• Title/Summary/Keyword: Light-off

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Patterning of Conductive Polymer Anodes Using a Peel-off Method

  • Park, Jong-Woon;Yim, Youn-Chan;Heo, Gi-Seok;Lee, Jong-Ho;Kim, Tae-Won;Kim, Gwang-Young
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.868-870
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    • 2009
  • Here we report another soft lithography, peel-off method, for patterning conductive polymer anodes in the fabrication of flexible ITO-free organic light-emitting diodes. This method doesn't require any heating process and UV light. We have demonstrated that such a peel-off technique enables the formation of a very sharp edge and the enhancement of edge roughness.

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Analysis of Effects on the performance of ceramic metal halide lamp by the loss of elements that have been filled in arc tube

  • Jang, Hyeok-Jin;Yang, Jong-Gyeong;Lee, Jong-Chan;Kim, U-Yeong;Sin, Ik-Tae;Park, Dae-Hui
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.219-219
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    • 2009
  • ceramic metal halide lamps are a subset of high intensity discharge lamps so named because of their high radiance These lamps weak ionized plasma in a fire-resisting but light transmissive wrapping by the corridor of current through atomic and molecular vapors. for commercial applications, For commercial applications, the conversion of electric power to light must occur with good efficiency and with sufficient spectral content throughout the visible (380-800 nm) to permit the light so generated to render colors comparable to natural sunlight. the purpose of this paper is to carry out a study on the variation of ageing time(2000 On/Off[hr]) on the performance of 150W CMH lamps. Experimental results show that the blackening by reacting W(tungsten)with I atomic has been created in the arc tube of an ageing lamp(2000 On/Off[hr]), the arc was unstable, and increased a lamp resistance made lamp voltage increases significantly. Also, Color temperature of the ageing lamp was moved by the losses of Ho with Dy atomics and by recombination of Na with I.

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A Study on Characteristics of Exhaust Gas Temperature Uniformity and Light-off in Motorcycle Catalytic Converter (2륜 자동차 촉매변환기내 배기가스 온도균일도 특성과 Light-Off에 관한 연구)

  • Yi, Chung-Seub;Jeong, Hyo-Min;Lee, Cheol-Jae;Chung, Han-Shik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.6 s.261
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    • pp.507-513
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    • 2007
  • This study represents the temperature uniformity in catalytic converter. Present research model type is a monolithic catalytic converter. This type was been widely used for complying the regulations of pollutant emissions from automobiles. The mean experimental parameters are engine speed and ceramics monolith in the catalytic converter. The experimental test engine model used was the 124.1cc motorcycle engine. The experimental study using thermal imaging method shows the megaphone type model has larger effective area than the basic model. The rate of effective area in the basic model is about 8.9 % and the megaphone type model are 41.52 %, 34.60 %, 33.43 %, 25.43 %, 17.82 % according to the diffuser angle $4^{\circ}\;to\;8^{\circ}$. In conclusion, the megaphone type monolithic converter has higher efficiency of reducing the pollution with less noise compared to the basic shape. We believe this will be very important as a design guide of the advanced motorcycle.

The correlation of the halo mura and off-axis light leakage level in LCDs with 2D dimmable LED backlight system

  • Kwon, Jang-Un;Byun, Min-Chul;Ham, Jung-Hyun;Baek, Heume-Il;Moon, Hong-Man;Shin, Hyun-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.590-593
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    • 2009
  • In the 2D local dimmable LED backlight system, each LED segment can be controlled separately. This can enhance the contrast ratio and reduce overall power consumption of LCDs. However, an artifact such as 'halo mura' can be observed around the bright object in the dark background. This is caused by the light leakage from the bright area into the dark one. Therefore, the 'halo mura' can be more easily observed in the oblique viewing direction. Thus, in this study, the perceivable degree of the halo mura is evaluated according to the level of the off-axis light leakage of LCDs. It is found that an acceptable degree of halo mura can be obtained in 2.0 cd/$m^2$ of the diagonal light leakage. In addition, the halo mura is unperceivable under 0.7 cd/$m^2$ of the diagonal light leakage which can be achieved with optimally compensated polarizers.

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Characteristics and Fabrication of Vertical Type Organic Light Emitting Transistors Using n-Type Organic Materials (N형 유기물질을 이용한 세로형 유기 발광트랜지스터의 제작 및 특성에 관한 연구)

  • Oh Se-Young;Kim Hee-Jeong;Jang Kyoung-Mi
    • Polymer(Korea)
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    • v.30 no.3
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    • pp.253-258
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    • 2006
  • We have fabricated vortical type organic thin film transistors (OTFTs) consisting of ITO/n type active material/Al gate/n type active material/Al using F16CuPc, NTCDA, PTCDA and PTCDI C-8. The effect of mobility of n type active materials and thin film thickness on current-voltage (I-V) characteristics and on/off ratios were investigated. The vortical type organic transistor using PTCDI C-8 exhibited low operation voltage and high on-off ratio. In addition, we have investigated the feasibility of application in organic light emitting transistor using light emitting polymer. Especially, the light emitting transistor consisting of ITO/PEDOT-PSS/P3HT/F16CuPc/Al gate/F16CuPc/Al showed the maximum quantum efficiency of 0.054.

