• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1008-1011
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• 2005

In this study, the field emission display with carbon nanotube emitter is developed for the large size HDTV application. Two structures for electron beam focusing are developed on the typical top-gate cathode. The metal grid and focusing gate structure are proved to be effective for the focusing. The data switching voltage for the double gate structure is lower than 30V which is competitive value in respect of the cost for driver electronics. The brightness and color gamut are comparable to those of the commercial product such as CRT.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1470-1473
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• 2005

We proposed new triode-type Field Emitter Arays using Carbon NanoTubes(CNT-FEAs) as electron emission sources at low electric fields. The CNTs were selectively grown on the patterned catalyst layer by Plasma-Enhanced Chemical Vapor Deposition (PECVD). In this structure, gate electrodes are located underneath the cathode electrodes and extracted gate is surrounded by CNT emitters. Furthermore, in order to control density of CNTs, we investigated effect of using rapid thermal annealing (RTA).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.446-446
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• 2010

탄소나노튜브(CNT, carbon nanotube)를 에미터 재료로 사용하여 전계방출 디스플레이 (FED, field emission display)용 캐소드(cathode)를 제작할 때 CNT paste를 구성하는 유기성 바인더를 제거하기 위한 열처리 공정은 필수적이며, 이후에 CNT의 돌출을 위한 표면처리 공정이 뒤따르게 된다. 이러한 표면처리에는 여러 가지 방법들이 있으며 캐소드 제작시 매우 중요한 부분이다. 그 이유는 열처리 과정을 거치게 되면 이물질들이 CNT를 감싸게 되는데 이는 전계방출을 방해하는 요소가 되기 때문에 이를 효과적으로 제거해주지 않으면 전계방출의 효율성이 떨어지기 때문이다. 본 연구는 스크린 인쇄법으로 제작한 CNT 캐소드의 표면처리에 관한 것으로 Tpae 방법을 이용하여 1차적으로 표면처리를 수행한 후 2차적으로 재열처리법을 이용하여 열처리 후 CNT를 감싸고 있는 이물질(ash, residue)등을 효과적으로 제거하였는지 전계방출 특성을 통하여 알아보았다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.284-285
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• 2003

Significant research interest in the growth and characterization of $Y_2$O$_3$：Eu$^{3+}$ thin films has been shown over the last few years because of the promise for applications of display devices. Although an Eu-doped oxysulfide (Eu： $Y_2$O$_2$S) which has an efficiency of 13％ has been used for a traditional cathode ray tube (CRT) red phosphor, the sulfide system is known to degrade rapidly under the high current densities needed for field-emission display (FED) technology. (omitted)d)

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.95-97
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• 1999

A 3.12" FED panel was packaged successfully using the anode plate on which phosphors and black matrix were coated and cathode plate containing emitter arrays. The vacuum level of the panel was investigated during panel evacuation, tip-off and getter activation process. The packaged panel exhibited vacuum level below 2${\times}$10-6 Torr. Similar experiments were carried out for 10" panel made of bare plates. In addition, the vacuum level of two panels was compared continuously after tip off process; one with the getter and the other without it.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.32-39
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• 2015

This paper presents the surface flashover mechanism of a laminated solid dielectric and describes the surface flashover characteristics with the inherent capacitance of the laminated solid dielectric in a $N_2/O_2$ mixture gas (8:2) under an quasi uniform field. It was found that the electron emission at a cathode and the high-local electric field region around an anode were important factors to reasonably describe the surface flashover mechanism. The surface flashover voltage by the mechanism decreased with the inherent capacitance increase of the laminated solid dielectric. In addition to the surface flashover mechanism and its characteristics, the surface flashover voltage equations as a function of the inherent capacitance were derived by considering a gas pressure used in future eco-friendly GIS and the factors influencing the surface flashover.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.123-123
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• 2003

