• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.189-192
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• 2011

A flexible back-light unit (FBLU) is fabricated by embedding plasma discharge clusters in a flexible polymer matrix. The brightness uniformity of an FBLU was measured for various combinations of optical sheets and compared with the simulated results for various bending angles. A gap between light sources causes distinctive integrated brightness curves which have two inflection points depending on bending angle. The brightness distribution of a simulated BLU was in good agreement with that of an actual plasma BLU except for a dark area that appeared at the center of the simulated BLU. The real and simulated BLUs both clearly showed an angle dependency caused by mirror images located between point light sources. On the basis of these results, it is suggested that these mirror-like images could be a major factor in determining the characteristics of FBLUs.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권8호
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• pp.487-494
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• 2000

This paper describes the design, fabrication and experiments of surface-micromachined aluminum micromirror array with hidden pin-joints. Instead of the conventional elastic spring components as connection between mirror plate and supporting structure, we used pin-joint composed of pin and staples to support the mirror plate. The placement of pin-joint under the mirror plate makes large active surface area possible. These flexureless micromirrors are driven by electrostatic force. As the mirror plate has discrete deflection angles, the device can be ap;lied to adaptive optics and digitally-operating optical applications. Four-level metal structural layers and semi-cured photoresist sacrificial layers were used in the fabrication process and sacrificial layers were removed by oxygen plasma ashing. Static characteristics of fabricated samples were measured and compared with modeling results.

• Journal of the Optical Society of Korea
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• 제7권4호
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• pp.230-233
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• 2003

This study describes the conceptual design of a soft x-ray microscope system based on a laserbased source for biomedical application with high resolution (${\leq}$50nm). The laboratory scale soft x-ray microscope consists of high power laser plasma x-ray source and grazing incidence mirrors with high reflectivity. The laser plasma source used for developing this system employs Q-switched Nd-YAG pulsed laser. The laser beam is focused on a tantalum (Ta) target. The Wolter type I mirror was used as condenser optics for sample illumination and as objective mirror for focusing on a detector. The fabrication of the Wolter type I mirror was direct internal cutting using ultraprecision DTM. A hydrated biological specimen was put between the two silicon wafers, the center of which was $Si_3N_4$ windows of 100㎚ thickness. The main issues in the future development work are to make a stable, reliable and reproducible x-ray microscope system.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.335-336
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• 2009

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1529-1530
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• 2006

현재 한빛 플라즈마에서 운영되고 있는 전자기 진단장치는 정전탐침, 자장탐침 및 반자성루프 둥이 있다. 정전탐침은 고정식, 이동식, 고속주사방식 세 종류의 진단장치가 개발되어 실험에 이용되어 왔는데 비교적 쉽게 많은 종류의 probe와 다양한 probe tip을 구성할 수 있기 때문에 한빛 장치에서 axial 및 azimuthal 방향으로 전자 온도/밀도 및 그들의 분포를 측정하고 있다. 단일탐침에서 사용되던 RF 보상기술을 삼중탐침에서도 적용시켜 RF 보상 삼중탐침을 개발하였다. 기존의 삼중탐침의 경우에는 DC에 대해서는 높은 임피던스로 외부에 부유되어 있지만 RF의 경우에는 외부와 부유되지 않고 낮음 임피던스로 연결되어있는 경우가 많았다. 하지만 RF보상 삼중탐침의 경우에는 RF의 경우에도 충분히 큰 임피던스로 부유되어 있다. 따라서 보다 왜곡되지 않은 측정을 할 수 있다. RF보상 삼중탐침을 이용하여 한빛 Mirror 플라즈마에서 axial 방향으로 Plasma 변수들의 변화를 관찰하면서 기존의 탐침에서 볼 수 얼던 여러 특성을 관찰할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2004년도 제26회 학술발표회 초록집
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• pp.144-144
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• 2004

• The Korean Journal of Ceramics
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• 제2권4호
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• pp.197-202
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• 1996

