive dielectric anisotropic liquid crystal. In this structure, the threshold and on-state voltages are reduced compared with previous vertical-alignment configuration with positive liquid crystal.

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Development of Fast Response Time (16msec) in IPS Mode

  • Lim, C.S.;Lee, J.H.;Oh, C.H.;Choi, H.C.;Lee, Seung-Eun;Jin, Min-Ok;Klasen-Memmer, M.;Tarumi, K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.68-71
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    • 2003
  • To be able to show moving images without visual problems like blurring and tailing, the response time of liquid crystal display (LCDs) must be improved. In this paper we will discuss our progress in improving the response time by optimizing the cell configuration and the use of new liquid crystal mixtures. A 20.1inch diagonal UXGA IPS TFT-LCD has been developed having a response time as fast as l-frame time (16msec) for white-black operation and less than 16msec in all gray levels without applying ODC (Over Driving Circuit). This is very important because one of the technology to reduce motion blurring, the use of scanning backlight is conditioned by 16msec for all grays. The excellent gray-to-gray response can be explained by virtue of fundamental characteristics of S-IPS mode and makes a good contrast with the results of VA mode.

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수평 배향된 네마틱 액정 모드들의 화질 특성 비교 (Comparisons of Image Quality Characteristics in Homogeneously Aligned Nematic Liquid Crystal Modes)

  • 정병선;김태현;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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    • pp.100-103
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    • 2005
  • Homogeneously aligned nematic liquid crystal modes are representatively the -FFS (fringe-field switching) mode using liquid crystal (-LC) with negative dielectric anisotropy, the +FFS mode and the IPS (in-plane switching) mode using +LC with positive dielectric anisotropy. In view of image quality evaluation standard of LCD, we compared characteristics of the brightness, the contrast ratio (CR) and color shift when the modes have respectively optimized phase retardation values $(d{\Delta}n)$. Consequently, in the most sensitively viewing angle of a man's physical vision, both FFS modes have advantage over the IPS mode from the brightness & the CR point of view. We are also confirmed that the +FFS mode out of them shows the smallest color shift according to all viewing directions in grey levels.

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Advanced Patterned Vertical Aligned Nematic Mode to Elevate Transmittance

  • Gwag, Jin Seog
    • Journal of the Optical Society of Korea
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    • 제18권1호
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    • pp.78-81
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    • 2014
  • This paper presents an advanced patterned vertical aligned nematic liquid crystal (APVA) mode as a way of improving the transmittance of the conventional patterned, vertically-aligned nematic liquid crystal (PVA) mode. The APVA was characterized by multi-electrodes, which play an important role in generating a horizontal electric field that prevents LC disclination in the vicinity of the middle region of electrodes between top and bottom slits in PVA mode. The proposed APVA mode focused on improving dramatically the transmittance with excellent image quality. In the simulation, the APVA mode improved the transmittance by more than 22%, compared to the conventional VA modes. Therefore, it is useful to upgrade the LCD display quality.

Optical Simulation of Viewing Angle Property of Biaxial Nematic Bent-Core Liquid Crystal

  • Yang, Seungbin;Lee, Ji-Hoon
    • Journal of the Optical Society of Korea
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    • 제20권4호
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    • pp.510-514
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    • 2016
  • The conventional liquid crystal displays (LCDs) have been using optically uniaxial liquid crystal (LC) medium and this often causes a significant image change at oblique viewing angles. We simulated the viewing angle properties of the biaxial nematic (Nb) phase of a bent-core liquid crystal (BLC) and compared the results with the vertically aligned (VA)- and the in-plane switching (IPS)-LCDs. The Nb phase of the BLC showed a smaller transmittance at the dark state as well as a greater contrast ratio at wide viewing angle. The viewing angle property of the Nb-mode without any compensation film was slightly superior to the IPS-mode with the compensation films eliminating the decross of the polarizers at oblique viewing angle.