• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.732-735
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• 2009

In this paper, high Xe(Ne+Xe 10%, 20%, 30%) AC-PDP's discharge characteristics according to aging time were studied. The static margin, Vt close curve, discharge time lag was measured for experiments. According to increase of Xe partial pressure, the static margin and luminance was increased. As the result of analysis for misfiring probability, the misfiring is frequently occurred in accordance with increasing of aging time. To improve misfiring, we proposed 3Reset waveform and achieved misfiring probability which was improved.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.687-690
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• 2009

It has been recently reported that nano-sized MgO single crystal powders emit ultraviolet by stimulation of electrons under vacuum condition. Therefore, in this study, nano-crystalline MgO powders were applied to a xenon plasma flat fluorescent lamp for LCD backlight to improve emission efficiency of the lamp by help of extra ultraviolet from nano-MgO. For comparison with nano-crystalline MgO powders, MgO nano-thin film was applied directly on phosphors inside a lamp panel through e-beam evaporation The luminance and efficiency of FFL with an addition of MgO nano-crystal powders on phosphors were improved by around 20%. Application of MgO thin film to phosphors worsened the emission characteristics of FFLs, even rather than FFL without MgO. The reason came from insufficient stimulation of phosphors by UV, crystallinity of MgO, and low secondary electron coefficient.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1511-1514
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• 2009

Organic light emitting layer in OLED device was formed by gravure printing process in this work. Organic surface coated by gravure printing typically showed relatively bad uniformity. Thickness and roughness control was characterized by applying various mixed solvents in this work. Poly (N-vinyl carbazole) (PVK) and fact-tris(2-phenylpyridine)iridium($Ir(ppy)_3$) are host dopant system materials. PVK was used as a host and Ir(ppy)3 as green-emitting dopant. To luminance efficiency of the plasma treatment on etched ITO glass and then PEDOT:PSS spin coated. The device layer structure of OLED devices is as follow Glass/ITO/PEDOT:PSS/PVK+Ir(ppy)3-Active layer /LiF/Al. It was printed by gravure printing technology for polymer light emitting diode (PLED). To control the thickness multi-printing technique was applied. As the number of the printing was increased the thickness enhancement was increased. To control the roughness of organic layer film, thermal annealing process was applied. The annealing temperature was varied from room temperature, $40^{\circ}C$, $80^{\circ}C$, to $120^{\circ}C$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.5
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• pp.239-244
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• 2006

To drive the high-image quality plasma displays of XGA and/or full-HD, we must effectively improve the driving waveform, which get the reset period for the stabilized control of wall charges, the address period to select discharge or non-discharge, and sustain period for luminance in 1 TV-frame, and also the display quality. To accomplish them, the development of the technology for the fast address discharge is required. In this paper, the correlation between the sustain-electrode gap and address discharge characteristics for the high-speed addressing was analyzed using the measurements of dynamic voltage margins. Results showed that the narrower the gap between the sustain electrodes, the narrower the with of the scan pulse became and a dynamic margin of data voltage of 29.2 V was obtained at scan pulse width of $1.0{\mu}s\;and\;V_{ramp}$ of 240 V for driving 4-inch test penal, which the gap between sustain electrodes was $65{\mu}m$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.25-30
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• 2004

In this paper, we suggest a new front panel structure with ridged front panel dielectric layer and hollow gap. The proposed structure can decrease a driving voltage and increase Xe content due to strong electric fields. In the experiment, we have used 6" test panel with 10 %, 15 %, 20 %, 30 % and 50 % Xe contents and 450 torr gas pressure. When comparing with a conventional structure in Xe 10 %, the proposed structure with same Xe content decreased a firing and sustain voltage by about 74 V and 79 V, also the luminance and luminous efficacy of proposed structure with 50 % Xe content were improved by about 33 % and 50.9 %..9 %.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.4
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• pp.53-61
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• 1996

A distribution photometer was constructed to measure the angular distribution of luminous intensity of light sources and the reflected luminance of retroreflectors. This system incorporates a goniometer to rotate test light source(360 degree in yaw rotation and $\pm$30 degree in pictch rotation), a photomultiplier tube as light detector, light projector for retroreflection measurements, and the control and display unit. The ranges of luminous Intensity measurements and observation angles are 0.01~199900 cd and 0.2~1.5 degree respectively. The uncertainty of luminous intensity measurements is $\pm$3%. This paper describes the construction of the distribution photometer and the performance characteristics.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2018-2019
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• 2007

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely $Zn(HPB)_2$ and Zn(HPB)q, which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and Zn(HPB)q. The fundamental structures of the white OLEDs were ITO / NPB (40 nm) / $Zn(HPB)_2$ (40 nm) / Zn(HPB)q (20 nm) / LiAl (120nm). As a result, we obtained a maximum luminance of $15325cd/m^2$ at a current density of $997\;mA/cm^2$. The CIE (Commission International de l'Eclairage) coordinates are (0.28, 0.35) at an applied voltage of 9.75 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.447-450
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• 2003

In this paper, new luminescent material, 6,11-dihydoxy-5,12-naphtacene-dione Alq3 complex (Alq2-Ncd), 1,4-dihydoxy-5,8-naphtaquinone Alq3 complex(Alq2-Nq) was synthesized. And extended efforts had been made to obtain high-performance electroluminescent(EL) devices, since the first report of organic light-emitting diodes(OLEDS) based on tris-(8-hydroxyquinoline) aluminum(Alq3). We have performed investigate characterization of the materials. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured by Flat Panel Display Analysis System(Model 200-AT) at room temperature. An intensive research is going on to improve the device efficiency using the hole injection layer, different electrodes, and etc. By using the hole injection layer, the charge-injection can be controlled and the stability could be improved. This study indicates not only the sterical effect but also some other effects would be responsible for the change of the emission wavelength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.447-448
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• 2005

Recently, organic light emitting diodes(OLEDs) is widely used as one of the information display techniques. We synthesized 2-(2-hydroxyphenyl)benzoxazole($Zn(HPB)_2$). We studied the luminescent properties of OLEDs using $Zn(HPB)_2$. The ionization potential(IP) and the electron affinity(EA) of $Zn(HPB)_2$ investigated using cyclic-voltammetry(C-V). The JP, EA and Eg were 6.5eV, 3.0eV and 3.5eV, respectively. The PL and EL spectra of $Zn(HPB)_2$ were observed at the wavelength of 4S0nm. We used $Zn(HPB)_2$ as an emitting layer and hole blocking layer. At the experiment about hole blocking effect, we inserted $Zn(HPB)_2$ between emitting material layer(EML) and cathode, and hole transport layer(HTL) and emitting material layer(EML). We measured current density-voltage and luminance-voltage characteristics at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.438-440
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• 2005

At present, characteristic of high color reproduction for LCD TV is needed in Display market according to start mass production of LCD TV. Therefore development target for LCD is focused on improvement of color reproduction. The improving methods of high color reproduction are alteration of color Filter or Red, Green, Blue phosphor alteration of CCFL. But decrease of luminance and panel transmittance is caused by alteration of Color Filter. Accordingly, we completed LCD with high color reproduction by the most suitable emission spectrum of CCFL phosphor at panel with conventional color filter. In this experiment, we knew that LCD applied to CCFL with high color rendering characteristic had color reproduction range of 81% compared with NTSC in CIE color coordinate. According to increase of intensity peak and alteration of Red, Green, Blue phosphor spectrum, we made LCD with high color reproduction characteristic. In conclusion we achieved improvement of color reproduction ratio by alteration of CCFL phosphor without changing color filter.