• Title/Summary/Keyword: advanced angle

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Study on In-Plane Switching mode with discotic compensation film (Discotic 필름 보상형 In-Plane Switching 모드에 관한 연구)

  • Song, I.S.;Baik, I.S.;Jung, B.S.;Jeon, Y.M.;Lee, S.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.518-521
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    • 2004
  • We have investigated about compensation film to reduce the light leakage at an oblique angle in-plane switching mode. It is well known that uncompensated in-plane switching (US) and fringe field switching (FFS) liquid crystal displays (LCDs) have much better viewing angle than other modes owing to the in-plane rotation of the LC director. However, to accomplish optimal viewing angle characteristics in these devices, they must be compensated by one or more films. So, in this paper, we have studied how to reduce the light leakage with viewing angle using discotic film in dark state.

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Enhancement of pretilt angle using blending polyimide

  • Lee, Sang-Gu;Shin, Sung-Eui;Choi, Kil-Yeong;Yi, Mi-Hie;Shin, Dong-Myung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.317-319
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    • 2008
  • Photo-alignment layer which contains cinnamate is difficult to generate pretilt angle of liquid crystals. In order to enhance pretilt angle, blending poly (amic acid) between containing fluorine poly (amic acid) and 1,2,3,4-cyclobutanetetracaroxylic dianhydride (CBDA) / 3,5-diaminobenzyl alcohol (DBA) were used. For photoreaction, cinnamate was conjugated by interfacial reaction with blending polyimide.

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Imperfection Parameter Observer and Drift Compensation Controller Design of Hemispherical Resonator Gyros

  • Pi, Jaehwan;Bang, Hyochoong
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.4
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    • pp.379-386
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    • 2013
  • The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.

Optical fiber polishing technique using a CO2 laser (CO2 레이저를 이용한 초정밀 광섬유 연마 레이저 기술)

  • Choi, Hun-Kook;Sohn, Ik-Bu;Noh, Young-Chul;Jung, Deok;Lee, Man-Seop;Lee, Seo-Young;Lee, Hyung-Jong
    • Laser Solutions
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    • v.16 no.2
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    • pp.12-15
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    • 2013
  • In this paper, we controlled the edge angle of fiber by using $CO_2$ laser. In order to control the angle, tilting angle of fiber on stage and the number of scan repetition are adjusted, and laser power is fixed at 30 W in the experiment. In the polishing result, the edge angle of fiber can be changed from $4^{\circ}$ to $8^{\circ}$, as changing the tilting angle and the number of scan repetition. This $CO_2$ laser polishing can fabricate ball lenses with various curvatures and a sharp probe as well as the edge angled fiber.

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Light Leakage Comparison in a Homogeneously Aligned Nematic Liquid Crystal Display Depending on an Angle between Polarizer Axis and Optic Axis of a Liquid Crystal

  • Song, I.S.;Baik, I.S.;Won, H.K.;Kim, D.S.;Soh, H.S.;Kim, W.Y.;Lee, S.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1182-1184
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    • 2004
  • We have studied contrast ratio of a homogeneously aligned nematic liquid crystal (LC) display as a function of the angle between the polarizer axis and LC director. The results show that a cell configuration in which a polarizer axis facing a light source coincides with a short LC axis has a better process margin in terms of high contrast ratio than that of the cell coinciding with a long LC axis.

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Facile preparation of superhydrophobic thin films using non-aligned carbon nanotubes

  • Goh, Yee-Miin;Han, Kok Deng;Tan, Lling-Lling;Chai, Siang-Piao
    • Advances in nano research
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    • v.2 no.4
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    • pp.219-225
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    • 2014
  • A simple preparation method on creating superhydrophobic surface using non-aligned carbon nanotubes (CNTs) was demonstrated. Superhydrophobic CNT thin films were prepared by doping a sonicated mixture of CNTs and chloroform onto a glass slide. Water contact angles of the CNT thin films were measured using a contact angle goniometer. The thin films were characterized using laser microscope and scanning electron microscope. Experimental results revealed that the highest average contact angle of $162{\pm}2^{\circ}$ was achieved when the films' thickness was $1.628{\mu}m$. The superhydrophobic surface was stable as the contact angle only receded from $162{\pm}2$ to $157{\pm}2^{\circ}$ after 10 min under normal atmospheric condition.

