Thermal resistance of high power LED on surface modified heat sink

2013 ◽  
Vol 6 (2) ◽  
pp. 160-166 ◽  
Author(s):  
D. Mutharasu ◽  
S. Shanmugan
Keyword(s):  
Thermal Resistance ◽  
High Power ◽  
Heat Sink ◽  
High Power Led ◽  
Surface Modified

Heat Sink Cooling Fan and Rotation Speed Effect Analysis on Heat Dissipation of High Power GaN LED Package

2014 ◽  
Vol 1082 ◽  
pp. 315-318
Author(s):  
Rajendaran Vairavan ◽  
Vithyacharan Retnasamy ◽  
Zaliman Sauli ◽  
Hussin Kamarudin ◽  
Muammar Mohamad Isa ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Rotation Speed ◽  
Junction Temperature ◽  
Von Mises Stress ◽  
Cooling Fan ◽  
High Power Led ◽  
Von Mises

In this work, thermal simulation analysis on high power LED is reported where the effect of the heat sink cooling fan and its rotation speed on the heat dissipation of the high power LED was evaluated. Ansys version 11 was utilized for the simulation. The thermal performance of the high power LED package was assessed in terms of operating junction temperature, von Mises stress and thermal resistance. The heat dissipation analysis was done under four types of convection condition:one natural convection conditionthree forced convection condition,. The forced convection condition was used to replicate the effect of a fan with various rotation speeds placed under the heat sink to increase the convective heat transfer coefficient. Results of the analysis showed that that the junction temperature, von Mises stress and thermal resistance of the GaN chip reduces with the increase of the fan rotation speed.

Improved Heat Dissipation and Optical Performance of High-power LED Packaging with Sintered Nanosilver Die-attach Material

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001585-001605 ◽  
Author(s):  
Paul Panaccione ◽  
Tao Wang ◽  
Guo-Quan Lu ◽  
Xu Chen ◽  
Susan Luo
Keyword(s):  
Thermal Resistance ◽  
High Power ◽  
Heat Removal ◽  
High Current ◽  
Die Attach ◽  
High Power Led ◽  
Silver Epoxy ◽  
The Difference ◽  
Nanosilver Paste ◽  
The Impact

Heat removal in packaged high-power light-emitting diode (LED) chips is critical to device performance and reliability. Thermal performance of LEDs is important in that lowered junction temperatures extend the LED's lifetime at a given photometric flux (brightness). Optionally, lower thermal resistance can enable increased brightness operation without exceeding the maximum allowable Tj for a given lifetime. A significant portion of the junction-to-case thermal resistance comes from the joint between chip and substrate, or the die-attach layer. In this study, we evaluated three different types of leading die-attach materials; silver epoxy, lead-free solder, and an emerging nanosilver paste. Each of the three was processed via their respective physical and chemical mechanisms: epoxy curing by cross-linking of polymer molecules; intermetalic soldering by reflow and solidification; and nanosilver sintering by solid-state atomic diffusion. High-power LED chips with a chip area of 3.9 mm2 were attached by the three types of materials onto metalized aluminum nitride substrates, wire-bonded, and then tested in an electro-optical setup. The junction-to-heatsink thermal resistance of each LED assembly was determined by the wavelength shift methodology, described in detail in this paper. We found that the average thermal resistance in the chips attached by the nanosilver paste was the lowest, and it is the highest from the chips attached by the silver epoxy: the difference between the two was about 0.7°C/W, while the difference between the sintered and soldered was about 0.3°C/W. The lower thermal resistance in the sintered joints is expected to significantly improve the photometric flux from the device. Simple calculations, excluding high current efficiency droop, predict that the brightness improvement could be as high as 50% for the 3.9 mm2 chip. The samples will be functionally tested at high current, in both steady-state and pulsed operation, to determine brightness improvements, including the impact of droop. Nanosilver die-attach on a range of chip sizes up to 12 mm2 are also considered and discussed.

Heat Dissipation Analysis of High Power LED Connected to Copper Coated Heat Sink by Soldering

2011 ◽  
Vol 32 (11) ◽  
pp. 1171-1175 ◽  
Author(s):  
柴伟伟 CHAI Wei-wei ◽  
陈清华 CHEN Qing-hua ◽  
李琳红 LI Ling-hong ◽  
唐文勇 TANG Wen-yong ◽  
张学清 ZHANG Xue-qing ◽  
...  
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
High Power Led

Structure Optimization of Radiation-Shaped Heat Sink for High Power LED

2012 ◽  
Vol 49 (10) ◽  
pp. 102201 ◽  
Author(s):  
李中 Li Zhong ◽  
李勇 Li Yong ◽  
汤应戈 Tang Yingge ◽  
林樵健 Lin Qiaojian
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Structure Optimization ◽  
High Power Led

scholarly journals Analysis and Prediction of Thermal Resistance for High Power LED Using GA-SVR

