• Title/Summary/Keyword: Liquid crystal

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Enhanced Electro-optical Characteristics of Liquid Crystal Shutter with a Dual Frequency Liquid Crystal Material (이중 주파수 액정을 적용한 액정 셔터의 고속 응답 특성)

  • Kim, Dae Soo;Han, Seung Hwan;Bae, Geon;Jhun, Chul Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.5
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    • pp.303-306
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    • 2014
  • In this paper, by using a dual frequency liquid crystal material, we propose a liquid crystal device with a fast response characteristics. The dual frequency liquid crystal material has a positive dielectric anisotropy value at a low frequency. With a high frequency, the dielectric anisotropy becomes negative. Therefore, the relaxation process is governed by not only the elastic deformation, but also the dielectric interaction. The measured decay time and rise time were 0.88 ms and 0.33 ms, respectively.

Modeling an e-Beam Addressed Liquid Crystal Projection Display

  • Yang, Deng-Ke;Zhou, Fushan;Molitor, R.J.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.930-932
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    • 2002
  • We have carried a theoretical study on e-beam addressed liquid crystal projection display in which the liquid crystal is switched by the electric field of the charge, produced by an electron beam, on the surface of the display. We calculated the electric field produced by the surface charge, the liquid crystal director configuration and the profile of the transmitted light. We studied the factors affecting the resolution of the display. We also studied the effect of pretilt angle on the performance of the display. The e-beam addressed liquid crystal projection display potentially has the advantages of high resolution and high brightness.

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Fabrication and electro optical properties of stressed liquid crystal cell

  • Lee, Jung-Min;Park, Jin-Seol;Kang, Dae-Seung
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.681-682
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    • 2009
  • We fabricated a stressed liquid crystal cell by mixing liquid crystal with a photo-polymer. By carefully choosing the mixing ratio between liquid crystal and the polymer, and by suitable mechanical shearing of the substrates, we demonstrated feasible electro optical properties for displays.

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Liquid crystal alignment on the inkjet printed polyimide by using new alignment method

  • Hwang, J.Y.;Wonderly, H.;Chien, L.C.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.506-508
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    • 2007
  • We studied the nematic liquid crystal (NLC) alignment capability with a new alignment method utilizing an inkjet printed polyimide (PI) layer. A good, uniform LC alignment was achieved by the good PI printing using a new alignment method. The pretilt angle generated on the printed PI layer using the alignment method was almost the same as that on printed PI layer using rubbing alignment method. In addition, the good electro-optical performances of the new aligned twisted nematic (TN) cell with printed PI surface was obtained

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Effect on Formation of Liquid Crystal Pitch (액정핏치 형성에 관한연구)

  • Gwon, Yeong-Bae;Ryu, Hae-Il
    • 한국기계연구소 소보
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    • pp.15-25
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    • 1984
  • The infrared spectra were determined to discover the characteristics and properties of poff-, PV-, and cc-samples, and studied influence on the formation of mesophase or liquid crystal. The experimental results were as follows; a) Samples with long aliphatic side chain appear cracking texture on temperature forming liquid crystal. b) The fine isotropic microstructure appears in a heterogeneous material containing sulfur, 7.18 w%. c) In the size of molecular weight the lighter than 500 form liquid crystal. d) When poff-sample was treated at $400^{\circ}C$ aliphatic hydrocabon compounds decrease, presented well-oriented bulk liquid crystal.

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Wavelength Divided Trans-reflective Liquid crystal Displays

  • Yang, D.K.;Zhou, F.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.309-310
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    • 2003
  • We have designed novel transreflective liquid crystal displays which utilize dielectric mirrors. The reflective and transmissive modes are operated in different wavelength regions. The displays have the advantages: (1) the brightness as a function of applied voltage is the same for both modes, (2) the backlight and ambient light are utilized efficiently.

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Mechanism of Formation of Three Dimensional Structures of Particles in a Liquid Crystal

  • West, John L.;Zhang, Ke;Liao, Guangxun;Reznikov, Yuri;Andrienko, Denis;Glushchenko, Anatoliy V.
    • Journal of Information Display
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    • v.3 no.3
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    • pp.17-23
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    • 2002
  • In this work we report methods of formation of three-dimensional structures of particles in a liquid crystal host. We found that, under the appropriate conditions, the particles are captured and dragged by the moving isotropic/nematic front during the phase transition process. This movement of the particles can be enhanced significantly or suppressed drastically with the influence of an electric field and/or with changing the conditions of the phase transition, such as the rate of cooling. As a result, a wide variety of particle structures can be obtained ranging from a fine-grained cellular structure to stripes of varying periods to a course-grained "root" structures. Changing the properties of the materials, such as the size and density of the particles and the surface anchoring of the liquid crystal at the particle surface, can also be used to control the morphology of the three-dimensional particle network and adjust the physical properties of the resulting dispersions. These particle structures may be used to affect the performance of LCD's much as polymers have been used in the past.

Study of Properties of High-K Strontium Oxide Alignment Layer Using Solution Process for Low Power Mobile Information Device (저전력 휴대용 통신단말을 위한 Solution Process를 이용한 고 유전율 Strontium Oxide 배향막의 특성 연구)

  • Han, Jeong-Min;Kim, Won-Bae
    • Journal of Satellite, Information and Communications
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    • v.10 no.2
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    • pp.90-94
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    • 2015
  • We stuidied liauid crystal alignment treatment using solution process for making thin oxide layer in liquid crystal display. It is the one of very effient and popular process in making thin oxide layer in electronical industrial fields. Particularly, this process has highly potential value in liquid crystal display industrial fields because it cause automatically induced alignment process without tranditional alignment process in liquid crystal alignment process. We made several different kinds of mol density solutions using strontium oxide solution. And those solutions were treated for solidification layers using annealing process for 2 hours. And we stuided pretilt angle properties of these alignment layers of strontium oxide for clarifying the relationship of liquid crystal molecules and thin strontium oxide layer. And we also tested the existence of strontium oxide thin layer on substrate using XPS measurement. We expected the hig gain of electro-optical properties in liquid crystal display using strontium oxide thin layer because it has high K property material than the other metal-based oxide layers. In this results, we measured 1.447 to 1.613 thresholds volts as 0.1 mol to 0.4 mol density in 0.1 mol density steps. This is significant better characteristics than conventional liquid crystal display as higher than 1.85 thresholds volts. And it make possible to making next-generation liquid crystal display which present low-power consumption and wide gray scale in liquid crystal display.

Infrared Spectroscopic Study of Molecular Hydrogen Bonding in Chiral Smetic Liquid Crystal

  • Jang, Won-Gun
    • Journal of Information Display
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    • v.2 no.3
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    • pp.18-31
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    • 2001
  • We utilize Fourier transform infrared (IR) spectroscopy to probe intramolecular hydrogen bonding in $smectic-C^{\ast}$ liquid crystal phases. Infrared spectra of aligned smectic liquid crystal materials vs. temperature and of isotropic liquid crystal mixtures vs. concentration were measured in homologs, both with and without hydrogen bonding. Hydrogen bonding significantly changes the direction and magnitude of the vibrational dipole transition moments, causing marked changes in the IR dichroic absorbance profiles of hydrogen bonded molecular subfragments. A GAUSSIAN94 computation of the directions, magnitudes, and frequencies of the vibrational dipole moments of molecular subfragments shows good agreement with the experimental data. The results show that IR dichroism can be an effective probe of hydrogen bonding in liquid crystal phases.

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