• Title/Summary/Keyword: Liquid crystal mode

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Improvement of the response time and embodiment of the viewing angle in IPS mode (IPS-LCD에서의 표면액정배향효과가 시야각 특성과 응답속도에 미치는 영향)

  • 최재학;서대식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.65-68
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    • 1998
  • The mechanism of response time and viewing angle in in-plane switching ( IPS ) liquid crystal display ( LCD ) were investigated. The response time of photo-aligned IPS-LCD is fast compared with rubbing-aligned IPS-LCD on polyimide ( PI ) surface. The decay time $\tau$$\_$d/ is decreased with increasing the azimuthal anchoring energy A $\psi$ due to the steric interaction between the LC molecules and side chain of polymer. The viewing angle of IPS-LCD is increased by using photo-depolymerizatin method ; about ${\pm}$70$^{\circ}$at all direction.

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Study on Electro-opt ic Characteristics in the Optically Compensated Splay Cell with UV-curable Reactive Mesogen

  • Kim, Seong-Su;Jeon, Eun-Jeong;Lee, Myong-Hoon;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.327-329
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    • 2008
  • We have studied the optically compensated splay (OCS) mode using reactive mesogen monomer to reduce critical voltage, setting voltage and phase transition time from initial bend to splay state. The high pretilt angle from vertical alignment was formed through the polymerization of UV curable RM monomer at the surfaces. In this way, orientation of the LC with OCS can be achieved without setting voltage.

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Electrode optimization for single gamma in transflective in-plane switching liquid crystal cells

  • Lee, Gak-Seok;Kim, Jae-Chang;Yoon, Tae-Hoon;Kim, Young-Sik;Kang, Won-Seok;Kang, In-Byeong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.814-817
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    • 2006
  • In this paper we report the influence of rubbing direction and electrode distance to the voltage dependent transmittance in in-plane switching (IPS) mode. Moreover, we applied this to a transflective IPS cell to realize a single gamma characteristics both in the transmissive part and the reflective part..

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Simulation of Characteristics of Amorphous-Silicon Thin Film Transistor for Liquid Crystal Display Using the Mixed Simulator (혼합시뮬레이터를 사용한 액정 표시기용 비정질 실리콘 박막 트랜지스터의 특성 시뮬레이션)

  • 이상훈;김경호
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.12
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    • pp.122-129
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    • 1995
  • The most important feature of a-Si TFT is dense localized states such as dangling bonds which exist in tis bandgap. Electrons trapped by localized states dominate the potential distribution in the active a-Si region ,and influence the performance of a-Si TFT. In this paper, we describe the electrical characteristics of a-Si TFT with respect to trap distribution within bandgap, electron mobility and interface states using 2-Dimensional device simulator and compare the result of simulation with measurements. Using the mixed-mode simulator, we can predict the potential variation of pixel which causes residual image problem during the turn-off of a-Si TFT driving circuit. Therefore it is possible to consider trade-off between potential variation of pixel and turn-on current of a-Si TFT for the optimized driving circuit.

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Pretilt Angle Effects on Electro-Optic Characteristics of the Fringe-Field Switching (FFS) Mode

  • Hong, Seung-Ho;Lim, Kyu-Whan;Kim, Hyang-Yul;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.43-44
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    • 2000
  • The fringe-field switching (FFS) display is known to exhibit wide-viewing-angle and high transmittance. We have simulated pretilt effects on electro-optic characteristic of the device when a liquid crystal with positive and negative dielectric anisotropy is used. The results show that asymmetry in contour of luminance and light leakage in the dark state are increased but voltage-dependent transmittance curves remain about the same, as the pretilt angle increases to $10^{\circ}$.

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Implementation of a Low Power and Reduced EMI Signaling Circuit For a LCD Controller-to-Source Driver Interface

  • Choi, Chul-Ho;Choi, Myung-Ryul
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.167-168
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    • 2000
  • We propose a signaling circuit that can reduce power consumption and Electromagnetic Interference (EMI) in a Liquid Crystal Display (LCD) controller-to-source driver interface. The proposed signaling circuit consists of a coder/decoder that can minimize temporal bit transitions in a transmission line and a current-mode driver that can convert voltage swing into a very small amount of current. We have simulated the proposed signaling circuit using the HSPICE and the proposed signaling circuit has been designed in a 0.25 ${\mu}m$ CMOS technology.

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The development of high brightness IPS mode for LCD Monitors

  • Kang, In-Byeong;Youn, Won-Gyun;Cho, So-Haeng;Song, In-Duk;Ahn, In-Ho;Chung, In-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.11-12
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    • 2000
  • An 18.1" Thin Film Transistor Liquid Crystal Display (TFT LCD) monitor adopting high brightness In Plane Switching (IPS) technology was realized. While conventional IPS structure used a Chromium (Cr) and Molybdenum (Mo) for a drain electrode, Indium Tin Oxide (ITO) was proposed and verified in this paper. Black sticky micropeal spacers were introduced for the reduction of light scattering phenomena, which was observed at dark room with the conventional micropeal spacers. With the proposed method, more than 10 % aperture ratio was increased and the excellent image quality was obtained.

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The Novel OverDriving Technology with Optimum Look-Up-Table

  • Huang, Ming-Wei;Huang, Juin-Ying;Tseng, Wen-Tse;Yu, Hong-Tien
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.276-279
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    • 2005
  • The proposed Novel OverDriving Technology with Optimum Look-up-Table(LUT)is suggested to be a better solution to reducing the occurrence of overshooting caused by the traditional overdriving method implemented to normally liquid crystal (VA mode). Chunghwa Picture Tubes, LTD. (CPT) has successfully implement this tech into 20 inch TFTLCD TV module at the present day. The proposed technology can speed up gray-to-gray response time of LCD less than one half of frame time. On the side, Optimum LUT construction apply the compression scheme to record total actual grayscale transfer characteristics instead of applying the normal spread method such as linear / non-linear interpolation. The memory space is been reduced and the distortion of the image quality is lesser.

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Dual Domain Effect on a Rubbing Mura in a Fringe-Field Switching (FFS) Liquid Crystal Display

  • Oh, S.M.;Jeon, Y.M.;Lee, S.H.;Eom, T.Y.;KIM, H.Y.;LIM, Y.J.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.426-429
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    • 2005
  • The fringe-field switching (FFS) mode associated with a transition from a homogenously aligned to twist deformation require rubbing process. In this devices, $1^o$ of misalignment in an azimuthal direction could cause voltage-dependent transmittance (V-T) to be different from that in a normal area and consequently results in a rubbing mura. According to our studies, the single domain FFS cells are much more sensitive to the rubbing mura than the dual domain FFS cell. Moreover, the FFS cells with negative LC are much more sensitive to the rubbing mura than the FFS cells with positive LC.

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Study on Controlling Pretilt Angle and Electrical Characteristics in ECB cell by Polymerized Reactive Mesogen monomer (ECB 셀에서 UV 경화성 RM 단분자에 의한 선경사각 조절 및 전기적 특성에 관한 연구)

  • Jeon, Eun-Jeong;Kim, Seong-Su;Lim, Young-Jin;Lee, Myoung-Hoon;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.397-398
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    • 2008
  • We have studied the electrically controlled birefringence (ECB) mode using reactive mesogen (RM) monomer to control pretilt angle and improve electrical characteristics. The measure of capacitance confirmed new pretilt angle by RM monomer, and Voltage Holding Ratio (VHR) was increased more than normal ECB cell.

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