• Title/Summary/Keyword: Ferroelectric liquid crystal

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반사형 강유전성 액정 공간 광 변조기를 이용한 CGH의 양자화 방법에 따른 재생 특성 비교

  • 최한섭
    • Korean Journal of Optics and Photonics
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    • v.10 no.1
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    • pp.32-39
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    • 1999
  • In this paper, we made CGH patterns that had continuous amplitude distribution binary coded patterns with two different methods, and analyzed those patterns by using LCSLM (liquid crystal spatial light modulator). The error diffusion algorithm and direct quantization method were used as the binarization methods. The parameters of overall average brightness, mean square error, and diffraction efficiency were used in the comparison of reconstruction characteristics. The LCSLM which we used in this experiment was a binary reflective ferroelectric liquid crystal spatial light modulator addressed electrically with 256$\times$256 pixels, 87% fill factor and 15$\mu$m pixel pitch.

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The Microstructure and Ferroelectric Properties of Ce-Doped Bi4Ti3O12 Thin Films Fabricated by Liquid Delivery MOCVD

  • Park, Won-Tae;Kang, Dong-Kyun;Kim, Byong-Ho
    • Journal of the Korean Ceramic Society
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    • v.44 no.8
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    • pp.403-406
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    • 2007
  • Ferroelectric Ce-doped $Bi_4Ti_3O_{12}$ (BCT) thin films were deposited by liquid delivery metal organic chemical vapor deposition (MOCVD) onto a $Pt(111)/Ti/SiO_2/Si(100)$ substrate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface, and the cross-section morphology of the deposited ferroelectric flims. After annealing above $640^{\circ}C$, the BCT films exhibited a polycrystalline structure with preferred (001) and (117) orientations. The BCT lam capacitor with a top Pt electrode showed a large remnant polarization ($2P_r$) of $44.56{\mu}C/cm^2$ at an applied voltage of 5 V and exhibited fatigue-free behavior up to $1.0{\times}10^{11}$ switching cycles at a frequency of 1 MHz. This study clearly reveals that BCT thin film has potential for application in non-volatile ferroelectric random access memories and dynamic random access memories.

Time-Multiplexed 3D Display

  • Travis, Adrian R. L.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.444-447
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    • 2003
  • A flat panel field sequential 3D display can be made by illuminating a ferroelectric liquid crystal display with scanning illumination passed through a transparent slab embossed with a grating. The concept is expected to enable wide fields of view, sharp discrimination between views, little blurring at depth, and no repetition of views.

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Synthesis of Ferroelectric Liquid Crystals Obtained from Optically Active l-isoleusine (광학활성 이소로이신을 출발물질로 한 강유전성 액정물질의 합성)

  • Jeong, N.H.;Kikuchi, H.;Kajiyama, T.
    • Journal of the Korean Applied Science and Technology
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    • v.13 no.3
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    • pp.51-60
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    • 1996
  • A new one series of chiral schiff's base containing benzylidene aniline moieties was synthesized and characterized by IR, $^1H$ NMR. elementary analysis, and polarized optical microscopy(POM). The yield of these synthetic compounds was in the range of $62{\sim}67^{\circ}C$. The results showed that most of the synthetic compounds were monotropic liquid crystal and exhibited chiral smectic C($Sc^{\ast}$) liquid crystal phases, and the range of phase transition temperature was to $71.4^{\circ}C$ from $45.0^{\circ}C$.

Time-Resolved Infrared Spectroscopy of Molecular Reorientation During FLC Electro-Optic Switching

  • Jang, Won-Gun;Clark, Noel A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1112-1117
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    • 2003
  • Polarized Fourier transform infrared (IR) absorption is used to probe molecular conformation in a ferroelectric liquid crystal (FLC) during the reorientation induced by the external field. Spectra of planar aligned cells of FLC W314 are measured as functions of IR polarizer orientation and electric field applied to the FLC. The time evolution of the dichroism of the absorbance due to biphenyl core and alkyl tail molecular vibration modes, is observed. Static IR dichroism experiments show a W314 dichroism structure in which the principal axis of dielectric tensor from molecular core vibration are tilted further from the smectic layer normal than those of the tail. This structure indicates the effective binding site in which the molecules are confined in the Sm-C phase has, on average, "zig-zag" shape and this zig-zag binding site structure is rigidly maintained while the molecular axis rotates about the layer normal during field-induced switching.

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Studies of Molecular Orientation for Ferrielectric Liquid Crystal by Phase Transitions

  • Kim, S.W.;Choi, H.;Song, J.H.;KIm, J.H.;Kumar, S.;Choi, J.W.;Kim, Y.B.;Shin, S.T.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.61-62
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    • 2000
  • We have studied the molecular orientation by the phase transitions of the chiral smectic liquid crystals, 4-(1-Trifluoromethyl-6-ethoxy-hexyloxycarbonlphenyl)-4-nonyloxybiphenyl-4-carbo-xylate (R-TFMEOHPNBC) to seek the original solution of the zig-zag defect using two different experimental techniques; optical system and x-ray scattering. The phase sequence is gamma ferroelectric $(SmC{\gamma}\;^*)$ ${\rightarrow}$ smectic A (SmA) ${\rightarrow}$ isotropic (I). Existence of two layer spacing at chiral smectic phase gives a possibility of the molecular orientation in two different tilt angles, ${\theta}\;_1$ and ${\theta}\;_2$, which are separated each other to the layer normal at a given temperature. The gamma ferroelectric-like phase is, first, discovered in the single compound.

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Optically Addressed Spatial Light Modulators Using Smectic $C^*$ Liquid Crystal and Intrinsic Hydrogenerated Amorphous Silicon

  • ;;Niel Ceilings
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.02a
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    • pp.298-299
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    • 2000
  • 3차원 영상을 디스플레이하기 위한 반사형 광기록식 공간 광소자(Optically Addressed Spatial Light Modulator)를 연구하였다. 다시점 영상으로 표현되는 3차원 영상을 시분할 방식으로 디스플레이 하기 위해서는 고속의 프레임 구동이 가능한 디스플레이 소자가 있어야 하는데 본 연구에서는 Surface Stabilized Ferroelectric Liquid Crystal을 이용하여 그림 1과 같은 구조를 갖는 소자를 제작하였다.$^{(1)}$ 입력상이 입사되는 방향에 1.1 미리 미터 정도의 ITO 유리 기판이 있으며 투명 전극 다음에 약 2마이크론 정도의 비결정질 구조를 갖는 Si:H 감광층이 있다. 반사형 구조를 위해서 반사경으로 알루미늄 층을 10마이크론 X 10 마이크론 크기의 미소 패턴으로 화소화하였으며 강유전성 액정 결정을 Surface Stabilized화하기 위해서 배양막과 2 마이크론 이하의 Spacer를 두었다. 일반적인 액정 소자와 같이 다시 배양막과 유리 기판을 갖게 하였다. (중략)

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