• Title/Summary/Keyword: Light Uniformity

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Selection of Heater Location in Linear Source for OLED Vapor Deposition (OLED 증착을 위한 선형증발원 히터 위치선정)

  • Joo, Young-Cheol;Han, Choong-Hwan;Um, Tai-Joon;Lee, Sang-Wook;Kim, Kug-Weon;Kwon, Kye-Si
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.6
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    • pp.515-518
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    • 2008
  • Organic light emitting diode(OLED) is one of the most promising type of future flat panel display. A linear source is used to deposite organic vapor to a large size OLED substrate. An electric heater which is attached on the side of linear source heats the organic powder for the sublimation. The nozzle of heater, which is attached at the top of the linear source has an optimal temperature. An numerical analysis has been performed to find optimal heater position for the optimal nozzle temperature. A commercial CFD program, FLUENT, is used on the analysis. Two-dimensional and three-dimensional analysis have been performed. The analysis showed that the heater should be attached at the outer side of crucible wall rather than inner side of housing, which was original design. Eighteen milimeter from the top of the linear source was suggested as the optimal position of heater. Improving thermal performance of linear source not only helps the uniformity of organic vapor deposition on the substrate but also increase productibity of vapor deposition process.

Realization of the Real-time Hybrid Optical Interconnection Using a Genetic Algorithm (GA 학습기법을 적용한 실시간 복합 광 연결의 실현)

  • Yoon, Jin-Seon;Kim, Nam
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.9
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    • pp.38-46
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    • 2000
  • In this paper, a grating to apply for the optical interconnection is designed using a Genetic Algorithm(GA) as a robust and an efficient schema. A hybrid optical interconnection system architecture is implemented by the liquid crystal panel as a programmable spatial light modulator. As the result of geometrical transformation to obtain the quantitative data for $3{\times}3$ spot beams at CCD array detector by optical experiment truthfully, the mean of beam intensity as a gray level is 202, the maximum value is 225, the minimum value is 186, and a uniformity is quantitatively $1.93{\times}10^{-1}$ similar to simulation result.

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Electroless Nickel Plating on Fibers for the Highly Porous Electrode

  • Cheon, So-Young;Park, So-Yeon;Rhym, Young-Mok;Kim, Doo-Hyun;Koo, Yeon-Soo;Lee, Jae-Ho
    • Journal of Electrochemical Science and Technology
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    • v.1 no.2
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    • pp.117-120
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    • 2010
  • Materials used as fuel cell electrode should be light, high conductive, high surface area for reaction, catalytic surface and uniformity of porous structure. Nickel is widely used in electrode materials because it itself has catalytic properties. When used as electrode materials, nickel of only a few im on the surface may be sufficient to conduct the catalytic role. To manufacture the nickel with porous structure, Electroless nickel plating on carbon fiber be conducted. Because electroless nickel plating is possible to do uniform coating on the surface of substrate with complex shape. Acidic bath and alkaline bathe were used in electroless nickel plating bath, and pH and temperature of bath were controlled. The rate of electroless plating in alkaline bath was faster than that in acidic bath. As increasing pH and temperature, the rate of electrolee plating was increased. The content of phosphorous in nickel deposit was higher in acidic bath than that in alkaline bath. As a result, the uniform nickel deposit on porous carbon fiber was conducted.

A Study on pricess characteristics of $ZrO_2$ films prepared on poly-ethlene naphthalate by using Facing tagets sputtering system (대향타겟식 스퍼터링 방법에 의해 PEN 기판위에 성막된 $ZrO_2$ 박막의 공정 특성에 관한 연구)

  • Cho, Do-Hyun;Kwon, Oh-Jung;Wang, Tae-Hyun;Kim, Ji-Hwan;Park, Sung-Hwan;Hong, Woo-Pyo;Kim, Hwa-Min;Kim, Jong-Jae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.423-424
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    • 2008
  • A facing target sputtering (FTS) equiment is fabricated and its process characteristics are investigated to search for the possibility of applications to film passivation system for organic light emitting diodes (OLEDs). We report that the FTS system can prepare a high quality $ZrO_2$ films with a dense micro structure and an excellent uniformity less than 5% and a high transmittance over an average 80% in the visible range. We suggest that the FTS is one of the suitable deposition techniques for the thin film passivation layer of OLEDs and the gas barrier layer of polymer substrate.

