• Journal of Power Electronics
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• v.9 no.2
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• pp.164-172
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• 2009

Recently, 2-dimensional flat light sources have been attracting much attention for its use in LCD backlight applications because of its high luminous efficiency and uniformity. A long-gap discharge, mercury-tree flat fluorescent lamp has been developed, which shows a high brightness ($>5000\;cd/m^2$) and high luminous efficacy (60 lm/W). Additionally, it has a wide operating margin and stable driving condition with the aid of an auxiliary electrode. For driving the lamp, a narrow pulse power to maintain the glow discharge state is required. Since there has been no research for this kind of lamp driving, this paper proposes a newly developed short-pulse, high-voltage lamp-driving scheme. The proposed lamp system uses a ballast with a coupled-inductor in order to raise the short pulse voltage up to the lamp ignition level and to obtain energy-recovery action during the glow discharge mode. The operation principles are presented and also the system performances such as the lighting efficiency, spatial and angular uniformities are evaluated by hardware experiments. The results show that the proposed lighting system is a good candidate for the next-generation of LCD backlight systems.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.38-41
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• 2002

We have investigated current-voltage-luminance characteristics of organic light-emitting diodes based on TPD/Alq$_3$organics depending on the application of forward-backward bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the current-voltage characteristics were measured. We have observed that the current-voltage characteristics shows a reversible current maxima at low voltage, which is possibly not related to the emission from Alq$_3$. Current-voltage-luminance characteristics imply that the conduction luminance mechanism at low voltage is different from that of high voltage one.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.932-934
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• 2006

A relationship between discharge delay time and the aging method were investigated: A-Y (Address electrode - Scan electrode) aging and conventional X-Y(Common electrode - Scan electrode) aging with the variation of sustain voltage beyond self-erasing discharge. Although A-Y aging decreases discharge delay time, it has several drawbacks like non-uniformity of discharge, degradation of luminous efficiency and a color temperature. In a conventional aging condition which is carried out near the mid-margin voltage, discharge delay time is short in low voltage and high frequency condition. As an alternative to conventional voltage aging, high voltage aging is suggested which is carried out at self-erasing sustain voltage region. High voltage aging shows lower discharge delay time and fast aging speed than conventional voltage aging.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.130-132
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• 2001

We have investigated current-voltage (I-V) characteristics of organic light-emitting diodes based on $TPD/Alq_3$ organics depending on the application of forward-reverse bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the I-V characteristics were measured. We have observed that the I-V characteristics shows a current mxima at low voltage, which is possibly not related to the emission from $Alq_3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.130-132
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• 2001

We have investigated current-voltage(I-V) characteristics of organic light-emitting diodes based on TPD/Alq$_3$ organics depending on the application of forward-reverse bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the I-V characteristics were measured. We have observed that the I-V characteristics shows a current mxima at low voltage, which is possibly not related to the emission from Alq$_3$.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1253-1256
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• 2007

A display device combining plasma display panel (PDP) and field emission display (FED) is proposed to achieve high luminous efficiency. The device can avoid the main energy loss channels of both PDP (ion loss) and FED (low CL efficiency). $2{\sim}6$”-diagonal test panels with carbon nano-tube (CNT) electron emitter and Xenon ambient gas showed the luminous efficiency of 4.14lm/W and brightness of $263cd/m^2$ at 35V (1kHz, 1% duty), indicating that it is a good candidate for the low voltage driven, highly efficient next generation display.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.83-87
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• 2003

One of the most serious problems in AC PDP is low luminous efficiency. One possible candidate for solving such a problem is using high Xe partial pressure. Increase of Xe percentages causes the driving voltage to rise, although brightness is increased. In this study, a new electrode structure is proposed to solve this problem. A test panel fabricated by using new electrode shows improvement of efficiency by 25% and reduction of sustain voltage by 20% compared with the conventional structure.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2169-2171
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• 2005

A new structure is proposed to achieve a low sustaining voltage and high luminous efficacy. By measuring minimum sustaining voltage(Vs) discharge current(Ion), discharge(Ioff), and brightness of the light from a 4-inch ac-PDP, performances of the conventional structure and proposed structure are compared. When compared with the conventional structure, proposed structure showed 6.5% Vsm improvement, 22% luminance improvement and 20% light dispersion improvement at the Ne-Xe(8%) gas mixture of 400 torr.

• Journal of the Korean Vacuum Society
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• v.11 no.2
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• pp.127-134
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• 2002

Recently, Plasma display panel(PDP) has been in the spotlight as one of the next generation flat-panel-display device. The luminance and luminous efficiency improvement is the hot issues for making a plasma display into a large flat panel device. In this paper, We suggest a new penning gas mixture, in order to find the optimum mixture gas in plasma display panel. The optimum gas composition has been found by the partial pressure of inert gases(such as Af and Kr added to matrix of He(70%)-Ne(27%)Xe(3%) and Ne(96%)-Xe(4%)). The influences of Ar or Kr addition to Ne(96%)-Xe(4%) and He(70%)-Ne(27%)-Xe(3%) mixture gases are experimentally investigated for AC Plasma Display Panel. When rare As(0.01%-0.03%) or Kr(0.01%-0.03%) is added Ne-Xe and He-Ne-Xe mixture gases, the luminance increases over 10%-20% and luminous efficiency increases over 10%-20% at 200 Torr. It is sure that luminance and efficiency are improved by Penning effect. Also, This influence of Penning effect is shown by increased wall charge(10%-25%). In addition to the result, firing voltage and minimum sustain voltage was approximately decreased by 2V-3V.

• Korean Journal of Materials Research
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• v.32 no.7
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• pp.320-325
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• 2022

Single OLED and tandem OLED was manufactured to analyze the electroluminescence characteristics of DC driving, AC driving, and full-wave rectification driving. The threshold voltage of OLED was the highest in DC driving, and the lowest in full-wave rectification driving due to an improvement of current injection characteristics. The luminance at a driving voltage lower than 10.5 V (8,534 cd/m²) of single OLED and 20 V (7,377 cd/m²) of a tandem OLED showed that the full-wave rectification drive is higher than that of DC drive. The luminous efficiency of OLED is higher in full-wave rectification driving than in DC driving at low voltage, but decrease at high voltage. The full-wave rectification power source may obtain higher current density, higher luminance, and higher current efficiency than the AC power source. In addition, it was confirmed that the characteristics of AC driving and full-wave rectification driving can be predicted from DC driving characteristics by comparing the measured values and calculated values of AC driving and full-wave rectification driving emission characteristics. From the above results, it can be seen that OLED lighting with improved electroluminescence characteristics compared to DC driving is possible using full-wave rectification driving and tandem OLED.