• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.9-17
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• 2011

Development of high efficiency and eco-friendly LED source has been progressed continuously. Also, by nation's regulations, public institutions have changed existing luminaires to LED luminaires. However, there are several differences between existing luminaires and the intensity distribution of general planar LED luminaires. In case of changing existing luminaires to LED luminaires, by such differences, there are inefficiencies both quality aspect and energy aspect in luminous environment. Therefore, this study aims to conduct a study on the changes of intensity distribution and luminous environment by reflector shapes in indirect reflected LED luminaires with software for optical design of a luminaire (Photopia 2.0) and lighting design of a space (ReluxPro). This study shows the changes of intensity distribution and luminous environment of indirect reflected LED luminaires and indirect fluorescent lamp luminaires by reflector shapes.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1221-1224
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• 2005

The improvement of luminance and luminous efficiency is the one of the most important parts in AC-PDPs. To achieve high luminance and luminous efficiency, high VUV emission efficiency is needed. We measured the emission spectra of the vacuum ultraviolet(VUV) rays in surface discharge AC-PDP with ternary gas mixture of He-Ne-Xe. The influence of He-Ne-Xe gas-mixture ratio on excited $Xe^{\ast}$ resonant atoms and $Xe_2\;^{\ast}$ dimers has been investigated. It is found that luminous efficiency of ternary gas mixture, He-Ne-Xe, is shown to be much higher than that of binary gas mixture of Ne-Xe. For improving discharge luminous efficiency, we have studied VUV emission characteristics of ternary gas mixture, He(50%)-Ne-Xe and He(70%)-Ne-Xe with Xe concentration and filling gas pressure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.19-25
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• 2015

The management of energy resources for efficient utilization of the energy resources while reducing the system costs is a critical technical issue. Among many kinds of the energy resource management, the energy reduction for indoor lighting systems is getting much concern as a large portion of energy consumption has been made for indoor lightings. In this paper, an energy-efficient lighting control scheme for indoor lighting systems in order to reduce the energy consumption by controlling the luminous flux and the lighting direction under the illuminance constraints is proposed. With the use of the user location information for the luminaire which is closely located to the user, the proposed scheme firstly sets the light direction of the luminaire to be aligned to the user location. Then, an optimization problem to find the luminous flux of each luminaire is formulated in order to minimize the luminous flux sum of the luminaires with the constraints for the dynamic ragne of the luminous flux, and the light flux for each luminaire is determined by the solution of the problem. Simulation results show that the proposed scheme outperforms the luminaire control scheme with only the luminous flux control in the evaluation of satisfaction of the required illuminance level.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1666-1668
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• 1997

This paper reports the optimal gas mixing ratio for color plasma display panel to improve luminous efficiency using gas dischage simulation which contains energy equation. We verified a simulation by measuring vacuum ultraviolet. The luminous efficiency has improved considerably(about 30%) by adding Ar (0.5%), compared with Ne-Xe(4%) mixing gas.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.142-146
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• 2007

Nowadays, itis inevitable trend to use high Xe gas contents for increase luminous efficiency and luminance in plasma display panel. However, the increase of Xe gas contents causes the driving voltage, although the brightness is increase. In this paper, we study the characteristics of electro optical according to Xe gas contents and gas pressure. Electro-optical characteristics were investigated by the discharge voltage, luminance and luminous efficacy measurements, respectively. With some increasing Xe gas contents and pressure, the electro-optical properties increased. However, the characteristics of electro-optical begin to be saturated, when too high increased Xe gas contents and pressure.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.961-965
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• 2006

White organic LED spectrum for lighting and displaying should be designed for high luminous efficiency as well as good chromaticity coordinate, pleasant correlated color temperature and color rendering. A program based on Matlab was made to make these calculations convenient. The chromaticity coordinate and luminous efficiency was calculated according to the CIE 1931 colorimetric system, while the correlated color temperature(CCT) was calculated based on CIE 1960 UCS diagram. The color rendering characteristics were evaluated according to the CIE Color Rendering Index (CRI), using Ra, Ri and ${\bigtriangleup}E$ from the 14 color samples defined in CIE13.3.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.9
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• pp.400-406
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• 2003

Efficient electrodes are devised for organic luminescent device(OLED). ITO electrode is treated with $O_2$ plasma. In order to inject hole efficiently, there is proposed the shape of anode that inserted plasma polymerized films as buffer layer between anode and organic layer using thiophene monomer. In the case of device inserted the buffer layer by using the plasma polymerization after $O_2$ plasma processing for ITO transparent electrode, since it forms the stable interface and reduce the moving speed of hole, the recombination of hole and electronic are made in the emitting layer. Therefore it realized the device capability of two times in the aspect of luminous efficiency than the device which do not be inserted the buffer layer. Experiments are limited to the device that has the structure of TPD/$AIq_3$, however, the aforementioned electrodes can similarly applied to the organic luminous device and the Polymer luminous device.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1007-1010
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• 2003

We made use of $Alq_3$ which is the representative light-emitting material. Electric conduction mechanism and luminance characteristics were analyzed in this paper. We have also measured current density-thickness-voltage characteristics with thickness variation from 60 to 400nm. we analyzed the low electric and the high electric field in theoretically. Also, maximum luminous efficiency is the thickness 200 nm of $Alq_3$ in luminous-thickness characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.147-147
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• 2015

The multilayer structure of the organic light emitting diode has merits of improving interfacial characteristics and helping carriers inject into emission layer and transport easier. There are many reports to control hole injection from anode electrode by using transition metal oxide as an anode buffer layer, such as V2O5, MoO3, NiO, and Fe3O4. In this study, we apply thin films of LiF which is usually inserted as a thin buffer layer between electron transport layer(ETL) and cathode, as an anode buffer layer to reduce the hole injection barrier height from ITO. The thickness of LiF as an anode buffer layer is tested from 0 nm to 1.0 nm. As shown in the figure 1 and 2, the luminous efficiency versus current density is improved by LiF anode buffer layer, and the threshold voltage is reduced when LiF buffer layer is increased up to 0.6 nm then the device does not work when LiF thickness is close to 1.0 nm As a result, we can confirm that the thin layer of LiF, about 0.6 nm, as an anode buffer reduces the hole injection barrier height from ITO, and this results the improved luminous efficiency. This study shows that LiF can be used as an anode buffer layer for improved hole injection as well as cathode buffer layer.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.149-151
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• 2009

This paper gives a comparative analysis on the luminous efficiency of the bulb type LED lamps. we compare and analyze the measurement values bulb type LED lamps using both photogoniometer and integrating sphere. The volt and watt of one 1map are 220 V and 7 W, respectively. The volt and watt of other one are 100 V and 5.3 W, respectively. the values of those were 79.7 1m/W and 76.9 1m/W in the integrating sphere, respectively. Similarly, the values of those were 80.2 1m/W and 79.3 1m/W on the photogoniometer, respectively. As a result, the value of luminous efficiency can be measured using either integrating sphere or absolute goniometer regardless of the difference in case of bulb type LED lamps.