• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.19-25
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• 2014

In the LED lighting applications, because LED packages are the origin of heat generation, there are thermal design problem on heat sinks. In the thermal design, it is important to consider the total volume and the total weight of heat sink simultaneously. In this study, an Al 6063 heat sink was optimized using Computational Fluid Dynamics(CFD) simulation tool for the cooling of 30W LED module, and then the cooling performance and the total weight of heat sinks with Al 6063 and Thermal Conductive Polycarbonate(TCP) were compared under the same conditions. As the result of simulation, an Al 6063 heat sink was optimized with 22 ea. of fins and 1.6 mm of fin thickness. LED Junction Temperature of the TCP Heat Sink was $5.6^{\circ}C$ higher, but total weight of it was 47 % less than the Al 6063.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.7-12
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• 2007

A SPICE-based 3-dimensional circuit model of LED(Light-Emitting Diode) was developed for the design optimization and analysis of high-brightness LEDs. An LED is represented as an array of pixel LEDs with small preassigned areas, and each of the pixel LEDs is composed of circuit networks representing the thin-film layers(n-metal, n- and p-type semiconductor layers, and p-metal), ohmic contacts, and pn-junctions. Each of the thin-film layers and contact resistances is modeled by a resistance network, and the pn-junction is modeled by a conventional pn-junction diode. It has been found that the simulation results using the model and the corresponding parameters precisely fit the measured LED characteristics.

• International journal of advanced smart convergence
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• v.2 no.2
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• pp.19-22
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• 2013

As the demand of the LED for lighting that emits light by p-n junction is increasing, studies on heatproof plate technology is being conducted to minimize the temperature of the LED lighting. As for the temperature of the LED devices, their light emitting efficiency decreases and the maximum lifespan drops down to 1/5. Therefore there are heat dissipation studies going on to minimize the heat. For LED heat dissipation, aluminum heat sink plates are mostly used. For this paper, we designed heat sink that fits residential 20W COB LED Down Light; packaged the heat sink and 20W COB and analyzed and evaluated the thermal properties through a Solidworks flow simulation. We are planning to design the optimal heat sink plate to solve the thermal agglomeration considering TIM(Thermal Interface material).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.126-129
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• 2001

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.1-3
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• 2002

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed typical I-V characteristics. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.158-163
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• 2013

In this paper, thermal analysis of heatsink for 30 W class Chip-on-Board (COB) LED light source is performed by using SolidWorks Flow Simulation package. In order to increase the convection heat transfer, number of fin and shape of the heatsink is optimized. Furthermore, a copper spread is applied between the COB LED light source and the heatsink to mitigate the heat concentration on the heatsink. With the copper spread, the junction temperature between the COB LED light source and the heatsink is $50.9^{\circ}C$, which is $5.4^{\circ}C$ lower than the heatsink without the copper spread. Due to the improvement of the junction temperature, the light output is improved by 5.8% when the LED light source is stabilized. The temperature difference between the simulation and measured result of the heatsink with the copper spread is within $2^{\circ}C$, which verifies the validity of the thermal design method using a simulation package.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.161-167
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• 2015

The performance of high power LEDs highly depends on the junction temperature. Operating at high junction temperature causes elevation of the overall thermal resistance which causes degradation of light intensity and lifetime. Thus, appropriate thermal management is critical for LED packaging. The main goal of this research is to improve thermal resistance by optimizing and comparing nano-pore silicon-based thermal substrate to insulated metal substrate and direct bonded copper thermal substrate. The thermal resistance of the packages are evaluated using computation fluid dynamic approach for 1 W single chip LED module.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2038-2042
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• 2010

In this paper, we confirmed the thermal & optical properties for improving the heat transfer coefficient by changing the via hole size and in FR4 PCB with the same area. Osram 1W power LED Package (Golden Dragon) was used and the K-factor which is relative constant between LED junction temperature and forward bias was measured with power source meter(KEITHLEY 2430) to measure the thermal resistance from PCB configuration. As results, thermal resistance in metal PCB came out to the lowest as $26 [^{\circ}C/W]$ and thermal resistance in FR4 PCB without via-holes emerged as the highest as $69 [^{\circ}C/W]$. However thermal resistance of FR4 PCB could have decreased until $32[^{\circ}C/W]$ in 0.6 mm by using the via hole. Also, the luminous flux could have improved, too.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1347-1348
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• 2008

The efficacy and its degradation of light emitting diode(LED) are related to its PN junction's temperature(Tj). Currently efficacy in certain temperature and thermo-resistant are defined for the depending. However, the definitions are quite inconvenient for lighting application. The paper focuses on the issue and presents a method to evaluate the thermal characteristics of LED efficay.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2003.1-2004
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• 2011

LED는 친환경 광원으로써 메탈램프에 비해 높은 광 변환 효율과 긴 수명을 갖고 있어 차세대 광원으로 널리 쓰이고 있다. 그러나 이러한 특성은 LED의 접합온도가 일정하게 유지 되어야 가능하다. 실제 LED는 PN접합으로 구성되어 접합온도가 상승될 경우 광 변환 효율의 저하, 색온도의 변화, 사용 수명의 감축을 야기 시키는 요소로 작용한다. 따라서 LED는 방열설계가 중요하며 방열설계가 제대로 되지 못한 경우에 대해서는 온도보상이 필요하다. 본 논문은 LED모듈에 접합온도를 LED업체에서 제공하는 그래프를 이용하여 간접적으로 추정하고 LED의 접합온도를 일정하게 유지 시키는 시스템을 제안하였다.