• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.609-613
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• 2010

In this paper, we optimized and simulated the heatsink of 75W LED module for street lighting and evaluated the optical properties with the manufactured heatsink. the structure of LED package make simple as chip and heatslug and thermal flow is analyzed by using the FEM(Finite Element Method) with CFdesign V10. Also, we measured the temperature of heatsink and evaluated the optical properties with infrared thermal image camera and integrated sphere system for luminous flux in $1\;[m^3]$ box. As results, Heatsink optimized in 3 mm pin thickness, 6 mm base thickness and 16 number of pin count by using Heatsink-designer and got the results which is the temperature of $47.37\;[^{\circ}C]$ and thermal resistance of $0.48407\;[W/^{\circ}C]$. In thermal flow simulation, the temperature of heatsink decreased from $51.54\;[^{\circ}C]$ to $51.51\;[^{\circ}C]$ and the temperature of heatsink by the time in real measurement decreased from $47.03\;[^{\circ}C]$ to $46.87\;[^{\circ}C]$. Moreover, we improve 0.68 % in the decreased ratio of the luminous flux.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.197-200
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• 2009

주광의 색온도와 일치하는 실내 전반 조명용 60W급 LED 조명제품 개발하기 위하여 실내 주광에 적합한 LED를 선정하고, 색온도, 광색제어를 위한 구동회로 및 제어회로를 설계 제작 하였다. 그리고 1W급 Cool White, Warm White Package LED 총 168 EA를 적용하여 주광의 색온도와 일치하는 실내전반 조명용 LED 조명 System 을 개발하였다. 주광의 색온도와 일치하는 실내 전반용 LED 조명제품은 60W급 LED SMPS 구동회로 및 광색/색온도 제어회로 설계, 면발광을 위한 방열 설계 및 기구 구조 설계를 통하여 개발되었으며, 직접 시제품을 제작하고 그 성능을 측정하였다. 그 결과 회로 효율은 85% 이상, 색온도는 $3,000{\sim}7,000K$에서 실시간으로 제어 가능 하고, 원하는 색온도을 구현 할 수 있도록 하였으며, 발산각 또한 최대 광도의 1/2 기준으로 $100^{\circ}$ 이상을 만족시켰다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1499-1500
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• 2008

최근에 LCD의 후면광원으로 LED를 채용하는 경우가 증가하고 있다. 이러한 LED를 Back Light으로 사용할 경우 일정한 휘도의 유지와 색좌표의 보정은 고급제품의 경우 채용이 증가하고 있다. 본 연구에서는 LCD Monitor용 LED BLU의 CMS(Color Management System)을 개발하기 위하여 1.5W R,G,G,,B가 하나의 PKG에 들어있는 LED를 이용하여 Direct type의 Back Light Unit을 개발하였다. 방열 및 휘도 균일도를 고려하여 LED part를 설계, 개발하였고 LED를 PWM으로 구동하기 위하여 Switching circuit이 포함되는 구동회로 부분을 설계, 개발 하였다. 또한 Color Sensor와 CMS IC를 사용하여 Color를 Control하고 휘도도 컨트롤하는 제어회로 부분도 개발을 하였다. CMS 기능의 제어회로 부분을 개발하기 위하여 MicroController를 사용하였으며 CMS IC와의 통신을 위한 부분도 개발하였다. 이러한 구성을 개발하여 시제품을 직접 제작하였다. 평가를 위하여 성능시험을 실시하였고 광학적인 평가도 시행하였다. 제작된 시제품은 L558 x W359 x H30 으로 하였다. 휘도는 목표휘도를 이루었으며 균일도는 85% 이상이 되었다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.191-196
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• 2016

In order to establish the basic data for the growth of fish in the aquaculture industry, the behavior analysis of rockfish (Sebastes inermis) depending on the temperature and LED lights was conducted. In this study, water temperatures were set from $3^{\circ}C$ to $30^{\circ}C$ were used. One red light (wave length: 622 nm; light power: 811 mW) and one green lights (wave length: 518 nm; light power: 648 mW) were used. Behavior of the rockfish was expressed as average moving distance (AMD) for 1 minutes and a rate of movement. The mean AMD depending on the temperature was 1.0 m and the mean rates of movement was 50%. The mean AMD were 1.5 m, 1.9 m and 0.7 m in the red LED light, green LED light and control condition respectively. The mean rates of movement were 54%, 65% and 45% in the red LED light, green LED light and control condition respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.61-65
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• 2011

Recently, LCD (liquid crystal display) industry is needed to goods of high reliability and wide range temperature condition and it is interested in products for extremely cold condition without failure of light-up. In this experiment, we made the LED backlight unit for Automotive-navigation under the extremely cold condition. And for making this backlight unit, we used to eight side emitting type white LEDs with 3W high power LED. We could know that this backlight unit releases to 18,000 nit in 24W power consumption and start up voltage time is under the 1ms in the ambient temperature at -40.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.315-316
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• 2009