탄소나노튜브는 지금까지의 많은 연구를 통해 다양한 분야에 대한 응용 가능성이 확인되었으며, 그 중에서도 특히 탄소나노튜브를 이용한 전계방출표시소자(carbon nanotube field emission display, CNT-FED)는 상용화를 눈앞에 두고 있는 상황이다. 본 연구에서는 탄소나 노튜브를 합성할 수 있는 여러 가지 방법 중에서 열화학기상증착법(thermal chemical vapor deposition, thermal CVD)을 이용하여 유리기판 위에 탄소나노튜브를 합성하였다. Electron beam evaporation으로 유리기판 위에 전극층으로 Cr을 150nm를 증착하고 연속하여 촉매층인 Invar(Fe-53%Ni-6%Co 합금)를 10nm의 두께로 형성하였다. 사진식각으로 Cr층을 line 패턴한 후 Cr line 내의 Invar층을 line 및 dot 패턴하였다. 나노튜브 합성을 위해 480-58$0^{\circ}C$까지 진공분위기 또는 질소 분위기에서 20분간 승온한 후 CO(150sccm)와 H$_2$(1200sccm)를 주입하여 20분간 성장시키고 질소 분위기에서 냉각시켰다. 성장된 탄소나노튜브는 SEM, TEM, Raman spectroscopy 등을 통하여 구조 및 형상분석을 하였다. 진공승온의 경우 탄소불순물인 a-C이 많은 양 증착 되었으며 탄소나노튜브는 온도에 따라 1-5$\mu\textrm{m}$의 두께로 성장하였으나, 질소분위기 승온의 경우는 a-C이 거의 증착되지 않았으며 나노튜브의 두께가 10-20$\mu\textrm{m}$였다. 본 연구에서는 diode구조를 갖는 탄소나노튜브 에미터의 수명예측을 위해 여러 가지 가속측정조건에서 전계방출 특성을 연구하였다. Anode와 cathode 간의 간격을 400$\mu\textrm{m}$로 유지한 diode 구조에 대해 $10^{-6}$ torr 이하의 진공에서 전계방출을 측정하였다. 100 line의 에미터를 60Hz의 주파수에서 1/100 duty로 구동하였으며, duty비 증가에 따라 pulse의 on-time을 고정하고 frequency를 변화시켰다. dc까지 duty비가 증가됨에 따라 방출전류의 양이 선형적으로 증가하였다. 전압을 일정하게 고정시키고 각 duty비에서 시간에 따라 방출전류를 측정한 결과 duty비가 높을수록 방출전류가 시간에 따라 급격히 감소하였다. 각 duty비에서 방출전류의 양이 1/2로 감소하는 시점을 에미터의 수명으로 볼 때 duty비 대 에미터 수명관계를 구해 높은 duty비에서 전계방출을 시킴으로써 실제의 구동조건인 낮은 duty비에서의 수명을 단시간에 예측할 수 있었다.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.371-378
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• 2004

The $SrGa_2S_4:Eu^{2+}$ green emitting phosphor has been studied as a luminous device for CRT (Cathode Ray Tube) or FED (Field Emission Display) and EL (Electroluminescence). This phosphor, also, is under noticed for LED (Lighting Emitting Diode) phosphor, which makes use of excitation characteristics of long wavelength region. The $SrGa_2S_4:Eu^{2+}$ phosphor was prepared generally conventional synthesis method using flux. However, this method needs high heat-treated temperature, long reaction time, complex process and harmful $H_2S$or $CS_2$ gas. In this works, therefore, we have synthesized $SrGa_2S_4:Eu^{2+}$ using SrS, $Ga_2S_3$, and EuS as starting materials, and the mixture gas of 5% H2/95% N2 was used to avoid the $H_2S$or $CS_2$. We investigated the luminescence characteristic of $SrGa_2S_4:Eu^{2+}$ phosphor prepared in various synthesis conditions, performed post-treatment and sieving process for application to LED.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.80-85
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• 2019

Vanadium dioxide is a well-known metal-insulator phase transition material. Lots of researches of vanadium redox flow batteries have been researched as large scale energy storage system. In this study, vanadium oxide($VO_x$) thin films were applied to cathode for lithium ion battery. The $VO_x$ thin films were deposited on Si substrate($SiO_2$ layer of 300 nm thickness was formed on Si wafer via thermal oxidation process), quartz substrate by RF magnetron sputter system for 60 minutes at $500^{\circ}C$ with different RF powers. The surface morphology of as-deposited $VO_x$ thin films was characterized by field-emission scanning electron microscopy. The crystallographic property was confirmed by Raman spectroscopy. The optical properties were characterized by UV-visible spectrophotometer. The coin cell lithium-ion battery of CR2032 was fabricated with cathode material of $VO_x$ thin films on Cu foil. Electrochemical property of the coin cell was investigated by electrochemical analyzer. As the results, as increased of RF power, grain size of as-deposited $VO_x$ thin films was increased. As-deposited thin films exhibit $VO_2$ phase with RF power of 200 W above. The transmittance of as-deposited $VO_x$ films exhibits different values for different crystalline phase. The cyclic performance of $VO_x$ films exhibits higher values for large surface area and mixed crystalline phase.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.396-399
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• 2002

Intense quasi-monochromatic x-ray irradiation from the linear plasma target is described. The plasma x-ray generator employs a high-voltage power supply, a low-impedance coaxial transmission line, a high-voltage condenser with a capacity of about 200 nF, a turbo-molecular pump, a thyristor pulse generator as a trigger device, and a flash x-ray tube. The high-voltage main condenser is charged up to 55 kV by the power supply, and the electric charges in the condenser are discharged to the tube after triggering the cathode electrode. The x-ray tube is of a demountable triode that is connected to the turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to the molybdenum target by the electric field in the tube, the weakly ionized plasma, which consists of metal ions and electrons, forms by the target evaporating. In the present work, the peak tube voltage was almost equal to the initial charging voltage of the main condenser, and the peak current was about 20 kA with a charging voltage of 55 kV. When the charging voltage was increased, the linear plasma x-ray source grew, and the characteristic x-ray intensities of K-series lines increased. The quite sharp lines such as hard x-ray lasers were clearly observed. The quasi-monochromatic radiography was performed by a new film-less computed radiography system.