• Title/Summary/Keyword: Optically compensated splay

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Electro-optic Characteristics of Reflective Optically Compensated Splay Cell (반사형 Optically Compensated Splay 셀의 전기-광학 특성)

  • 송제훈;오상민;이종문;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.9
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    • pp.983-987
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    • 2004
  • We have studied electro-optic characteristics of reflective optically compensated splay (R-OCS) cell. The initial configuration of this cell is in splay form such that a mid director lies parallel to the substrate and around it hybrid structure is formed symmetrically so the optically compensation effect exists. Optimized optical configurations could be achieved by using a single polarizer, a quarter-wave film and a cell with quarter-wane retardation. The optimal cell retardation is 0.34 ${\mu}$m, allowing to have large cell gap. The cell provides high contrast ratio of 80:1 at normal direction and the region with contrast ratio over 5:1 covert up to 160$^{\circ}$ horizontally and vertically at all wavelength range.

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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A Novel LC Device Associated with Optically Compensated Splay Structure (광학적 자기 보상 스플레이 구조를 갖는 새로운 액정 소자)

  • 김승재;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.536-540
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    • 2004
  • A novel nematic liquid crystal (LC) cell with splay structure exhibiting wide viewing angle, fast response time and high transmittance at the same time has been developed. With rubbed homeotropic alignment in parallel directions, the device shows bend alignment in the absence of vertical electric field. However, with applied high voltage in a pulse form, the LC shows a optically compensated splay (OCS) orientation such that the mid-director is parallel to a substrate and at both surfaces the LCs are aligned vertically in parallel direction. In the device, the birefringence of the cell becomes tunable with applying voltage, i.e., the amount of light passed through the cell can be controlled by controlling the orientation of the LC. Since the OCS cell has a self-compensation structure such that the LC has a mirror symmetry along the mid-director, the device shows a wide viewing angle with only a single domain and a fast response time.

Liquid Crystal Device Associated with Fringe-field Driven Vertically Aligned Optically Compensated Splay (OCS) (프린지 필드에 의해 구동되는 수직 배향된 광학적 자기 보상 스플레이 액정 소자)

  • Jung, B.S.;Kim, S.J.;Oh, S.M.;Kim, H.Y.;Lee, S.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05a
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    • pp.157-160
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    • 2004
  • We have studied an optically compensated splay (OCS) mode driven by fringe electric field. The OCS LC configuration obtained by applying voltage to vertically aligned LCs shows a dark state when an optic axis of the OCS cell coincides with one of crossed polarizer axis. When the fringe electric field is applied, the LC director rotates in plane above whole electrode surface, giving rise to high transmittance and wide viewing angle simultaneously.

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Study on Phase Transition and Response Time of Optically Compensated Splay Cell according to Pretilt Angle (선경사각에 따른 광학적 자기보상 스플레이 셀의 상전이와 응답속도 연구)

  • Hwang, Seong-Han;Jung, Byoung-Sun;Hwang, Jeoung-Yeon;Seo, Dae-Shik;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.422-423
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    • 2006
  • We have studied phase transition time and response time of optically compensated splay(OCS) cell as a function of surface pretilt angle. With decreasing surface pretilt angle, phase transition time decreases and response time becomes faster in the OCS cell. Besides, the more surface pretilt angle decreases, the easier OCS structure is obtained.

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Study on Electro-optical Characteristics in the Optically Compensated Splay Cell using Polymer Surface Alignment (고분자 표면 배향을 이용한 광학 보상 퍼짐 셀의 특성 향상 연구)

  • Kim, Seong-Su;Hwang, Seong-Jin;Hwang, Seong-Han;Lee, Myong-Hoon;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.424-425
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    • 2007
  • We have studied the optically compensated splay mode using reactive mesogen (RM) monomer to reduce setting voltage and phase transition time from initial bend to splay state. When the OCS cell has low pretilt angle close to $45^{\circ}C$, OCS state can be formed easily. The low pretilt angle was formed through the polymerization of UV curable reactive RM monomer at the surfaces. In this way, reorientation of the LC is well defined and thus the device shows better performances in setting voltage and phase transition time.

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UV 경화성 단분자를 이용한 광학 보상 퍼짐 셀의 전기적 특성 향상 연구

  • Gwon, Dong-Won;Jeon, Eun-Jeong;Im, Yeong-Jin;Lee, Myeong-Hun;Lee, Seung-Hui
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.188-188
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    • 2009
  • We have studied the optically compensated splay (OCS) mode using reactive mesogen (RM) monomer to reduce critical voltage, setting voltage and phase transition time from initial bend to splay state. Through the polymerization of UV curable RM monomer, the high pretilt angle from vertical alignment was formed at the surfaces. In this way, orientation of the LC with OCS mode can be achieved without setting voltage and improved electric characteristic.

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Liquid Crystal Device associated with Fringe-Field Driven Optically Compensated Splay

  • Jung, B.S.;Kim, S.J.;Oh, S.M.;Lee, S.H.;Kim, H.Y.;Kim, S.Y.;Lim, Y.J.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1197-1199
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    • 2004
  • We have studied an optically compensated splay (OCS) mode driven by fringe electric field. The OCS configuration obtained by applying voltage to vertically aligned LCs shows a dark state when an optic axis of the OCS cell coincides with one of crossed polarizer axis. When the fringe electric field is applied, the LC director rotates in plane above whole electrode surface, giving rise to the high transmittance, the low operating voltage and wide viewing angle simultaneously.

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A Novel Phase Transition from a Vertical Alignment to Optically Compensated Splay

  • Kim, S.J.;Shin, S.S.;Kim, H.Y.;Hong, S.H.;Lim, Y.J.;Lee, S.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.512-515
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    • 2003
  • We have studied a novel vertical alignment liquid crystal cell. At initial state of a cell with rubbed parallel on top and bottom substrates, the vertically aligned LCs are twisted by $180^{\circ}$. However, after a critical voltage is applied to the cell, the configuration of the LC changes to optically compensated splay form, where the mid-director lies parallel to the substrate and thus the LC has two hybrid alignments around center.

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Realization of Optically Compensated Bend State using Surface Polymer Stabilization

  • Jeon, E.J.;Kang, B.G.;Kwon, D.W.;Lim, Y.J.;Lee, M.H.;Lee, S.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.657-660
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    • 2009
  • Optically compensated bend (OCB) mode has intrinsic characteristics such as wide viewing angle and fast response time. However, in order to operate the OCB mode in bend state, this device needs quick transitions from the initial splay state to bend state. In this paper, we proposed OCB mode with initially bend state using reactive mesogen (RM) monomer for surface polymer stabilization. The device shows continuous reorientation of the LC with applied field and a very fast response time.

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