Study on Heat-shield Property of Surface-treated Inorganic Oxide Particles (표면처리된 무기산화물 입자의 열차단 특성에 관한 연구)

  • Kim, Dong Ho;Kim, Gu Ni
    • Journal of Adhesion and Interface
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    • v.14 no.1
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    • pp.28-35
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    • 2013
  • In this study, we produced heat-shield coating materials using surface-treated Ga-doped ZnO (GZO) and investigated the dispersity of particle, visible light transmittance, ultraviolet light cut off, infrared light cut-off, heat-shielding property by surface-treating compounds and treatment conditions. In the case of using IPA or acryl binder for heat-shield coating, the dispersity of inorganic oxide particles was poor but in the case of using surface-treated inorganic oxide particles by hybrid compound having urethane (urea) group, acryl group and silica, dispersity of particle, visible light transmittance and haze were improved. We used the measurement kit and sunlamp for measuring heat-shielding property and confirmed that the internal temperature of the measurement kit using heat-shield film was lower more than $4.8^{\circ}C$ in comparison with using PET film for itself.

Optical Compensation in a Vertical Alignment Liquid Crystal Cell for Elimination of the Off-Axis Light Leakage

  • Ji, Seung-Hoon;Choi, Jung-Min;Lee, Gi-Dong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1580-1583
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    • 2008
  • We propose an optical configuration for a vertical alignment (VA) liquid crystal (LC) cell to eliminate the off-axis light leakage in the dark state. The proposed compensation configuration consists of a positive A-film, a positive C-film and a negative C-film. The optical design is performed on a Poincar$\acute{e}$ sphere. This configuration has a better tolerance to the wavelength dispersion, as the polarization trace could self-compensate it. From calculations, we show that the proposed VA LC cell can improve the viewing angle characteristics by compensating for the light leakage in the diagonal direction.

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Ultraviolet and visible light detection characteristics of amorphous indium gallium zinc oxide thin film transistor for photodetector applications

  • Chang, Seong-Pil;Ju, Byeong-Kwon
    • International journal of advanced smart convergence
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    • v.1 no.1
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    • pp.61-64
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    • 2012
  • The ultraviolet and visible light responsive properties of the amorphous indium gallium zinc oxide thin film transistor have been investigated. Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor operate in the enhancement mode with saturation mobility of $6.99cm^2/Vs$, threshold voltage of 13.5 V, subthreshold slope of 1.58 V/dec and an on/off current ratio of $2.45{\times}10^8$. The transistor was subsequently characterized in respect of visible light and UV illuminations in order to investigate its potential for possible use as a detector. The performance of the transistor is indicates a high-photosensitivity in the off-state with a ratio of photocurrent to dark current of $5.74{\times}10^2$. The obtained results reveal that the amorphous indium gallium zinc oxide thin film transistor can be used to fabricate UV photodetector operating in the 366 nm.

Performance Analysis of Optical Path Difference on Visible Light Communication System for Intelligent Transport Systems

  • Choi, Jae-Hyuck;Lee, Kye-San;Cha, Jae-Sang;Kim, Jin-Young
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.5
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    • pp.114-120
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    • 2009
  • In outdoor visible light communication channels and LED road illumination communications for the intelligent transport systems (ITS), inter symbol interference (ISI) due to multipath propagation prevents high data rate transmission. Indoor wireless optical communication systems utilizing white LED lights and on the road illumination have been studying about it. Generally, plural lights are installed in room and considered to the traffic information system using existing LED traffic lights. Therefore, their optical path difference must be considered. In this paper, the influence of an optical path difference has been investigated and two approaches against this problem are introduced. One uses on-off keying, return-to-zero (OOK-RZ) coding and the other uses optical orthogonal frequency division multiplexing(OFDM).

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Performance Analysis of Indoor Visible Light Communication Systems (실내 가시광 통신 시스템의 성능 분석)

  • Choi, Jae-Hyuck;Kim, Sung-Ill;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.7-11
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    • 2008
  • Future electric lights will be composed of white LEDs (Light Emitting Diodes). Indoor wireless optical communication systems utilizing white LED lights have been studying about it. Generally, plural lights are installed in room. Therefore, their optical path difference must be considered. In this paper, the influence of an optical path difference has been investigated and two approaches against this problem are introduced. One uses OOK-RZ (On-Off Keying, Return-to-Zero) coding and the other uses optical OFDM (Orthogonal Frequency Division Multiplexing). From the results of computer simulations, we have found that these approaches are feasible for the wireless optical communication systems utilizing white LED lights.

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