• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.199-202
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• 2004

CCFL(Cold Cathode Fluorescent Lamp) are used to backlight of LCD(Liquid Crystal Display). This paper presents analysis of half-bridge type resonant inverter of CCFL drive in order to stable characteristics, and fluorescent lamp operation frequency is higher than resonant frequency for safe operation. Besides, The Piezoelectric ceramic transformer (PZT) is electro-mechanical device that transfers electrical energy through a mechanical vibration. The modified equivalent circuit model of the PZT considering the operating current level is derived to design the CCFL. The validity of this study was confirmed from the simulation and experiential result.

• 전력전자학회논문지
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• 제15권1호
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• pp.52-59
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• 2010

기존의 LCD-TV의 백라이트 모듈로 사용되는 CCFL(Cold Cathode fluorescent Lamp:냉 음극형 형광램프)을 구동 하는 인버터 회로는 3단으로 구성되어 전체 시스템의 효율저하 문제가 발생한다. 본 논문에서 제안된 회로는 DC/DC단을 사용하지 않아 전체 시스템의 효율을 향상 시킬 수 있다. 역률 개선을 위한 PFC(Power Factor Corrector)단의 출력 전압을 인버터의 입력전압으로 사용하여 CCFL을 구동한다. 인버터에서는 4-in-1트랜스포머를 사용하여 CCFL간의 전류평형 및 동시점등을 이룰 수 있으며, 전류평형을 위한 부가회로가 불필요하다. 인버터 시스템을 2단으로 구성하여 회로구성이 간소화되고 회로의 부피 및 제작 원가를 저감 할 수 있다. 제안된 기준에 따라 설계한 인버터를 40인치 LCD-TV용 백라이트 모듈에 적용한 실험결과를 통해 유용성을 검증한다.

• Journal of Information Display
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• 제13권4호
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• pp.167-177
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• 2012

Cold cathode fluorescent lamps (CCFLs) are used to provide lighting for liquid crystal displays (LCDs). This paper presents a set of guidelines for measurement characterization and design to reduce the power consumption of CCFL LCD backlight inverters and panel electronics. The proposed methods aim to reduce the backlight power consumption by fine-tuning a back-light inverter for a specific LCD, using several methods. First, the authors describe their power measurement methodology; and next, they identify different areas for tuning a backlight inverter for a given display. The experiment results showed that power savings can range from 50 to 200mW if the backlight inverter is properly tuned. This paper also proposes an optimized configuration for light-emitting device (LED) panels to reduce power loss by selecting a LED with a specific input voltage and number of cells to help minimize power loss.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.405-407
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• 2005

As the screen size of LCD increases, EEFL(External Electrode Fluorescent Lamp) has been suggested to be applicable as backlight source for LCD . Since the electrodes of EEFL are outside of the tube, EEFL enhances the lifetime compared with CCFL(Cold Cathode Fluorescent Lamp), and a single inverter can drive multiple EEFL tubes of which luminance is uniform Therefore, a compact design can be realized and the cost of EEFL application would be much lower than that of CCFL. Moreover, EEFL inverter has higher efficiency per unit power than CCFL inverter. In this paper, a complementary full-bridge PWM(Pulse Width Modulation) inverter was designed for 32-inch LCD TV backlight which has 20 EEFL tubes and adapted two different driving methods to the EEFL inverter. The validity of this study is confirmed from the experimental results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.428-428
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• 2007

In this study, It was studied about the luminance characteristics of 17inch direct-type back light using EEFL(External Electrode Fluorescent Lamp). EEFI has a long life time because the electrode is installed outside of lamp. And it is produced low price than conventional CCFL. It does not need process of installing internal electrode. But EEFL technology has several problems such as difficulty of design driving inverter, and prevents leckage current along the skin of lamps. Therefore, by the optimizing of inverter properties, 7525 nit center luminance was acquired in almost same power consumption condition. It was almost same luminance in CCFL backlight unit. And it was operated stably in low operating temperature such as the value of $40^{\circ}C$, so that it was adopted in conventional LCD-TV application.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권7호
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• pp.353-361
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• 2006

This paper presents the design scheme of transformer for backlight inverter and discuss the characteristics related to its design, including driving inverter. A few studies have so far been made at design and characteristics analysis of transformer. Therefore, this paper manages the presentation of the advisable design methodology of transformer for backlight inverter supplying CCFL. To verify the proposed method, this paper accomplishes the analysis by FEM coupled with circuit and finally shows that the proposed design method is very useful.

• 정보처리학회논문지B
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• 제17B권6호
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• pp.445-458
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• 2010

LCD 모니터의 백라이트로 CCFL 형광체를 많이 사용하고 있으나 그 불량여부는 육안에 의존하고 있다. 육안 검사를 함으로써 부품에 대한 일관성 있는 검사가 결여되고, 노동집약적인 검사로 인해 산업적 재해가 발생할 수 있다. 따라서, CCFL 불량유무를 자동으로 판별하기 위해서 물리적 촬영 환경과 영상처리 알고리즘은 중요하다. 본 논문에서는 CCFL 형광체를 자동으로 검사하기 위한 촬영환경 중 다섯 가지 조건과 세 가지조건 중 두 조건모두에서 사용되는 측면 촬영환경에서 획득한 영상을 이용하여 불량을 판별하기 위한 알고리즘을 제시하였다. 불량을 포함한 CCFL 형광체와 정상시료를 사용하여 영상 획득 및 실험을 수행하였고, 그 결과 제안한 촬영환경과 알고리즘은 과검율 4.65 %와 유출률 5.37 %의 성능을 보인다.

• Journal of Power Electronics
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• 제7권1호
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• pp.38-43
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• 2007

An External Electrode Fluorescent Lamp (EEFL) has longer lifespan, higher power efficiency and higher luminance than a Cold Cathode Fluorescent Lamp (CCFL). Moreover, it is easy to drive them in parallel. Therefore, the EEFL is expected to quickly replace the CCFL in LCD backlight systems. However, the EEFL has more complex characteristics than the CCFL with a resistive component, because it has both a resistive component by plasma and a capacitive component by external electrode. In this paper, values of resistance and capacitance are measured at several power levels and at several operating frequencies. They are expressed by a numeral formula based on a linear approximation that represents the equivalent resistance and capacitance as a function of power. Then we made block diagram of the equivalent circuit model using numerical expressions. Simulation waveforms and experimental results are presented to verify the feasibility of the equivalent model.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2847-2850
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• 2003

A input voltage conversion dimming control formula and a PMW dimming control formula which have been used for dimming control of CCFL driving inverter in TFT-LCD backlight, are the existing facilities so far, however, in this thesis the circuit is designed by applying The rover inverter that are able to measure output brightness according to changing of duty ratio at PWM and voltage. consequently, it's able to be confirmed that we can have dimming control more detailed than before.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.239-241
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• 2006

본 논문에서는 Liquid crystal display (LCD) Backlight module중에 Cold cathode fluorescent lamp (CCFL)를 포함한 인버터가 가지고 있는 기생 용량 측정 방법을 고안하였다. CCFL의 부성 저항 특성을 고려하여 램프의 정적 저항 성분을 일정하게 유지시키고 입력 전압 대 출력 전압의 비 중 최대 Gain을 갖는 주파수를 찾아내 기생 용량을 계산하는 Algorithm을 완성하였다. 시뮬레이션과 실험 결과를 통해 비교 검증함으로써 측정 방법의 유효성을 입증하였다.