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The Fabrication of (Ga, Al) As/GaAs Modified Multi-Quantum Well Laser Diode by MOCVD (MOCVD법에 의한 (Ga, Al) As/GaAs 변형된 영지우물 레이저 다이오드의 제작)

  • Kim, Chung-Jin;Kang, Myung-Ku;Kim, Yong;Eom, Kyung-Sook;Min, Suk-Ki;Oh, Hwan-Sool
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.9
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    • pp.36-45
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    • 1992
  • The Modified Multi-Quantum Well(MMQWAl) structures have been grown by Mental-Organic chemical Vapor Deposition(MOCVD) method and stripe type MMQW laser diodes have been investigated. In the case of GaAs/AlGaAs superlattice and quantum well growth by MOCVD, the periodicity, interface abruptess, Al compositional uniformity and layer thickness have been confirmed though the shallow angle lapping technique, double crystal x-ray diffractometry (DCXD) and photoluminescence (PL) measurement. stripe-type MMQW laser diodes have been fabricated using the process technology of photolithography, chemical etching, ohmic contact, back side removing and cleaving. As the result of the electrical and opticalmeasurement of these laser diodes, we have achieved the series resistance of $1[\Omega}~2{\Omega}$ by current-voltage measurements, the threshold current of 200-300mA by currnt-light measurements and the lasing wavelength of 8000-8400$\AA$ by lasing spectrum measurements.

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Flat Fluorescent Lamp with Good Uniformity for LCD Back-Light (훌륭한 휘도 균일도를 갖는 LCD 후면 광원용 평판 형광램프)

  • Kwon, Soon-Seok;Yoon, Geel-Joong
    • Journal of the Institute of Electronics Engineers of Korea TE
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    • v.37 no.1
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    • pp.12-17
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    • 2000
  • In this paper, the frequency characteristics of flat fluorescent lamp(FFL) using ultraviolet generated from gas discharge are studied. The lamp is a simple structure with insulator layer, phosphor layer, and gas gap(1.1mm). The firing voltage and uniform voltage was decreased with increasing the frequency. It was considered that this tendency was resulted from the space charge effect due to Xe and Ar positive ions trapped in gas gap. Luminance in FFL using Xe as discharge gas was shown 2700 cd/$m^2$ in operation (700 Vrms, 80 kHz). Hence, the maximum luminous efficiency was 5 lm/W.

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Deposition of SiO2 Thin Film for the Core of Planar Light-Wave-Guide by Transformer Coupled Plasma Chemical-Vapor-Deposition (TCP-CVD 장비를 활용한 광도파로용 Core-SiO2 증착)

  • Kim, Chang-Jo;Shin, Paik-Kyun
    • Journal of the Korean Vacuum Society
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    • v.19 no.3
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    • pp.230-235
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    • 2010
  • In this paper, we controlled the deposition rate and reflective index with process conditions that are TCP power, gas flow ratio and bias for optical properties of $SiO_2$ thin film using TCP-CVD equipment. We obtained a excellent $SiO_2$ thin film which has a excellent uniformity (<1 [%]), deposition rate (0.28 [${\mu}m$/ min]) and reflective index (1.4610-1.4621) within 4" wafer with process conditions ($SiH_4:O_2$=50 : 100 [sccm], TCP power 1 [kW], bias 200 [W]) at [$300^{\circ}C$].

