• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.134-137
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• 2010

We have proposed a transflective liquid crystal display (LCD) driven by the fringe field using a liquid crystal (LC) with a negative dielectric anisotropy. The device used different twist angles of the liquid crystals (LC) in the transmissive (T) and the reflective (R) regions when voltage is applied. With the optimization of the pixel electrode width and the distance between them, the LC directors in the R- and T-regions can be rotated by about $22.5^{\circ}$ and $45^{\circ}$ on an average, respectively. As a result, a high image quality transflective LCD with a single gap, a single gamma, and a wide viewing angle characteristics in both the R- and T- regions can be realized.

• Journal of the Korean Geophysical Society
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• v.2 no.2
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• pp.123-134
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• 1999

Magnetotelluric responses may be affected by strong anisotropy of the high-conductivity layers (HCL) in the upper mantle or lower crust. We have studied two-dimensional anisotropy MT modelling to examine the effect of high anisotropic media. Electrical properties of a homogeneous anisotropic body are defined by a symmetric conductivity tensor and the problem is described by coupled diffusion equation in the frequency domain. In two-dimensional anisotropic environments, diagonal elements of the impedance tensor have higher values than those in isotropic environments. In some cases, TM mode phases reach more than 90°and apparent resistivities decrease for some frequency range because of telluric distortion. GB decomposition may be used to recover regional responses, but can be affected by the regional anisotropic effect. Considering these results, BC87 dataset was interpreted with a modified anisotropic model.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.1
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• pp.67-72
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• 1991

For improving the magnetic properties of the amorphous Fe-B-Si alloy, we annealed the sample in a magnetic field oriented in the plane of the ribbon longitudinal to its long axis. By field annealing, coercive force and total core loss are reduced from 0.04 Oe to 0.02 Oe, and from 0.25 watt/kg to 0.15 watt/kg respectively in comparsion with non-field annealed specimen. These reductions were caused by the formation of 180 dcmain wall parallel to the annealing field due to the induced anisotropy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.54-57
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• 2001

We have developed a new multidomain vertical-alignment (MVA) mode using a homeotropic photopolymer that provides a wider viewing angle for nematic liquidcrystal (NLC) with negative dielectric anisotropy. Good voltage-transmittance curves for he new MVA cell using the homeotropic photopolymer were observed. The viewing angle of the new MVA cell using the homeotropic photopolymer was wider than that of the conventional VA cell. The wide viewing angle using the new MVA cell is attributable to 4-domain by the ribs with UV exposure on the photopolymer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.158-158
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• 2009

This paper focuses on improving organic thin film transistor (OTFT) characteristics by controlling the self-organization of pentacene molecules with an alignable high-dielectric-constant film. The process, based on the growth of pentacene film through high-vacuum sublimation, is a method of self-organization using ion-beam (IB) bombardment of the $HfO_2/Al_2O_3$ surface used as the gate dielectric layer. X-ray photoelectron spectroscopy indicates that the IB raises the rate of the structural anisotropy of the $HfO_2/Al_2O_3$film, and X-ray diffraction patterns show the possibility of increasing the anisotropy to create the self-organization of pentacene molecules in the first polarized monolayer. An effective mobility of $2.3{\times}10^{-3}cm^2V^{-1}s^{-1}$ was achieved, which is significantly different from that of pentacene films that are not aligned. The proposed OTFT devices with an ultrathin $HfO_2$ structure as the gate dielectric layer were operated at a gate voltage lower than 5 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.116-116
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• 2009

This paper focuses on improving organic thin film transistor (OTFT) characteristics by controlling the self-organization of pentacene molecules with an alignable high-dielectric-constant film. The process, based on the growth of pentacene film through high-vacuum sublimation, is a method of self-organization using ion-beam (IB) bombardment of the $HfO_2/Al_2O_3$ surface used as the gate dielectric layer. X-ray photoelectron spectroscopy indicates that the IB raises the rate of the structural anisotropy of the $HfO_2/Al_2O_3$ film, and X-ray diffraction patterns show the possibility of increasing the anisotropy to create the self-organization of pentacene molecules in the first polarized monolayer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1054-1057
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• 2003

We have studied $90^{\circ}$ twisted nematic (TN) mode driven by fringe electric field, where two polarizers are parallel each other such that the cell shows a black state before a voltage is applied. According to the studies by computer simulation for a LC with negative dielectric anisotropy, the LC twists perpendicular to the horizontal field direction of fringe electric field and the degree of tilt angle is very low, when a voltage is applied. Therefore, the new device exhibits wide viewing angle characteristic due to in-plane switching and high transmittance since the LC director aligns parallel to the polarizer axis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.198-201
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiO thin film. The homogenous alignment can be obtain어 using ion beam (IB) exposure on the SIO thin film, when positive type NLC ($Delta\varepsilon$>0) was injected However, the homeotropic alignment can be obtained using ion beam (IB) exposure on the SiO thin film, when negative type NLC ($\Delta\varepsilon$>0) was injected The LC aligning ability on the SiO thin film depends on the dielectric anisotropy type of LC. It will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.312-313
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• 2008

A transflective liquid crystal displays associated with fringe field switching (FFS) mode of new concept is proposed. The device utilizes unique characteristic of the FFS mode in which the rotation angle of LC director is strongly dependent on electrode position in on state. We use the liquid crystal with negative dielectric anisotropy. Also we are look for optimized electrode size and the optimization of pixel electrode width and distance between them, the LC director could rotate about $22.5^{\circ}$ and $45^{\circ}$ depending on electrode positions. Consequently, we get high transmittance and high reflection on the optimized electrode condition. Respectively, a high image quality transflective display with single gap and single gamma characteristics realized.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.791-795
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• 2000

Amorphous chalcogenide glasses have a wide variety of light-induced effects. In this study, we have investigated the diffraction efficiency of chalcogenide. As$_{40}$ Ge$_{10}$ Se$_{15}$ S$_{35}$ thin films by the various applied electric fields. The holographic grating in these thin films has been formed using a linearly polarized He-Ne laser light (633nm). The diffraction efficiency was investigated the two method of applied electric field in the perpendicular and parallel to the direction of inducing beam. We obtained that properties of diffraction efficiency in the two methods of applied electric field. The result is shown that the diffraction efficiency of parallel electric field is 285% increase, η=1.1$\times$10$^{-3}$ and the diffraction efficiency of perpendicular electric field is 80% decrease, η=9.83$\times$10$^{-5}$ . Also, we have investigated the anisotropy property on chalcogenide thin films by the electric field effects.