• 제목/요약/키워드: Mesogen

검색결과 67건 처리시간 0.028초

Polarization Converting Waveguide Devices Incorporating UV-curable Reactive Mesogen

  • Chu, Woo-Sung;Kim, Sung-Moon;Kim, Jun-Whee;Kim, Kyung-Jo;Oh, Min-Cheol
    • Journal of the Optical Society of Korea
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    • 제15권3호
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    • pp.289-292
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    • 2011
  • Reactive mesogen (RM) is an organic liquid crystal molecule that can be self-aligned to have an optic axis of birefringence when coated over a polyimide alignment film. A free-standing optical wave-plate film consisting of RM and low-loss optical polymers was fabricated in this work, and the film was inserted across the polymer waveguide to form an integrated optical polarization converter. For convenient evaluation of the polarization converters, a waveguide polarizer and analyzer were fabricated in series. The polarization conversion efficiency was measured to be 25 dB for the wavelength range from 1520 to 1580 nm. The wave plate exhibited a temperature-dependent retardation of $4.5^{\circ}$ for a temperature change from 25 to $100^{\circ}C$.

광경화성 단분자를 이용한 PVA모드의 8-도메인 형성방안 연구 (Study on PVA mode using the UV curable reactive mesogen (RM))

  • 김우일;김성민;조인영;김미영;손정호;유재진;김경현;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.339-340
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    • 2008
  • The Conventional PVA (patterned vertical alignment) mode showed characteristics of 8-domain using T-T type or C-C type. But these methods have disadvantages such as decreasing aspect ratio and transmittance. In order to resolve these problems, in this paper we have studied a new 8-domain method which is partially using the UV curable reactive mesogen (RM) that is a role in surface stabilization. The characteristic of off-axis color shift is decreased because the part of surface stabilized area is compensated to other area in a pixel. Consequently, the device shows improved color shift by 8-domain.

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Polarization-Dependent Microlens Array Using Reactive Mesogen Aligned by Top-Down Nanogrooves for Switchable Three-Dimensional Applications

  • Son, Ki-Beom;Kim, Mugeon;Park, Min-Kyu;Kim, Hak-Rin
    • Journal of the Optical Society of Korea
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    • 제19권3호
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    • pp.265-271
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    • 2015
  • We propose a reactive mesogen (RM) lens array to obtain good focusing behavior along with a short focal plane, where the focusing behavior is switchable according to the polarization state of incident light. Polarization-dependent focusing behavior is obtained using a planoconvex RM microlens array on a planoconcave isotropic lens template. Even though the sagitta of our RM lens is high, to obtain the short focal length, the RM layer can be aligned well by introducing a top-down alignment effect, using a nanogrooved template. The optical noise due to the $moir{\acute{e}}$ effect generated by the nanogrooves on the surface of the planoconvex RM layer can be removed simply by overcoating a thin RM layer, which is self-aligned by the geometric surface effect, without an additional alignment process. We demonstrate a hexagonal-packed RM lens array that has a very high fill factor and symmetric phase profile, for an ideal lens.

Synthesis and Liquid Crystalline Properties of the Compounds Consisting of a Schiff Base Type Mesogen and a Dyad Type Aromatic Ester Structure Interconnected Through the Central Hexamethylene Spacer

  • Jung-Il Jin;Hyo-Seok Kim;Jin-Wook Shin;Bong Young Chung;Byung-Wook Jo
    • Bulletin of the Korean Chemical Society
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    • 제11권3호
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    • pp.209-214
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    • 1990
  • A series of compounds consisting of 4'-oxybenzylidene-4-n-butylaniline, a mesogen, and a p-substituted phenoxyterephthaloyl structure a non-mesogen, interconnected through a central hexamethylene spacer were synthesized and their thermal behavior and liquid crystallinity were studied. p-Substituents included in this study are H, Cl, CN, $NO_2,\;n-C_4H_9O$ and phenyl groups. The compounds having phenyl and $n-C_4H_9O$ substituents are enantiotropic and form smectic-A(SA) and nematic (N) phases. The compound with $NO_2$ substituent is monotropic and forms only a nematic phase on heating the solid, whereas it forms nematic as well as $S_A$ phases on cooling the isotropic liquid. The rest compounds were found to be non-liquid crystalline. This is in great contrast to the fact that the monomesogenic model compound 4'-n-hexyloxybenzylidine-4-n-butylaniline forms $S_B,\;S_C,\;S_A$ and N phases enantiotropically.

