• Journal of Power Electronics
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• v.16 no.2
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• pp.815-822
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• 2016

The efficiency of light-emitting diode (LED) devices is a significant factor that reflects the capability of these devices to convert electrical power into optical power. In this study, a method for estimating the efficiency of LED devices is proposed. An efficiency model and a heat power model are established as convenient tools for LED performance evaluation. Such models can aid in the design of LED drivers and in the reliability evaluation of LED devices. The proposed estimation method for the efficiency and heat power of LED devices is verified by experimentally testing two types of commercial LED devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.14-21
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• 2012

This paper study a method of modeling and simulation of LED driver circuit for a design optimization. Simplified LED modeling is introduced and a driver IC, HV9910, is modeled by implementing the major function blocks. Circuit of buck type converter is constructed for simulation. Simulation includes not only the internal function of IC but also the various performance results such as LED array current control and dimming. Experiment results are also shown to prove the verification of its usage. This results show that the simulation approach is valid for a circuit optimization and a reduction of development time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.854-855
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• 2013

최근 국내 전력공급 문제에 따라 다양한 에너지절감형 기술과 제품이 연구되고 있다. 특히 국내 기준 전체 전력 소비량의 약 20%를 차지하는 조명분야에서는 기존 조명을 대체할 친환경, 고효율 LED 조명에 대한 기술이 대두되고 있다. LED 조명은 원리의 특성상 광효율과 비례하여 LED 접합부 온도가 상승하며 이는 광효율과 수명을 저하시킨다. 이에 다양한 방열기술이 LED 조명기술의 핵심이라 할 수 있다. 본 논문에서는 LED 모듈 접합부의 발열을 열전소자를 활용하여 열전발전 함으로써 에너지를 절감하고, 열회수를 통한 방열효과를 제공 하는 LED 조명을 제안한다.

• Transactions on Electrical and Electronic Materials
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• v.9 no.3
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• pp.110-115
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• 2008

In this paper, we have designated a 42-inch RGB LED BLU, 80 % above illuminance. A desirable brightness performance was attained, by doing anti-parallel configuration, a fitting of LED's strip distance and a height of the top of LED to the back of the LCD. We get the 85.81 % of the brightness uniformity which has 12.8 mm away from LED's top and LCD's back and 51.41 mm of the same spacing between LED's strip in simulation and 82.24 % in experiment.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3144-3146
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• 1999

$8{\sim}12$인치의 원형(또는 사각) PCB 기판에 수백 개의 고휘도 반도체 발광 다이오드(Light Emitting Diode. LED)와 구동 회로로 구성되는 LED 교통 신호등은 특정 파장대의 단색광을 발광하므로, 기존의 백열전구식 신호등에 비해 시인성이 좋고, 80 % 이상의 에너지 절약이 가능하다. 그러나 LED는 주위 온도에 따라 밝기가 변화하는 특성이 있다. 신호등은 기능상 외부 온도의 영향 없이 항상 일정한 광도를 유지해야 하므로, 본 논문에서는 외부 온도의 변화에 관계없이 일정한 광출력을 유지할 수 있는 LED 구동회로를 설계한다 이를 위해 정전압 및 정전류로 구동되는 LED의 온도에 따른 광출력 특성 실험이 수행되고, 이러한 데이터들을 바탕으로 정광출력 LED 신호등 구동회로가 설계되고 그 성능을 평가한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.459-460
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• 2006

RGB 3색 LED를 이용 백라이트에서는 백색 광원을 구현을 위해서는 혼색을 위한 충분한 공간 또는 광학계를 필요로 하고 있다. 본 연구에서는 RGB 3색 LED의 컬러 혼색을 위해 광학 설계를 진행을 하였고, 이 광학계는 광경로 변경을 통해 BLU 내부 공간에서 각각의 3색 LED가 충분한 혼색 구간을 확보하여 백색을 구현하게 된다. 최근 적용하고 있는 Side emitting 방식 LED가 아닌 Top view type의 power LED를 이용하여 32인치급 TV LCD 백라이트를 제작하여 최적화를 진행하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1419-1426
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• 2012

