• Title/Summary/Keyword: Liquid crystal

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Dual Frequency Switchable Flexoelectric Cholesteric Devices

  • Chien, Liang-Chy;Shi, Lei
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.105-108
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    • 2005
  • We demonstrate an electro-optical device based on the flexoelectric effect of a short-pitched cholesteric liquid crystal. By using a dual-frequency switchable nematic, a small amount of chiral dopant and a small amount of phase-separated polymer localized on the surface, we were able to create a device that operates in amplitude (flexoelectric) and phase(dielectric) modes. At high frequency the dual frequency liquid crystal suppresses the phase mode at higher voltage, which improves the switching speed, and thereby preserving the in-plane-switching mode.

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Polarizer-free Liquid Crystal Devices

  • Lin, Yi-Hsin;Ren, Hongwen;Wu, Yung-Hsun;Wu, Shin-Tson
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.980-981
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    • 2007
  • Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. They usually require two polarizers; therefore the optical efficiency is limited. We introduce two general principles of polarization-free liquid crystal devices and also show several LC devices by applying the principles.

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New Techniques for Fabrication of Flexible Plastic LCD's

  • West, John.L.;Novotny, Grea R.;Fisch, Michael R.;Heinman, David
    • Journal of Information Display
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    • v.2 no.4
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    • pp.15-18
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    • 2001
  • We report simple techniques to manufacture low-powered, high-resolution, reflective cholesteric displays using flexible plastic substrates. We use wax transfer printing to replace photo-lithography and incorporate polymer walls to increase the mechanical strength and lifetime of the displays. These printing methods can easily be adapted to roll-to-roll production.

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Scanning Electrode Driver IC Development for TFT Matrix-Type Liquid Crystal Panel (TFT Matrix형 액정판넬의 주사전극 구동 IC 개발)

  • 이화이;정교영;변상기;유영갑
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.9
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    • pp.27-36
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    • 1992
  • A design of scanning electrode driving IC chip has been implemented aiming at the application to liquid crystal color television displays. The chip reflects the design characteristics of high quality liquid crystal panels and satisfies specifications of NTSC type color television displays. The design was verified using logic and circuit simulation, and fabricated using a high voltage CMOS process. A fully working die has been obtained that can be readily applicable to commercial color liquid crystal panels.

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Image Sticking Property in the In-Plane Switching Liquid Crystal Display by Residual DC Voltage Measurements

  • Jeon, Yong-Je;Seo, Dae-Shik;Kim, Jae-Hyung;Kim, Hyang-Yul
    • KIEE International Transactions on Electrophysics and Applications
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    • v.11C no.4
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    • pp.142-145
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    • 2001
  • The residual DC phenomena in the in-plane switching(IPS)-liquid crystal display(LCD) by the voltage-transmittance (V-T) and capacitance-voltage (C-V) hysteresis method on rubbed polyimide (PI) surfaces were studied. We found that the residual DC voltage in the IPS-LCD was decreasing with the increasing concentration of cyano LCs. The residual DC voltage of the IPS-LCD can be improved by the high polarity of cyano LCs.

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RHEOLOGICAL PROPERTIES OF OIL/WATER EMULSION AND OIL/LIQUID CRYSTAL/WATER SYSTEMS AND THEIR CONSUMER PERCEPTION IN HAIR CARE PRODUCTS

  • Kim, Chong-Youp;Hong, Jong-Eoun;Kim, Su-Hyun;Kang, Hak-Hee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.25 no.4 s.34
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    • pp.123-131
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    • 1999
  • Liquid crystal known as a rheological barrier to coalescence of oil droplets, increases emulsion stability, water-holding capacity and promotes active material penetration to skin. Some investigation for its rheological characteristics have been reported but its relations to consumer perception have been rarely published. In this study, oil/water emulsion and oil/liquid crystal/water systems were manufactured using the same composition or Behenyltrimethylammonium chloride/Cetostearyl alcohol/Lanolin oil. and rheological properties or each system were investigated with Cone and Plate rheometer. The formation of liquid crystalline phase was observed with polarized microscope and Differential Scanning Calorimeter. Continuous shear experiment, creep, yield and water holding capacity were measured for oil/water and oil/liquid crystal/water systems. The results were compared with sensory evaluations. Oil/liquid crystal/water system showed higher,viscosity at the same shear rate. higher viscoelasticity and higher yield stress than oil/water system. These properties were expected to show good spreadability and excellent richness without waxiness in hair can: products of creme type. This expectation was consistent with the results of sensory experiments. Water-holding capacity was evaluated by measuring residual water of specimens at specific temperature and relative humidity. Oil/liquid crystal/water system was proved to have higher ability to hold water in comparison with oil/water system. The results indicated that oil/liquid crystal/water system was of benefit to rheological properties creme type hair care products.