Hand motion estimation for interactive image composition (상호작용 영상합성을 위한 손의 움직임 추정)

  • Koo, Ddeo-Ol-Ra;Seo, Yung-Ho;Doo, Kyoung-Soo;Choi, Jong-Soo
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.951-952
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    • 2008
  • This paper proposes a new method for image composition which estimates the rotation angle of human hand and uses the reserved image in real-time camera images. First, we capture a background image and extract a interesting region by background subtraction. Next, we estimate the skin region from the interesting region and calculate the rotation angle of estimated skin region using PCA(Principal Components Analysis). Finally, we composite the reserved image for the calculated rotation angle in camera images. The proposed method can be applied to control the 3D avatar for marker-less augmented reality.

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Distance Measurement Using Infrared Sensor On Curved Surface (적외선 센서를 이용한 곡면에서의 거리 측정)

  • Min, Deok Ho;Jeong, Min-Jae;Kim, Hyung Jin;Seo, Young Ho;Kim, Byeong Hee
    • Journal of Industrial Technology
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    • v.37 no.1
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    • pp.27-31
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    • 2017
  • In this paper, we have extended the research on the infrared sensor which has been limited to the plane. The reflection mechanism of the light on the curved surface is analyzed according to the curvature change and the emitted angle of photodiode and verified through experiments. The difference in the curvature causes a difference in the measurement distance, and also changes the intensity of the light coming into the phototransistor, thereby causing a difference in the output voltage. However, the difference in the output voltage due to the curvature change can be solved by adjusting the emitted angle of the photodiode to minimize the spot area formed on the curved surface regardless of the curvature. Therefore, it is possible to measure the distance by using the infrared sensor regardless of the curvature by aligning the photodiode to the center of the curved surface and adjusting the angle of the photodiode.

CO2 Laser Assisted Fabrication of Micro-lensed Single-mode Optical Fiber

  • Choi, Hun-Kook;Yoo, Dongyoon;Sohn, Ik-Bu;Noh, Young-Chul;Sung, Jae-Hee;Lee, Seong-Ku;Jeong, Tae-Moon;Ahsan, Md. Shamim;Kim, Jin-Tae
    • Journal of the Optical Society of Korea
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    • v.19 no.4
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    • pp.327-333
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    • 2015
  • This paper reports the fabrication of various micro-lensed single-mode optical fibers through the use of an enhanced peak power $CO_2$ laser beam. The end faces of the optical fibers are exposed to the $CO_2$ laser beam to form convex, concave, and conical shape optical fiber tips. Peak power of the $CO_2$ laser beam was varied from 0.8 W to 1.5 W depending on the shape of the optical fiber tip. We also discover the dependence of the angle of the optical fiber tip on the rotation angle and the number of $CO_2$ laser irradiations. The angle shows an increasing trend with both these parameters. We achieve a wide range of lenticular fibers with end face angle varying from $4.47^{\circ}$ to $8.13^{\circ}$. Furthermore, we investigate the emission pattern of light from the developed micro-lensed fibers. The proposed $CO_2$ laser based optical fiber reshaping technique shows great consistency, and thus is suitable for commercial applications.

Impact Angle Control Guidance Synthesis for Evasive Maneuver against Intercept Missile

  • Yogaswara, Y.H.;Hong, Seong-Min;Tahk, Min-Jea;Shin, Hyo-Sang
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.4
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    • pp.719-728
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    • 2017
  • This paper proposes a synthesis of new guidance law to generate an evasive maneuver against enemy's missile interception while considering its impact angle, acceleration, and field-of-view constraints. The first component of the synthesis is a new function of repulsive Artificial Potential Field to generate the evasive maneuver as a real-time dynamic obstacle avoidance. The terminal impact angle and terminal acceleration constraints compliance are based on Time-to-Go Polynomial Guidance as the second component. The last component is the Logarithmic Barrier Function to satisfy the field-of-view limitation constraint by compensating the excessive total acceleration command. These three components are synthesized into a new guidance law, which involves three design parameter gains. Parameter study and numerical simulations are delivered to demonstrate the performance of the proposed repulsive function and guidance law. Finally, the guidance law simulations effectively achieve the zero terminal miss distance, while satisfying an evasive maneuver against intercept missile, considering impact angle, acceleration, and field-of-view limitation constraints simultaneously.