2012 ◽  
Vol 4 ◽  
pp. 153-160
Author(s):  
De Huai Zeng ◽  
Yuan Liu ◽  
Li Li ◽  
De Gui Yu ◽  
Gang Xu
Keyword(s):  
Service Life ◽  
Thermal Resistance ◽  
High Power ◽  
Thermal Characteristics ◽  
Junction Temperature ◽  
Support Vector ◽  
Mean Squared Errors ◽  
Absolute Relative Error ◽  
High Power Led ◽  
Key Factor

With the development of high power LED technology, junction temperature as a key factor constrains the performance and the service life of LED, and the main parameter of junction temperature is thermal resistance. Therefore, how to measure the thermal resistance of high power LED quickly and accurately plays an important part in improving the performance and the service life of LED. In this paper the accurate and fast measurement equipment was applied to study the thermal characteristics of high power LED. The forward-voltage based method was conducted to measure the junction temperature of high power. Then, support vector regression (SVR) combined with genetic algorithm (GA) for its parameter optimization, was proposed to establish a model to predict the thermal resistance of high power LED. The prediction performance of GA-SVR was compared with those of BPNN model. The result demonstrated that the estimated errors GA-SVR models, such as Mean Absolute Relative Error (MARE) and Root Mean Squared Errors (RMSE), all are smaller than those achieved by the BPNN applying identical samples.

Fabrication and testing of phase change heat sink for high power LED

2011 ◽  
Vol 21 (9) ◽  
pp. 2066-2071 ◽  
Author(s):  
Jian-hua XIANG ◽  
Chun-liang ZHANG ◽  
Fan JIANG ◽  
Xiao-chu LIU ◽  
Yong TANG
Keyword(s):  
Phase Change ◽  
High Power ◽  
Heat Sink ◽  
High Power Led

Improved Heat Dissipation and Optical Performance of High-Power LED Packaging with Sintered Nanosilver Die-Attach Material

2010 ◽  
Vol 7 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Paul Panaccione ◽  
Tao Wang ◽  
Xu Chen ◽  
Susan Luo ◽  
Guo-Quan Lu
Keyword(s):  
Thermal Resistance ◽  
High Power ◽  
Heat Removal ◽  
High Current ◽  
Die Attach ◽  
High Power Led ◽  
Silver Epoxy ◽  
The Difference ◽  
Nanosilver Paste ◽  
The Impact

Heat removal in packaged high-power light-emitting diode (LED) chips is critical to device performance and reliability. Thermal performance of LEDs is important in that lowered junction temperatures extend the LED's lifetime at a given pho-tometric flux (brightness). Optionally, lower thermal resistance can enable increased brightness operation without exceeding the maximum allowable Tj for a given lifetime. A significant portion of the junction-to-case thermal resistance comes from the joint between chip and substrate, or the die-attach layer. In this study, we evaluated three different types of leading die-attach materials; silver epoxy, lead-free solder, and an emerging nanosilver paste. Each of the three was processed via their respective physical and chemical mechanisms: epoxy curing by cross-linking of polymer molecules; intermetalic soldering by reflow and solidification; and nanosilver sintering by solid-state atomic diffusion. High-power LED chips with a range of chip areas from 3.9 mm2 to 9.0 mm2 were attached by the three types of materials onto metalized aluminum nitride substrates, wire-bonded, and then tested in an electro-optical setup. The junction-to-heatsink thermal resistance of each LED assembly was determined by the wavelength shift methodology. We found that the average thermal resistance in the chips attached by the nanosilver paste was the lowest, and it was highest from the chips attached by the silver epoxy. For the 3.9 mm2 die, the difference was about 0.6°C/W, while the difference between the sintered and soldered was about 0.3°C/W. The lower thermal resistance in the sintered joints is expected to significantly improve the photometric flux from the device. Simple calculations, excluding high current efficiency droop, predict that the brightness improvement could be as high as 50% for the 3.9 mm2 chip. The samples will be functionally tested at high current, in both steady-state and pulsed operation, to determine brightness improvements, including the impact of droop. Nanosilver die-attach on a range of chip sizes up to 12 mm2 are also considered and discussed.

Thermal Simulation Analysis of High Power LED with Varied Heat Sink Fin Design

2014 ◽  
Vol 1082 ◽  
pp. 332-335
Author(s):  
Vithyacharan Retnasamy ◽  
Zaliman Sauli ◽  
Hussin Kamarudin ◽  
Muammar Mohamad Isa ◽  
Gan Meng Kuan
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Simulation Analysis ◽  
Input Power ◽  
Junction Temperature ◽  
Single Chip ◽  
Pin Fin ◽  
High Power Led ◽  
Different Shapes ◽  
Fin Design

In this paper, the heat distribution for single chip high power LED package attached with varied heat sink fin shapes were analyzed through simulation. The main focus of this study was to scrutinize the fluctuation of junction temperature with different shapes of heat sink fin designs. The simulation was done using Ansys version 11. The single chip LED was loaded with input power of 0.5 W and 1 W . Simulation was done at ambient temperature of 25°C under three convection coefficient of 5, 10 and 15 W/m2.oC respectively. The obtained results showed that the LED package with pyramid pin fin heat sink has demonstrated a better thermal performance compared to the LED package with cylindrical pin fin heat sink.

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