• 한국전기전자재료학회논문지
• /
• 제32권1호
• /
• pp.40-46
• /
• 2019

To study the frequency response characteristics of alternating-current-driven organic light-emitting diodes (OLEDs), we fabricated blue-fluorescent OLEDs and analyzed their electroluminescent characteristics according to the alternating current voltage and frequency. The luminance-frequency characteristics of alternating-current-driven OLED was similar to that of a low-pass filter, and the luminance of high-voltage OLED decreased at higher frequency than low-voltage OLED. The luminance characteristics of the OLED according to the frequency is due to the capacitive reactance in the OLED, generated during the alternating current driving. The frequency response characteristics of the OLED according to the voltage is due to the decrease in internal resistance of the organic layer. In addition, the negative voltage component of the alternating current did not affect the frequency response of the OLED. Therefore, the electroluminescent characteristics of OLED with an alternating current power of 60 Hz are not influenced by the frequency.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 B
• /
• pp.1211-1213
• /
• 2004

CCFL(cold cathode fluorescent lamp) are used to backlight of LCD(liquid crystal display). CCFL dimming methods are used to pulse frequency modulation(PFM) or pulse width modulation(PWM). In this paper, design of CCFL driving and control circuit by half-bridge type series and parallel resonant inverter that variable frequency modulation method to control the output voltage current. Inverter switching frequency is higher than resonant frequency for stable operating, and it is possible dimming control. On the basis of equivalent circuit, the validity of this study is confirmed by the comparison of simulation and experimental result.

• 한국진공학회지
• /
• 제12권1호
• /
• pp.46-50
• /
• 2003

외부전극 형광램프 12개를 평면에 배치하여 제작한 대각길이 17인치 직하형 백라이트의 구형파 구동에 의한 휘도와 효율 특성을 조사하였다. 구동 전압 1-2 kV와 주파수 40-80 kHz에 대하여 백라이트 패널의 휘도가 5,000-10,000 cd/$\textrm m^2$ 일 때 효율 65-70 1m/W를 얻었다. 구동 주파수가 클수록, 고휘도를 얻고 구동 전압이 낮아진다. 구동 주파수가 80 kHz 이상의 주파수에서는 백라이트의 휘도가 불안정하고, 면전체 휘도의 균일성을 얻지 못한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제54권12호
• /
• pp.601-608
• /
• 2005

This paper presents a novel single-stage high-power-factor electronic ballast for fluorescent lamps operating in critical conduction mode. The proposed topology is based on integration of boost converter as power factor corrector(PFC) and a half-bridge high frequency parallel resonant inverter into a single stage. The input stage of the boost converter is operating in critical conduction mode for positive and negative half cycle voltage respectively at line frequency(60Hz). So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. The simulated and experimental results for 100W fluorescent lamps operating at 42kHz switching frequency and 220V line voltage have been obtained. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, fluorescent lamp and DC-DC converter etc.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.391-394
• /
• 2006

This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제49권6호
• /
• pp.441-449
• /
• 2000

Analysis, design and practical implementation of a single-stage electronic ballast for compact fluorecent lamps are presented in this paper. The proposed topology is based on a single-stage ballast which combines a boost converter and a half-bridge series resonant inverter. High power factor is achieved by using the boost semi-stage operating in discontinuous conduction mode, and inverter semi-stage operated above resonant frequency to provide zero voltage switching is employed to ballast the fluorescent lamp. Analytical and experimental results from the ballast system with 36W fluorescent lamps have demonstrated the feasibility of the proposed single-stage electronic ballast.

• 한국진공학회지
• /
• 제11권1호
• /
• pp.76-80
• /
• 2002

외관 전극의 용량성 결합에 의하여 동작되는 형광램프의 특성을 조사하였다. 외관전극 형광램프는 10 mA 이하의 저전류와 약 1.5 kV의 고전압으로 구동된다. 구동 주파수 100 kHz 이하의 구형파 구동에 의하여 효율 40 lm/W의 20,000~30,000 cd/$\textrm m^2$의 고휘도를 실현하였다. 외관전극의 길이가 길수록 휘도와 효율이 증가하지만, 전극 길이가 3 cm 이상에서 그 증가율이 둔화된다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.132.1-132.1
• /
• 2014

Fluorescent-magnetic nanoclusters were synthesized for biomedical applications. The nanoclusters consisted of superparamagnetic core-nanoclusters, highly fluorescent shell of nanocrystals, and lipid A. Magnetic cores were used for both magnetic resonance imaging (MRI) and cell separation. Fluorescent shell was used for optical imaging. The lipid-A-loaded nanoclusters were up-taken by dendritic cells via phagocytosis, which successfully activated dendritic cells. The dendritic cells were migrated to lymph nodes and spleen of mice. The results showed that our novel nanoclusters can play a role as an efficient optical and magnetic imaging, a cell separating and a pathogen mimetic agent at the same time. Additionally, synthesis of wavelength conversion nanowires will be discussed, which may be used as an optical nanoprobe in biological studies.

• 한국산학기술학회논문지
• /
• 제11권1호
• /
• pp.113-118
• /
• 2010

압전 변압기와 CCFL, 형광등의 전기적 등가회로에 의한 PSPICE 모델을 제시하였고, 차세대 35W급 초절전형 삼파장 T5 형광램프용 고효율 형광등 안정기를 개발하였다. 이 안정기는 역률개선회로와 인버터에 압전 변압기를 채용하여 T5 형광램프의 점등실험을 하였으며, 압전 변압기의 효율적인 구동과 정확한 주파수 공급을 위하여 PLL방식을 사용하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.171-176
• /
• 2004

An electric power efficiency of electrodeless fluorescent lamp has big relative propertye of gas in lamp, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. We used magnetic substance that open self-examination material of electrodeless fluorescent lamp antenna. Ferrite that is used in this experiment was Mn-Zn type. Coill turn was changed from 13th to 15th turn to recognize brightness change of lamp by winding number. Optical equipment that used in an experiment was used to measure brightness (LS-100). When an electrodeless fluorescent lamp was made using and T company's PE22, was it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.