• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.5
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• pp.44-51
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• 2008

UV lamp systems have been used for cleaning of display panels of TFT LCD or Plasma Display Panel (PDP). However, the needs for high efficient cleaning and low cost made high voltage plasma cleaning techniques to be developed and to be improved. Dielectric-Barrier Discharges (DBDs), also referred to as barrier discharges or silent discharges have been exclusively related to ozone generation for a long time. In this paper, a 6kW high voltage plasma power supply system was developed for LCD cleaning. The 3-phase input voltage is rectified and then inverter system is used to make a high frequency pulse train, which is rectified after passing through a high-power transformer. Finally, hi-directional high voltage pulse switching circuits are used to generate the high voltage plasma. Some experimental results showed the usefulness of atmospheric plasma for LCD panel cleaning.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.36-44
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• 2010

The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1401-1403
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• 1995

This paper investigates the light output characteristics of an electrodeless H-discharge lamp. The existing cylindrical fluorescent lamps were wound around with an induction coil of varying size, and were driven by RF power. The light output and the luminous efficacy were measured according to variations of the induction coil gap and the lamp power, respectively. The experimental results show that the luminous efficacy of the lamp is as much as existing electrodeless lamps and the luminous efficacy of lamps are high between 10W and 20W. Theoretical analyses using computer simulation show that the circuit matching is easier in the external coil configuration than in the internal one, and that the current and the power distributions near the coil are shower in t.

• Journal of the Korea Safety Management & Science
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• v.10 no.2
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• pp.53-60
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• 2008

A test was conducted using two high density discharge lamps, the H2D and the structurally new H4D. They were tested for luminous illumination and luminous temperature in the day and night time. The test was conducted without crippling the performance of the H2D by adding a magnetic actuator, enabling it to move left to right, and up and down. By making these modifications we constructed a sample of the H4D. We compared the H2D and the H4D sample's luminous illumination and luminous temperature by using a photometer and a digital thermometer in the day and night time. We discovered that the H2D and H4D performed similarly from the data we gathered. Now we know the H4D has potential use and extensive research needs to be made to gather more detailed data.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.200-202
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• 2006

A impedance model simulating the electrical characteristics of the Electrodeless fluorescent lamp operated at high frequency is proposed. The model is constructed from a two parameter equation which is derived based on a set of two measurements. This is a readily constructed and computer simulator oriented model which is suitable for a preliminary design of electronic ballasts. Simulated and experimental results are used to verify the analytical discussions, and moreover, an electronic ballast design example using the proposed model is presented to further demonstrate ist applications.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.191-196
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• 2002

In this paper we introduce novel electrode structure for high efficiency discharge. We operate discharge tube under the 0.16 torr pure Xe and apply the sinusoidal wave power to the lamp with 60kHz. We measure the electric power dissipation, plasma parameters, and 828 nm IR intensity. From these data we determine the discharge efficiency, IR intensity/watt, EEDF(Electron energy distribution function). As a result we obtain that the novel electrode structure has better performance in efficiency than that of conventional external electrode system. Also we determine the EEDF for each type of electrode structure by Boltzmann stover, EELNDIF code. The result of Boltzmann equation solving show that the noble electrode system has many high energy electrons compared with the conventional system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.214-220
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• 2010

This paper presents the results of a study on an electrodeless high intensity discharge (HID) lamp system that is powered by circularly polarized microwaves (CPMs). The technique to generate CPMs enables an electrodeless high intensity discharge lamp to be turned on without the retation of the bulb but conventional electrodeless high intensity discharge lamps use rotating bulbs in order to prevent a puncture in a hot spots that are formed by the linearly polarized microwaves in the circular cavity. The technique to generate CPMs is described and the salient features of the lamp characteristics are presented.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1623_1624
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• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp’s properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.11
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• pp.495-502
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• 1986

The change of the discharge characteristics of the high-pressure sodium (HPS) lamps is investigated over a power source frequency range of 60 Hz to 30, 000 Hz. As the frequency increases, the light and electrical characteristics of the HPS lamps are improved since the re-ignition is not needed due to the constant electron density, and the cathode fall is reduced. But at the certain frequency range, the arc instability called acoustic resonance occurs, and the arc tube is damaged. Regarding these characteristics and the kind of the illuminating system, a proper frequency is selected to operate the HPS lamps. And a new measuring system using a computer and the storage-scope is developed to avoid the error of the ordinary gauges at high frequency power.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.142-143
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• 2000

레이저는 입력을 증가시킴에 따라 레이저의 꺼짐 상태에서 레이저의 켜짐 상태로 전이한다. 그러나 그 전이 현상에 대해서는 아직 밝혀진 바가 없다. 이때까지 이 현상은 처음 자발전이의 빛이 점점 유도전이로 바뀌며 그 빛이 점점 세어져 레이저의 출력이 생기기 시작하고 이것이 레이저 입력의 증가에 따라 연속적으로 발전하는 것으로 알려져 왔다. 그러나 이러한 결과에 반대되는 결과들이 최근 밝혀지고 있다[1-2]. 그것은 이산화탄소 레이저에서 이득을 변조시키면 방전이 불안정해지고 그 결과 레이저의 출력도 불안정해 지는데 특히 발진 문턱 근처에서 레이저의 출력은 불규칙 적으로 레이저의 출력이 사라지는 현상이 생긴다는 것이다[1]. 또 다른 하나는 cw Nd:YAG 레이저를 아크 램프로 여기시켜 발진시키면 발진 문턱 근처에서 이 레이저의 출력도 불규칙적으로 레이저의 출력이 사라지는 것으로 나타난다[2]. 이 현상은 레이저의 입력을 증가시킴에 따라 레이저의 꺼짐 상태에서 발진 상태로 전이할 때 그 중간에 불규칙적인 레이저의 꺼짐 상태가 존재한다는 것이 된다. 이 현상이 비선형 동력학의 특이한 현상 중의 하나인 on-off 간헐성임[3]이 밝혀졌다. (중략)