• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4483-4488
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. Driving current of power LED has to be controlled below the designed value. In this paper, half-bridge LLC series resonant converter, which has the current limiting function, has been described. Half-bridge LLC series resonant converter allows in relatively wide input voltage and output load range when compared to the other resonant converter. Also, it is possible to reduce a magnetic component, because leakage inductance of transformer is used as a resonant inductance. It has been validated by designing and testing 200[W] half-bridge LLC converter of DC24[V] output voltage for LED lamp driver, which includes a current limiting function and power factor correction(PFC) function.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.137-138
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• 2015

본 논문은 알루미늄 재질로 된 방열판을 LED조명기구에 적용해서 열 해석을 한 것으로서, PCB에 25[W]급 LED를 배치하여 COMSOL Multi-physics로 시뮬레이션 하였다. 그 결과 LED와 PCB 경계면의 온도는 $69^{\circ}C$이고, PCB바닥면의 온도는 $28^{\circ}C$로 실제작한 FR-4 재질의 LED Module과 근접한 온도임을 확인 할 수 있었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.15-21
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• 2004

The optical characteristics; luminous flux, correlated color temperature, and CIE -chromaticity coordinate etc., of HB LED(high brightness light emitting diode) of yellow/green/white SMD(surface mounted device) type were tested with integrating sphere photometer and monochromator, and the results were comparatively evaluated And, for the white LED, color rendering indices were considered to analyze.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2247_2248
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• 2009

20W급 LED 형광등 광학 설계를 위하여 1W ${\times}$ 20개와 2W ${\times}$ 10개의 두 가지 경우로 Photopia를 이용하여 시뮬레이션 하였다. 이를 통하여 배광곡선, 조도분포, 균제도를 분석하였으며, 그 결과 배광 분포는 1W ${\times}$ 20개가 균일하며, 경제성은 2W ${\times}$ 10개가 우수함을 확인 할 수 있었다.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.319-327
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• 2023

To harvest marketable cucumbers, high quality seedlings must be used. Producing seedlings in the greenhouse during the low radiation period decreases marketability due to insufficient light for growth. Supplemental lighting with artificial light of different quality can be used to improve low light conditions and produce high quality seedlings. Therefore, this study was conducted to select the appropriate supplemental light sources on the growth and seedling quality of grafted cucumber seedlings during the low radiation period. Three cultivars of cucumber were used as scions for grafting; 'NakWonSeongcheongjang', 'Sinsedae', and 'Goodmorning baekdadagi'. Figleaf gourd (Cucurbita ficifolia) 'Heukjong' was used as the rootstock. The seeds were sown on January 26, 2023, and grafted on February 9, 2023. After graft-taking, cucumbers in plug trays were treated with RB light-emitting diodes (LED, red and blue LED, red:blue = 8:2), W LED (white LED, R:G:B = 5:3:2), and HPS (high-pressure sodium lamp), respectively. Non-treatment was used as the control. Supplemental lighting was applied 2 hours before sunrise and 2 hours after sunset for 19 days. The stem diameter and fresh and dry weights of roots did not differ significantly by supplemental light sources. The plant height and hypocotyl length were decreased in W LED. However, the leaf length, leaf width, leaf area, and fresh and dry weights of shoots were the highest in the RB LED. Seedling qualities such as crop growth rate, net assimilation rate, and compactness were also increased in RB LED and W LED. After transplanting, most of the growth was not significant, but early yield of cucumber was higher in LED than non-treatment. In conclusion, using RB LED, W LED for supplemental light source during low radiation period in grafted cucumber seedlings improved growth, seedling quality, and early yield of cucumber.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.161-164
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• 2008

