• Title/Summary/Keyword: liquid-crystal-display (LCD)

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Technique of measuring optic axis off-alignment error for LCD polarizing and compensating plates by using a polarimetry (편광법을 이용한 LCD 편광판과 보상판의 광축 정렬오차 측정)

  • An Sung Hyuck;Kim Sang Jun;Kim Sang Youl
    • Korean Journal of Optics and Photonics
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    • v.15 no.6
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    • pp.527-530
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    • 2004
  • Using a polarimetry based on the rotating analyzer ellipsometer, a technique of measuring off-alignment angle between the slow-axis of the LCD (Liquid Crystal Display) polarizing plate and the transmission axis of the compensating plate attached to the polarizing plate is proposed. It is anticipated that this technique will reduce the optic axis off-alignment error coming from the process of attaching the compensating plate to the LCD polarizing plate markedly, and therefore will help maintain the quality of LCD display image uniformly.

Viewing Angle Controllable LCD by Thermal Modulation of Optical Layer

  • Han, In-Young;Gwag, Jin-Seog;Lee, You-Jin;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.348-351
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    • 2008
  • We suggest a viewing angle control mode of liquid crystal display(LCD) with additive thermal controllable optical layer [TCOL], which composed of homeotropically or homogenously well aligned LC layer and patterned hating lines on a substrate. In this system, LCD modes with wide viewing angle characteristics can be used as a main panel.

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A Transflective Liquid Crystal Display Driven by the Fringe Field Using a Liquid Crystal with a Negative Dielectric Anisotropy

  • Kim, Jin-Ho;Her, Jung-Hwa;Lim, Young-Jin;Kumar, Pankaj;Lee, Seung-Hee;Park, Kyoung-Ho;Lee, Joun-Ho;Kim, Byeong-Koo
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.3
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    • pp.134-137
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    • 2010
  • We have proposed a transflective liquid crystal display (LCD) driven by the fringe field using a liquid crystal (LC) with a negative dielectric anisotropy. The device used different twist angles of the liquid crystals (LC) in the transmissive (T) and the reflective (R) regions when voltage is applied. With the optimization of the pixel electrode width and the distance between them, the LC directors in the R- and T-regions can be rotated by about $22.5^{\circ}$ and $45^{\circ}$ on an average, respectively. As a result, a high image quality transflective LCD with a single gap, a single gamma, and a wide viewing angle characteristics in both the R- and T- regions can be realized.

Electro-Optical Characteristics of Plastic STN Cell using photoalignment method (광배향을 이용한 플렉시블 STN 셀의 전기 광학 특성)

  • Bae, Yu-Han;Hwang, Jeoung-Yeon;Kim, Jong-Hwan;Nam, Ki-Hyung;Lee, Whee-Won;Kim, Kang-Woo;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.1007-1009
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    • 2004
  • We investigated the electro-optical(EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface with polymer film using rubbing and photoalignment method. Monodomain alignment of the plastic STN-LCD can be observed. A faster response time for the photoaligned plastic STN-LCD on the polyimide(PI) surfaces can be achieved than rubbingaligned plastic STN-LCD.

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Electro-Optical Characteristics of Plastic STN Cell using Low Temperature Process (저온 공정을 이용한 플라스틱 STN 셀의 전기 광학 특성)

  • Kim, Kang-Woo;Hwang, Jeoung-Yeon;Kim, Jong-Hwan;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05a
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    • pp.202-205
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    • 2004
  • We investigated the electro-optical(EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface using polymer film. The NLC pretilt angles generated are about $18^{\circ}$ by the rubbing alignment method on thin plastic substrates. However, the pretilt angle are at about $13^{\circ}$ lower on the glass substrate than on thin plastic substrate. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance(V-T) curve of the plastic STN-LCD was observed on the polyimide(PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide(PI) surfaces using polymer film can be achieved.

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Fringe-Field Switching Transflective Displays

  • Lim, Y.J.;Choi, M.O.;Lee, S.H.;Song, J.H.;Jeong, Y.H.;Kim, H.Y.;Kim, S.Y.;Lim, Y.J.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.419-422
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    • 2005
  • We have studied transflective liquid crystal displays (LCDs) associated with fringe-field switching (FFS) mode to achieve high image quality. In the past, several cell structures were used to fabricate transflective FFS liquid crystal display s. Their structures and characteristics are carefully examined to find their merits and cons. Further, optimization of cell parameters to achieve a single driving circuit is performed.

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A New Transflective Geometry of Low Twisted Nematic Liquid Crystal Display having a Single Cell Gap

  • Kim, Jin-Yool;Kim, Dong-Woo;Yu, Chang-Jae;Lee, Sin-Doo
    • Journal of Information Display
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    • v.5 no.3
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    • pp.14-17
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    • 2004
  • We have developed a new type of transflective liquid crystal display (LCD) with a single cell gap and a single LC mode. In our transflective configuration, a single LC mode of a 60$^{\circ}$ twisted nematic LC was used for both transmissive and reflective applications. The measured electro-optic characteristics of our transflective LC cell agree well with numerical simulation results. Moreover, the transmittance was found to show similar behavior to the reflectance.

An integrated design approach for Light Guide Panel(LGP) of Back Light Unit(BLU) to improve the Optical Performance of Liquid Crystal Display(LCD) (LCD 제품의 광학 성능 향상을 위한 백라이트 유닛용 도광판의 최적설계)

  • Lee, Gab-Seong;Jeong, Jae-Ho;Yoon, Sang-Joon;Choi, Dong-Hoon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1048-1052
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    • 2008
  • Difficulties in developing process of Liquid Crystal Display(LCD) products such as frequent design modifications, various design requirements, and short-term development period bring on the need of integrated design approach that is efficient and easy to handle. Back Light Unit(BLU) of the LCD, which drastically affects the optical performance of LCD products, is divided into in-coupling part and out-coupling part. Serration of the in-coupling part flattens the light received from point light sources and dot pattern of the out-coupling part regularizes the light sent to screen. Therefore, the optical performance of a LCD product is largely influenced by the shape of serration and the arrangement of dot pattern. In this research, a new design approach which enables to improve the optical performance of LCD products and overcome the prementioned difficulties in developing process of LCD products is proposed. The shape of serration is parameterized to 3 parameters and out-coupling part is partitioned into 10 partitions to apply the optimization technique to this problem. 3 parameters for the shape of serration and densities of 10 partitions are used as design variables in the design optimization. Optical simulation tool named SPEOS is used to evaluate the optical performance of the LCD product. Since the optical simulation uses the random ray tracing technique, numerical noise may possibly be included in the simulation process. To solve the problem caused by numerical noise, the PQRSM which can stably find the solution of the noise problem is used in this research.

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

  • Kimura, Munehiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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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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