• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.740-743
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• 2009

In this paper we proposed a new electrode design to get an enhanced luminous efficiency in AC PDP. The width and shape of the TTO electrode were varied, and the electro-optical properties such as luminance, power consumption, luminous efficiency were estimated with the variation of frequency, duty ratio and applied voltage. The discharge characteristics were investigated to explain the effect of the new electrode structure on the electro-optical properties.

• 대한기계학회논문집B
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• 제20권3호
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• pp.1050-1060
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• 1996

Recently, attention has been paid to the flame diagnostic by noncontact methods which dose not deform the flame shape. One of them is a method which is using the radical luminous intensity. Generally, this diagnostic method using radical luminous has been investigated its reliability by applying to laminar flame. This study, however, investigated each radical luminous signals through stocastical analysis like auto-correlation, cross-correlation, phase and coherence which were acquired from measuring radical luminous intensity of OH, CH, $O_{2}$, radicals in turbulent diffusion flame. To compare radical luminous intensity in flame with temperature, ion current and concentration , radious distribution of each properties was investigated and considered. In radical luminous intensity, correlation in the reaction zone of flame was higher than in correlation in combusted gas zone. And radious distribution of radical luminous intensity was corresponded with radious distribution of temperature, ion current and concentration. The result of the study confirms that a radical luminous flame diagnosis is possible in the turbulent diffusion flame.

• Journal of Information Display
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• 제10권3호
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• pp.97-100
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• 2009

A backlight unit for a 42-inch LCD TV was manufactured with red, green, and blue LED lamps. The luminous and light extraction efficiencies of the LED lamps were increased by improving their light reflection structures and thermal properties. The blue, green, and red LED lamps showed different luminous efficiencies as a function of the input current. Compared to the conventional red LED lamp, however, the developed red LED lamp showed very high luminous efficiency in a low drive current. Taking these luminous efficiencies into account, the fabricated backlight unit showed high energy efficiency, low power consumption, and a wide color gamut.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.22-26
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• 2013

The author analyzes the luminous efficiency of the phosphor-conversion white light-emitting diode (LED) that consists of a blue LED chip and a yellow phosphor. A theoretical model is derived to find the relation between luminous efficiency (LE) of a white LED, wall-plug efficiency (WPE) of a blue LED chip, and the phosphor absorption ratio of blue light. The presented model enables to obtain the theoretical limit of LE and the lower bound of WPE. When the efficiency model is applied to the measured results of a phosphor-conversion white LED, the limit theoretical value of LE is obtained to be 261 lm/W. In addition, for LE of 88 lm/W at 350 mA, the lower bound of WPE in the blue LED chip is found to be ~34%. The phosphor absorption ratio of blue light was found to have an important role in optimizing the luminous efficiency and colorimetric properties of phosphor-conversion white LEDs.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.123-127
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• 2011

To clarify the relations of optical properties to the main factors responsible for the loss and damage of luminous efficacy, a 20 min turn-on/turn-off test for 2,000 h for a ceramic metal halide lamp is conducted. The corrosion rates of the arc tube wall and electrode are estimated based on thermal stress. Wall blackening is attributed to the tungsten being transported from the hot electrode tips to the relatively cold arc tube wall. Furthermore, the grain boundaries of the arc tube are changed by the degradation. Distortion of the electrode is observed, and the ignition and the driving voltage of the load both increase. Finally, the color rendering index and the color coordinates are changed after the degradation. The luminous flux and the intensity of the luminous distribution are decreased significantly.

• 전기학회논문지
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• 제58권12호
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• pp.2441-2445
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• 2009

The effects of Si -doped MgO have been investigated in order to improve the material properties of the MgO protective layer in plasma display panels. A small amount of Si is added to the MgO pellet while the MgO layer is being deposited by using an electron-beam evaporation method. Both the surface characteristics of the protecting layer and the electro-optical properties of 4 in. test panels are investigated, such as XRD patterns, SEM images, firing and sustain voltages, secondary electron emission coefficient($\gamma$), luminance, luminous efficacy and lifetime. The firing and sustain voltage are minimized when Si concentration is 0.038%, where the luminance and luminous efficacy increase up to 17% and 26% compared with that of the pure MgO film, separately, and lifetime also shows good characteristics.

• 한국전기전자재료학회논문지
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• 제16권5호
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• pp.409-417
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• 2003

We have studied electrical properties and luminous efficiency of organic light-emitting diodes(OLEDs) with different buffer layer and cathodes in a temperature range of 10 K and 300 K. Four different device structures were made. The OLEDs are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris(8-hydroxyquinolinato) aluminum(III) (Alq$_3$) as an electron transport and omissive layer, and poly(3,4-ethylenedioxythiophene) :poly (styrenesulfonate) (PEDOT:PSS ) as a buffer layer. And LiAl was used as a cathode. Among the devices, the ITO/PEDOT:PSS/TPD/Alq$_3$/LiAl structure has a low energy-barrier height for charge injection and show a good luminous efficiency. We have got a highly efficient and low-voltage operating device using the conductive PEDOT:PSS and low work-function LiAl. From current-voltage characteristics with temperature variation, conduction mechanisms are explained SCLC (space charge limited current) and tunneling one. We have also studied energy barrier height and luminous efficiency at various temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1161-1164
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• 2005

A Mercury-free, flat light source which shows high luminance and luminous efficiency simultaneously has been developed. An electrodeless, dielectric barrier discharge is used to generate the plasma using Ne-Xe mixture gas of relatively low gas pressure of a few tens torr in a 4.1 inch diagonal size of flat panel. The basic properties of the long gap glow discharge and its accompanying instabilities, which prevents us from having high luminous efficiency discharge have been analyzed. A new structure and optimized driving methods have been used to generate a glow discharge which shows a wide voltage margin of a few hundred volts. The luminous efficiency and luminance could be 110 lm/W at $1300\;cd/m^2$ and 50 lm/W at $5500\;cd/m^2$.

• 한국결정학회지
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• 제13권2호
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• pp.63-68
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• 2002

PDP(Plasma Display Panel)에 적용하고자 하는 녹색 형광체 Zn/sub 2-x/Mn/sub x/SiO/sub 4/를 고상반응법으로 제작하였다. 소성온도, 열처리분위기의 수소와 질소가스의 비 그리고 Mn의 첨가제 및 co-dopant가 형광체의 특성에 미치는 영향에 대하여 관찰하였다. Mn의 농도 x=0.002로 하여 소성온도 1400℃에서 발광특성이 가장 우수하였고, co-dopant의 영향에서는 Cr/sup 3＋/를 첨가하였을 때 다른 첨가제를 사용하였을 때 보다 발광특성이 향상되는 것이 관찰되었다.

• 한국지구과학회지
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• 제36권5호
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• pp.427-436
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• 2015

We classified Abell clusters using the magnitude differences between two or three bright member galaxies and investigated how such classification was correlated with the properties of brightest cluster galaxies (BCGs). S-type BCGs being clearly brighter than the rest of the member galaxies were likely to be red, luminous, and evolved as early type galaxies. On the other hand, T-type BCGs being not dominant at all were less luminous than early type galaxies. A small fraction of BCGs was currently forming stars, and all of the star-forming BCGs were T-type BCGs. Active galactic nuclei were most frequent for S-type BCGs. Through these quantitative analyses of the BCG properties, we discussed the possible scenario of BCG formation and the differences between S-type and T-type of BCGs.