광 경화성 단분자를 이용한 수직 배향 액정 표시 소자의 노광 조건에 따른 표면 안정화의 연구

  • 김혜영;김대현;권동원;김우일;조인영;김성민;이승희;정연학;류재진
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.187-187
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    • 2009
  • The PVA(patterned vertical alignment) mode has a excellent dark state at normal direction. but they has a disclination area at divided domain region at voltage on state. so this disclination make a slow response time and decrease transmittance. To overcome this problem, we research about polymer stabilized vertical alignment (PS-VA) method which was using the UV curable reactive mesogen. According to our research, UV exposure condition which was UV dosage condition effected to rising time and decay time and also threshold voltage.

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

  • 권동원;전은정;임영진;이명훈;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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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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광경화성 단분자를 이용한 pattern free vertical alignment 모드의 전기 광학 특성 연구 (Study on electro optic characteristic of pattern free vertical alignment (PFVA) mode using the uv curable reactive mesogen (RM))

  • 조인영;황성진;김성민;황지혜;이승희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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    • pp.45-46
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    • 2008
  • The conventional biased vertical alignment (BVA) mode has several advantages such as rubbing- and protrusion-free, wide-viewing angle and stable LC dynamics against external pressure. However manufacturing process of BVA mode is difficult task because the pixel and bias electrode signal are different in each frame. To solve this problem, we investigated the pattern free vertical alignment (PFVA) by using the UV-curable reactive mesogen (RM), in which the LC molecules were made to be pre-tilted. Eventually transmittance and response time in PFVA mode were found to be improved as compared to BVA mode.

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Progress of Study on Mesogen-Jacketed Liquid Crystalline Polymers at Peking University

  • Fan, Xing-He;Chen, Xiao-Fang;Wan, Xin-Hua;Chen, Er-Qiang;Zhou, Qi-Feng
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.90-90
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    • 2006
  • Mesogen-Jacketed Liquid Crystalline Polymers, MJLCPs, are polymers with mesogenic side groups directly attached to main-chains without using flexible connecting spacers and are able to form liquid crystalline structures. Later work on structure-property of the polymers revealed that the side groups are not necessarily mesogenic for the polymers to form a mesophase so long as that the side groups are directly attached to the backbones and the side groups are large enough. Because of its inherent chain stiffness and that the monomers of MJLCPs are readily polymerizable by "living" free radical polymerizations, MJLCP offered a unique handy tool for making block copolymers. In addition, MJLCP offered also new opportunities for novel functional materials.

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Chiral Mesophase Derived from Achiral Polymers with Banana-Shaped Mesogens and Their Model Compounds

  • Choi, E-Joon;Kim, Eun-Chul;Kwon, Myung-Hun;Zin, Wang-Cheol;Kim, Young-Chul;Paek, Sang-Hyon
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.242-243
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    • 2006
  • In this work, we report the synthesis and characterization of azomethineester polymers that consist of banana-shaped mesogen in their backbone. Two parts of the key structure of five-ring bent-core mesogen were modified by connecting different angle of central unit (Ar), and introducing lateral substituent into the outer ring (X). The synthetic details includes (1) placing the dioxydodecamethylene unit as a flexible spacer, (2) possessing 2,3- or 2,7-naphthylene, or 1,2-phenylene connection on the central unit, and (3) introducing fluorine or chlorine substituent (X = F or Cl) into the outer phenylene unit.

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