• 전기학회논문지
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• 제65권9호
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• pp.1571-1576
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• 2016

A Tesla coil is an electrical resonant transformer circuit invented by Nikola Tesla in 1891. It is used to produce high-voltage, low-current, high frequency alternating-current electricity. Tesla coil can generate a long streamer with several million volts of electricity as a high voltage device. It is basically consists of a voltage transformer, high voltage capacitor, spark gap, primary coil, secondary coil and toroid. It is difficult to appear in the output size of the streamer is controlled by the spark gap. The general decision method of the length of streamer is to display the electric output in accordance with the design specifications in initial development plan. Design specifications and the electric output is determined by the application of facilities. In this paper the spark gap is replaced with periodic switching semiconductor device to control output voltage easily in order to apply overvoltage protective circuit due to a secondary coil and a performance test. In these days, their main use is for entertainment and educational displays of the museum, although small coils are still used as leak detectors for high vacuum systems.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.371-375
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• 2019

Developing a thin-film transistor with characteristics such as a large area, high mobility, and high reliability are key elements required for the next generation on displays. In this paper, we have investigated the research trends related to improving the reliability of oxide-semiconductor-based thin-film transistors, which are the primary focus of study in the field of optical displays. It has been reported that thermal treatment in a high-pressure oxygen atmosphere reduces the threshold voltage shift from -7.1 V to -1.9 V under NBIS. Additionally, a device with a $SiO_2/Si_3N_4$ dual-structure has a lower threshold voltage (-0.82 V) under NBIS than a single-gate-insulator-based device (-11.6 V). The dual channel structure with different oxygen partial pressures was also confirmed to have a stable threshold voltage under NBIS. These can be considered for further study to improve the NBIS problem.

• 한국의학물리학회지:의학물리
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• 제18권2호
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• pp.98-106
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• 2007

2005년 6월 연세의료원 세브란스병원에서는 진단목적으로 20대의 5 mesa 화소 Totoku ME511L 평판 LCD 표시장치를 추가하여 PACS를 확장하였다. 20대의 Totoku ME511L 표시장치를 대상으로 반사, 휘도 반응, 휘도 공간 의존, 분해능, 잡음, 베일링 그레어, 그리고 색도 항목에 대하여 AAPM TG 18보고서에 기준하여 정량적인(또는 시각적인) 인수검사를 실시하였다. 측정에 사용된 장치는 색도를 측정할 수 있는 만원경식 휘도계, 조도계, 반사 측정에 필요한 빛 선원, 빛 차단 장치, 그리고 TG18 테스트 패턴들이었다. 선택된 8대의 표시장치에 대한 평균 확산 반사계수($R_d$)는 $0.019{\pm}0.02sr^{-1}$이었다. 휘도 반응 검사에서, 휘도비(LR), 최대 휘도 변이($L_{max}$), 그리고 최대 대조도 반응 변이는 각각 $550{\pm}100,\;2.0{\pm}1.9%$, 그리고 $5.8{\pm}1.8%$이었다. 휘도 균일도 검사에서, 최대 휘도 변이는 TG18-UNL10 테스트 패턴의 10% 휘도에 대하여 $14.3{\pm}5.5%$이었다. 분해능 측정은 휘도 측정법으로 수행하였으며 중심에서 퍼센트 휘도(${\Dalta}L$)는 $0.94{\pm}0.64%$이었다. 시각적인 방법의 잡음측정의 모든 경우에서, 중앙 및 주위 4사분면에서 가장 작은 것을 제외하고 15개의 모든 정사각형의 표적을 인식할 수 있었다. 글레어 비(GR)은 $12,346{\pm}1,995$이었다. 최대 색도 균일도 지표(D)는 $0.0025{\pm}0.0008$이었다. 또한 국내 실정에 적합한 진단용 표시장치의 정도관리 가이드라인 연구 결과를 제시하였다. 모든 인수검사 결과는 AAPM TG18 보고서 기준에 포함되어 진단 목적으로 사용하기에 적합하였다. 결론으로 인수검사는 표시장치가 진단에 사용하기에 적합한 성능임을 알려줄 뿐만 아니라 정도관리의 가이드라인, 최적 판독 환경, 그리고 표시장치의 교체시기를 결정하여주는 중요한 역할을 할 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.254-255
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• 2012

Interest in nano-crystalline silicon (nc-Si) thin films has been growing because of their favorable processing conditions for certain electronic devices. In particular, there has been an increase in the use of nc-Si thin films in photovoltaics for large solar cell panels and in thin film transistors for large flat panel displays. One of the most important material properties for these device applications is the macroscopic charge-carrier mobility. Hydrogenated amorphous silicon (a-Si:H) or nc-Si is a basic material in thin film transistors (TFTs). However, a-Si:H based devices have low carrier mobility and bias instability due to their metastable properties. The large number of trap sites and incomplete hydrogen passivation of a-Si:H film produce limited carrier transport. The basic electrical properties, including the carrier mobility and stability, of nc-Si TFTs might be superior to those of a-Si:H thin film. However, typical nc-Si thin films tend to have mobilities similar to a-Si films, although changes in the processing conditions can enhance the mobility. In polycrystalline silicon (poly-Si) thin films, the performance of the devices is strongly influenced by the boundaries between neighboring crystalline grains. These grain boundaries limit the conductance of macroscopic regions comprised of multiple grains. In much of the work on poly-Si thin films, it was shown that the performance of TFTs was largely determined by the number and location of the grain boundaries within the channel. Hence, efforts were made to reduce the total number of grain boundaries by increasing the average grain size. However, even a small number of grain boundaries can significantly reduce the macroscopic charge carrier mobility. The nano-crystalline or polymorphous-Si development for TFT and solar cells have been employed to compensate for disadvantage inherent to a-Si and micro-crystalline silicon (${\mu}$-Si). Recently, a novel process for deposition of nano-crystralline silicon (nc-Si) thin films at room temperature was developed using neutral beam assisted chemical vapor deposition (NBaCVD) with a neutral particle beam (NPB) source, which controls the energy of incident neutral particles in the range of 1~300 eV in order to enhance the atomic activation and crystalline of thin films at room temperature. In previous our experiments, we verified favorable properties of nc-Si thin films for certain electronic devices. During the formation of the nc-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. The more resent work on nc-Si thin film transistors (TFT) was done. We identified the performance of nc-Si TFT active channeal layers. The dependence of the performance of nc-Si TFT on the primary process parameters is explored. Raman, FT-IR and transmission electron microscope (TEM) were used to study the microstructures and the crystalline volume fraction of nc-Si films. The electric properties were investigated on Cr/SiO2/nc-Si metal-oxide-semiconductor (MOS) capacitors.