The highly oriented diamond particles were deposited on the mirror-polished (100) silicon substrates in the bell-jar type microwave plasma deposition system using a three-step process consisting if carburization, bias-enhanced nucleation and growth. By adjusting the geometry of the substrate and substrate holder, very dense disc-shaped plasma was formed over the substrate when the bias voltage was below -200V. Almsot perfectly oriented diamond films were obtained only in this dense disc-shaped plasma. From the results of the optical emission spectra of the dense disc-shaped plasma, it was found that the concentrations of atomic hydrogen and hydrocarbon radical were increased with negative bias voltage. It was also found that the highly oriented diamonds were deposited in the region, where the intensity ratios of carbonaceous species to atomic hydrogen are saturated.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.501-501
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• 2012

A 2.45 GHz electron cyclotron resonance (ECR) plasma source with a belt magnet assembly configuration (BMC) was developed for hyperthermal neutral beam (HNB) generation. A plasma source for high flux HNB generation should be satisfied with the requirements: low pressure operation, high density, and thin plasma. The ECR plasma source with BMC achieved high density at low operation pressure due to electron confinement enhancement caused by high mirror ratio and drifts in toroidal direction. The 2.45 GHz microwave launcher had a circularly bended WR340 waveguide with slits. The microwave E-field profile induced by the microwave launcher was studied in this paper. The E-field profile was a cups field perpendicular to B-filed at ECR zone. The optimized E-field profile and B-field were found for effective ECR heating.

• 대한전기학회논문지
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• 제45권2호
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• pp.289-293
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• 1996

The basic study on laser triggered lightning was carried out for the active protection of lightning in power transmission system. The lengths of generated plasma channels were simulated numerically for variations of energy and pulse width of CO$_{2}$ laser by Runge-Kutta-Gill method. As results, the effective lengths of plasma channels were 2.3m, 2.67m and 3.4m respectively for energy of 45J, 60J and 100J of CO$_{2}$ laser pulse with pulse width of 50nsec using focusing mirror with focal length of 10m. And also the effects of pulse width of first pulse and tail pulse of CO$_{2}$ laser on the length of plasma channel were examined.

• 한국진공학회지
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• 제18권3호
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• pp.186-196
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• 2009

하이퍼써멀 영역의 에너지 ($1{\sim}100\;eV$), 특히, 50 eV 이하의 에너지를 갖는 높은($10^{16}$ particles/$cm^2\;s$ 이상) 플럭스의 이온빔을 직접 인출하기는 어렵지만, 이온을 중성화한 중성입자빔 경우에는 가능하다. 높은 플럭스의 하이퍼써멀 중성입자빔을 생성하고 효율적으로 수송하기 위해서는 낮은 플라즈마 운전압력(0.3 mTorr 이하)에서도 높은 이온밀도($10^{11}\;cm^{-3}$ 이상)를 유지할 수 있는 대면적 플라즈마 발생원이 요구된다. 이러한 하이퍼써멀 중성입자빔의 생성을 위해 요구되는 플라즈마 발생원을 구현하기 위해서는 자기장에 의한 전자가둠 방식이 도입되어야 하는데, 영구자석을 이용한 다양한 자기장 구조를 갖는 Electron Cyclotron Resonance (ECR) 플라즈마 발생 방식이 하나의 해결 방법이 될 수 있음을 제안하였다. 여기에는 마그네트론 구조를 갖는 자기장을 채택한 평면형 ECR 플라즈마 발생 방식과 원통형 플라즈마 용기 외벽 둘레에 영구자석 어레이를 설치하여 축방향 자기장을 형성하고 용기 중심부에 전자를 가두는 원통형 방식이 있다. 두 경우 모두 기본적으로 mirror field 구조에 의한 전자 가둠을 기반으로 하고 전자의 drift에 의해 더욱 효율적으로 전자를 플라즈마 공간에 가두는 방식을 도입하고 있어서 낮은 운전압력에서도 높은 밀도의 플라즈마를 발생시키고 유지할 수 있다.