ELS(Edge Light System)을 이용한 40W조명 시스템을 개발하기 위하여, ELS에 적합한 LED를 선정하고, 색온도 제어라 광색제어를 위한 구동회로 및 제어회를 설계 제각 하였으며, 0.5W R,G,B 4 IN 1 Package 를 적용하여 LED 180EA를 사용하여 LED Lighting System을 개발하였다. ELS LED Lighting System은 40W급 LED SMPS 구동회로 및 광색/색온도 제어회로 설계, 면발광을 위한 ELS 설계, 방열 설계 및 기구 구조 설계를 통하여 개발되었으며, 직접 시제품을 제작하고 그 성능을 측정하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.561-566
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• 2014

The high power COB(Chip on Board) LED, densely arranged chips on a board, are increasing to resolve heat problems in LED that has luminous semiconductor chips as main materials. In case of high-power COB LED, protection against heat is necessary due to the power consumption is high. Also if the temperature of device increases, the optical emission becomes less efficient and the life rapidly reduces due to thermal stress. This study packaged 13.5W COB LED and heat sink with difference form and produced 13.5W COB LED down-light heat sink by analyzing the thermal modes with Solidworks Flow Simulation. And finally it analyzed and evaluated the thermal modes using contacting and non-contacting thermometers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.10-18
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• 2011

In order to develop highly-integrated RGBY(Red, Green, Blue, Yellow) LED light, a high thermal radiation ceramic package was manufactured, and the encapsulation process was applied with a vacuum printing encapsulation system(VPES). After the completion of vacuum printing, the shape of the encapsulation layer could be controlled by heat treatment during the curing process, and the optical power became highly increased as the encapsulation layer approached a dome shape. The optical characteristics involved in a Correlated Color Temperature(CCT), a Color Rendering Index (CRI), and the efficiency of RGBY LED light were able to be identified by the experimental designing method. Regarding the characteristics of the white light of RGBY LED light, which were measured on the basis of the aforementioned optical characteristics, CRI posted 88, CCT recorded 5,720[$^{\circ}K$], and efficiency exhibited 52[lm/W]. The chip temperature of RGBY LEDs was below 55[$^{\circ}C$] when the consumption power of LED chips was 0.1[W] for the red, 0.3[W] for the green, 0.08[W] for the blue, and 0.24[W] for the yellow. Also, the thermal resistance of the highly-integrated RGBY LED light measured by T3Ster was 2.3[K/W].

• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.138-144
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• 2010

Optical analysis is necessary to optimize light emitting diode (LED) safety street lighting. In this study, optical analysis was conducted for 100 W LED safety street lighting. Experimental research on such a single LED was the first undertaken. Simulation modeling based on the optical properties of the single LED has compared between average road illuminances and has them analyzed with Korean Industrial Standards for LED safety street lighting (KS C7658:2009). The simulation results demonstrated that the illumination performance (average road illuminance) was 75.3 lx at a height of 4 m and an area of $32\;m^2$, 45.25 lx at a height of 5 m and an area of $72\;m^2$, and 30.05 lx at a height of 6 m and an area of $128\;m^2$. 100 W safety street lighting (model CE180-ST-OS) designed by simulation was also compared between product and 100 W simulation modeling, and error rates averaged 5.6%. The 100 W LED safety street lighting base designed in simulation modeling was proven by comparison experiments. Through the simulations and the corresponding analysis, it was found that the tested 100 W LED safety street lamp had reasonable performance. The design method for LED safety street lamps has been summarized based on the optical analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.1-9
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• 2008

This paper is about l00[W] discrete LED floodlight lighting system, light color and color temperature to be controlled using the 3[W] RGBA LED, is developed the product with optical, heat dissipation, circuit, luminaire and system design. The result, color temperature is changed corresponding to black body locus from 2,000[K] to 10,000[K] and The Color Rendering Index(C.R.I) is achieved from 71 to 91 by high C.RI. Driving voltage is $90{\sim}250[Vac]$, circuit efficiency is 87[%], P.F is more than 93. moreover the LED lens is designed to achieve narrow, middle, wide beam angle, heat dissipation design is executed to minimize variation of luminous output by the surroundings temperature and to ensure reliability.