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PHEOLOGICAL PROPERTIES OF OIL/WATER EMULSION AND OIL/LIQUID CRYSTAL/WATER SYSTEMS AND THEIR CONSUMER PERCEPTION IN HAIR CARE PRODUCTS

  • Kim, Chongyoup;Jongeoun Hong;Kim, Suhyun;Hakhee Kang
    • Proceedings of the SCSK Conference
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    • 1999.10a
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    • pp.123-131
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    • 1999
  • Liquid crystal known as a rheological barrier to coaleseence of oil dorplets. increases. emulsion stability, water-holding capacity and promotes active material penetration to skin. Some investigation for its rheological characteristics have been reported but its relations to consumer perception have been rarely published. In this study oil/water emulsion and oil/liquid crystal/water systems were manufactured using the same composition of Behenyltrimethylammonium chloride/Cetostearyl alcohol/Lanolin oil. and rheological properties of each system were investigated with Cone and Plate rheometer. The formation of liquid crystalline phase was observed with polarized microscope and Differential Scanning Calorimeter. Continuous shear experiment, creep yield and water holding capacity were measured for oil/water and oil/liquid crystal/water systems. The results were compared with sensory evaluations. Oil/liquid crystal/water system showed higher viscosity at the same shear rate, higher viscoelasticity and higher yield stress than oil/water system. These properties were expected to show good spreadability and excellent richness without waxiness I hair care products of creme type. This expectation was consistent with the results of sensory experiments. Water-holding capacity was evaluated by measuring residual water of specimens at specific temperature and relative humidity, Oil/liquid crystal/water system was proved to have ability to hold water in comparison with oil/water system. The results indicated that oil/liquid crystal/water system was of benefit to rheological properties creme type hair care products.

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Heat Transfer on a Heated Flat Plate by an Impinging Round Jet Using Liquid Crystal (Liquid Crystal을 이용한 원형충돌분류의 전열특성 연구)

  • 오승묵;이상준
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1566-1574
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    • 1992
  • Local heat transfer characteristics for a round air jet impinging normally on a heated flat plate were experimentally investigated. The problem parameters investigated were jet Reynolds number, Re=4000,10000, and 20000, and nozzle-to-plate spacing(L/D) of 2,6, and 10. The temperature variations on the flat uniform heat flux surface were mapped using a thermo-sensitive liquid crytal sheet. The isochromatic images corresponding to the characteristic temperature of liquid crystal were analyzed with the help of a digital image processing system. The local Nusselt number, Nu decreased rapidly in the impingement region and exhibited a similar profiles in the wall jet region independent of the nozzle-to-plate spacing L/D. In the case of large Reynolds number, heat transfer rate (Nu) was proportional to 0.5 power of the Reynolds number. For L/D=2, a secondary peak in the heat transfer rate was seen in the region of X/D=1.5~3 due to the transition from laminar to turbulent boundary layer.

Development and Evaluation of Non-Hydrous Skin Analogue Liquid Crystal using Thermo-Sensitivity Smart Sensor

  • Yoo, Kwang-Ho;Hong, Jae-Hwa;Eun, So-Hee;Jeong, Tae-Hwa;Jeong, Kwan-Young
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.3
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    • pp.367-374
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    • 2014
  • In this study, skin permeation enhancement was confirmed by designing it to have a structure and composition similarity to the intercellular lipids that improve miscibility with skin by cross-linked lipids poloxamer. The cross-linked lipids poloxamer was synthesized and analyzed by 1H NMR that structure dose had conjugated pluronic with ceramide3. Active component is released by modification of liquid crystal structure because PPO part, large-scale molecule block of pluronic, has hydrophobic nature at skin temperature of $35^{\circ}C$. Conjugated pluronic with ceramide3 was synthesized using Pluronic F127 and p-NPC (4-nitrophenyl chloroformate) at room temperature yielded 89%. Pluronic(Ceramide 3-conjugated Pluronic) was synthesized by reaction of p-NP-Pluronic with Ceramide3 and DMAP. The yield was 51%. This cross-linked lipids poloxamer was blended and dissolved at isotropic state with skin surface lipids, phospholipid, ceramide, cholesterol and anhydrous additive solvent. Next step was preceded by ${\alpha}$-Transition at low temperature for making the structure of Meso-Phase Lamella, and non-hydrous skin analogue liquid crystal using thermo-sensitivity smart sensor, lamellar liquid crystal structure through aging time. For confirmation of conjugation thermo-sensitivity smart sensor and non-hydrous skin analogue liquid crystal, structural observation and stability test were performed using XRD(Xray Diffraction), DSC(Differential Scanning Calorimetry), PM (Polarized Microscope) And C-SEM (Cryo-Scanning Electron Microscope). Thermo-sensitivity observation by Franz cell revealed that synthesized smart sensor shown skin permeation effect over 75% than normal liquid crystal. Furthermore, normal non-hydrous skin analogue liquid crystal that not applied smart sensor shown similar results below $35^{\circ}C$ of skin temperature, but its effects has increased more than 30% above $35^{\circ}C$.

Molecular orientational surface structures of polymers for liquid crystal alignment

  • Ohe, Masahito
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.611-614
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    • 2006
  • Sum-frequency vibrational spectroscopy (SFVS) has been used to study the molecular orientations at the polymer surfaces for liquid crystal alignment. Various molecular orientations appear at the surface depending on various types of surface treatments and polymers.

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