The heating and cooling energy load of the KNU plant factory was analyzed using the DesignBuilder. Indoor temperature set-point, LED supplemental lighting schedule, LED heat gain, and type of double skin window were selected as simulation parameters. For the cases without LED supplemental lighting, the proper growth temperature of lettuce $20^{\circ}C$ was selected as indoor temperature set-point together with $15^{\circ}C$ and $25^{\circ}C$. The annual heating and cooling loads which are required to maintain a constant indoor temperature were calculated for all the given temperatures. The cooling load was highest for $15^{\circ}C$ and heating load was highest for $25^{\circ}C$. For the cases with LED supplemental lighting, the heating load was decreased and the cooling load was 6 times higher than the case without LED. In addition, night time lighting schedule gave better result as compared to day time lighting schedule. To investigate the effect of window type on annual energy load, 5 different double skin window types were selected. As the U-value of double skin window decreases, the heating load decreases and the cooling load increases. To optimize the total energy consumption in the plant factory, it is required to set a proper indoor temperature for the selected plantation crop, to select a suitable window type depending on LED heat gain, and to apply passive and active energy saving technology.

• Korean Institute of Interior Design Journal
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• v.21 no.2
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• pp.101-111
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• 2012

The purpose of this study is to draw emotional evaluation model related to LED lighting colors and suggest basic informations that enable planned directions of architectural pacade lighting to simulate beforehand in a laboratory. As experimental methods, extracted PAD emotional evaluation model and then directed a experimental model of 10 LED lighting colors, studied and analyzed survey questions. The results are as follows; First, in the case of P(Pleasure-Unpleasure), Red, Yellow, Green, Cyan, Magenta, White and Combination of $G{\leftrightarrow}B$ Colors are satisfying, vibrant and positive distribution chart has shown. Second, in the case of A(Arousal-Unarousal), Red, Yellow, Green, Cyan, Blue, White and Combinations of $R{\leftrightarrow}G$, $G{\leftrightarrow}B$, $R{\leftrightarrow}B$ Colors, it makes a little difference, they have shown useful distribution chart to induce sight in a aroused state. Third, in the case of D(Dominance-Submissiveness), Red, Cyan, Green and Combinations of $G{\leftrightarrow}B$ Colors are free, controlling and extent of effect was excellent. On the contrary, in the case of Yellow and Magenta and Combinations of $R{\leftrightarrow}B$, they are gentle and arouse the protective instinct or feminine distribution chart has shown. Fourth, it showed difference of preference that difference of select ratios of both men and women in Orange, Blue, Greenish-Yellow (preference of man) and Magenta, Combinations of $R{\leftrightarrow}B$ Colors(preference of woman).

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.984-993
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• 2014

In this paper, we propose a design for an efficient hybrid LED street lighting management system using standalone solar photovoltaic. The proposed efficient hybrid LED street lighting management system was composed of hybrid power conditioning system, gateways, LED street lights and a monitoring server. The hybrid power conditioning system was designed to charge produced power by solar photovoltaic panels in day time, and supply power to the LED street lights in night time. If there is insufficient power, the system was designed to operate using firm power, because the system utilizes photovoltaic power. A system control algorithm allied to the lighting management system, and experimented by being configured to the functions that are able to perform real-time monitoring and remote control through the lighting management system even when absent. In the result of the efficiency analysis of the hybrid lighting management system proposed in this paper, we were able to increase the energy efficiency compared to existing lighting control systems by reducing power consumption and electricity costs.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.448-454
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• 2015

In this paper, the band structural design that is typically in a line was arranged in a ring shape, so as to configure the high power LED lighting in such a way as to form a concentrated light distribution angle of less than 15 degrees. The parabolic aluminized reflector PAR38 that facilitates design using area and the area of the optical system to the same extent, applied a multiple light-source condenser lens optical system for the control of integration. The LED used here implemented a single linear light source using ans LED module with ans LED, flip-chip chip-scale package. The optical system was designed based on the energy star standard.