The Research for Remote-indicating Magnetic Compass(I) (원격지시식 자기 compass 에 관한 연구(I))

  • 이상집;임정빈
    • Journal of the Korean Institute of Navigation
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    • v.10 no.1
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    • pp.81-100
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    • 1986
  • Self-contained portable remote-indicating magnetic compass was designed and tested. Its sensing part consists of main scale disk of rotary encoder with photo-etched 180, oopaque slits and three pairs of light sources and detectors seperated by a transparent index scale, so that any angular deflection of main scale disk against the bowl may be detected optically. The outputs from the sensing part are transformed into digital ship's course indication by electronics unit which consists of operational amplifier, phase discriminator, up-down counter and counting starter circuit. The results from testign the above compass with turntable at variable rate of turn are as following : 1) The main scale disk deflection against the bowl can be detected without any disturbing influence to the freedom of its north-seeking function. 2) The digital indication resolution is found to be $\circ \pm$1 degree. 3) Misrepresenting indication can be avoided by ensuring dimension uniformity and arrangement accuracy of slits on main and index scale disks and by centering pivot in the encoder disk. 4) Indication resolution should be improved by modifying the signal processing and by doubling the number of slits on compass card. 5) Further study should be made on developing non-conductive compass liquid, analogue repeater driving system and more compact processing element.

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The Study of White uniformity improvement in TFT LCD using LED (LED적용 TFT-LCD 외관 백색 균일도 향상을 위한 광선 추적 시뮬레이션 연구)

  • Lee, San-Hwan;Yi, Jun-Sin;Lee, Seung-Jae
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1665-1666
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    • 2006
  • TFT-LCD(Thin Film Transistor Liquid Crystal Display)는 표시장치로서 실용화된 후 많은 상품에 적용중이다. 그러나, LCD는 자체 발광능력이 없으므로 그후면에서 LCD 화면을 밝혀주는 BLU(Backlight Unit)를 필요로 한다. BLU는 내부 광원으로 밝기가 균일한 평면광을 만들어 LCD 화면을 균일하게 면조사하는 역할을 한다. LCD가 적용되는 분야중 Note PC에는 광원으로 CCFL(Cold Cathode Fluorescent Lamp)가 적용되어 왔지만, 최근 고휘도, 박형화, 저소비 전력을 달성하기 위해 CCFL로는 한계가 있어 LED(Light Emitting Diode)를 적용한 BLU를 제작하기 위한 연구가 진행되고 있다. 본 연구에서는 점광원인 LED 적용한 LED에 있어서 요구되는 휘도 균일성을 향상시키기 위해서는 LED광원이 적용된 BLU의 외관 품질 향상을 위한 도광판 입광부 구조 최적화를 광추적 Simulation을 통해 예측하고 향상시킬 수 있는 구조를 제안한다. Simulation결과, 외관품질 개선을 위해 도광판 입광면에 130도의 Serration과 휘도를 향상하기 위해 도광판 밑면에 렌즈 형상의 바 구조를 도출해 적용한 결과 외관품질향상과 휘도향상을 얻었다.

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Permanent Support for Tunnels using NMT

  • Barton, Nick
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 1995.03a
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    • pp.1-26
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    • 1995
  • Key aspects of the Norwegian Method of Tunnelling (NMT) are reviewed. These include a predictive method of support design using the six-parameter Q-system of rock mass characterisation. The rock mass rating or Q-value is updated during tunnel driving. The designed tunnel support generally consists of wet process, steel fibre reinforced shotcrete combined with fully grouted, untensioned rock bolts, Even in poor rock conditions S(fr) + B usually acts as the final rock reinforcement and tunnel lining. Since it is a drained lining, it is very economic compared to cast concrete with membranes. Light, free-standing steel liners are used to prevent water affecting the runnel environment. Rock mass conditions, and hence lining design and cost estimation can be assessed by careful use of seismic surveys. Relationships between the P-wave velocity, the rock mass deformation modulus and the Q-value have recently been established, where tunnel depth, rock porosity and the uniaxial compression strength of the rock are important variables. The rock mass modulus estimate, and simple index testing of the joints, provide the key input which joints are discretely represented (either in two dimensions with the UDEC code or in three dimensions with the 3DEC code) is generally favoured compared to continuum analysis. The latter may give a misleading impression of uniformity and deformations tend to be understimated. Q-system NMT designs of S(fr) + B (fibre reinforced shotcrete and bolting) are numerically checked and adjustments made to bolt capacities and shotcrete thickness if overloading is evident around the modelled profile.

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