본 논문에서는 1W 급 이상의 고출력 LED 용 패키지로서 세라믹 LTCC 적층 패키지의 방열 특성을 평가하고 열해석 결과와의 차이에 대해 고찰하였다. 특히, 세라믹 패키지의 방열 특성을 향상시키기 위해 Thermal Via와 Heat slug를 LED Chip 하단부에 위치시켰을 때 방열 특성을 평가하기 위해 Transient Thermal Test를 이용하여 각각의 경우에 대한 열저항을 평가하여 방열 특성의 항상 정도를 확인하였으며, 열해석 시뮬레이션을 통해 얻은 결과와 비교하였다. 평가 결과 Heat slug를 배치한 패키지가 열저항이 $8^{\circ}C/W$로서 가장 우수한 특성을 보여주었으며, 열해석 결과와의 차이에 대해서는 광출력으로 방출된 전력을 계산하여 보정함으로써 $1^{\circ}C$ 이하의 편차를 보여주는 결과를 얻을 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1507-1509
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• 2005

LCD(Liquid Crystal Display) products is needed to have high reliability and are produced without harmful material. Because Substitution for CCFL of Light source used to Conventional backlight unit, research is going about product with LED of light source at present. In this experiment, We made the LED backlight unit with high quality for automotivenavigation. This backlight unit has center luminance of 6500 nit at15W power consumption. We adjusted chromaticity by using ten Blue LED and eight side emitting type White LEDs with high power LED from Lumileds company.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.79-83
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• 2016

This research was analyzed thermal characteristics that was appointed disadvantage when smart LED driver ICs was packaged and we applied extracted thermal characteristics for optimal layout design. We confirmed reliability of smart LED driver ICs package without additional heat sink. If the package is not heat sink, we are possible to minimize package. For extracting thermal loss due to overshoot current, we increased driver current by two and three times. As a result of experiment, we obtained 22 mW and 49.5 mW thermal loss. And we obtained optimal data of 350 mA driver current. It is important to distance between power MOSFET and driver ICs. If thhe distance was increased, the temperature of package was decreased. And so we obtained optimal data of 3.7 mm distance between power MOSFET and driver ICs. Finally, we fabricated real package and we analyzed the electrical characteristics. We obtained constant 35 V output voltage and 80% efficiency.

• Transactions of Materials Processing
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• v.20 no.7
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• pp.473-478
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• 2011

In this study, the performance of a thermo siphon type radiator made of copper for LED lighting system was evaluated by using an inverse heat transfer method. Heating experiments and finite element heat transfer analysis were conducted for three different cases. The data obtained from experiments were compared with the analysis results. Based on the data obtained from experiments, the inverse heat transfer method was used in order to evaluate the heat transfer coefficient. First, the heat transfer analysis was conducted for non-vacuum state, without the refrigerant. The evaluated heat transfer coefficient on the radiator surface was 40W/$m^2^{\circ}C$. Second, the heat transfer analysis was conducted for non-vacuum state, with the refrigerant, resulting in the heat transfer coefficient of 95W/$m^2^{\circ}C$. Third, the heat transfer analysis was conducted for vacuum state, with refrigerant. For the third case, the evaluated heat transfer coefficients were 140W/$m^2^{\circ}C$. Third, the heat transfer analysis was conducted for vacuum state, with refrigerant. For the third case, the evaluated heat transfer coefficients were 140W/$m^2^{\circ}C$ for the radiator body, 5W/$m^2^{\circ}C$. Third, the heat transfer analysis was conducted for vacuum state, with refrigerant for the rising position of radiator pipe, 35W/$m^2^{\circ}C$. Third, the heat transfer analysis was conducted for vacuum state, with refrigerant. For the highest position of radiator pipe, and 120W/$m^2^{\circ}C$ for the downturn position of radiator pipe. As a result of inverse heat transfer analysis, it was confirmed that the thermal performance of the current radiator was best in the case of the vacuum state using the refrigerant.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.331-338
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• 2005

The rapid advances in high power light sources and arrays as encountered in incandescent lamps have induced dramatic increases in die heat flux and power consumption at all levels of high power LED packaging. The lifetime of such devices and device arrays is determined by their temperature and thermal transients controlled by the powering and cooling, because they are usually operated under rough environmental conditions. The reliability of packaged electronics strongly depends on the die attach quality, because any void or a small delamination may cause instant temperature increase in the die, leading sooner or later to failure in the operation. Die attach materials have a key role in the thermal management of high power LED packages by providing the low thermal resistance between the heat generating LED chips and the heat dissipating heat slug. In this paper, thermal transient characteristics of die attach in high power LED package have been studied based on the thermal transient analysis using the evaluation of the structure function of the heat flow path. With high power LED packages fabricated by die attach materials such as Ag paste, solder paste and Au/Sn eutectic bonding, we have demonstrated characteristics such as cross-section analysis, shear test and visual inspection after shear test of die attach and how to detect die attach failures and to measure thermal resistance values of die attach in high power LED package. From the structure function oi the thermal transient characteristics, we could know the result that die attach quality of Au/Sn eutectic bonding presented the thermal resistance of about 3.5K/W. It was much better than those of Ag paste and solder paste presented the thermal resistance of about 11.5${\~}$14.2K/W and 4.4${\~}$4.6K/W, respectively.