Effect of junction temperature on heat dissipation of high power light emitting diodes

2016 ◽  
Vol 119 (12) ◽  
pp. 125104 ◽  
Author(s):  
Dae-Suk Kim ◽  
Bongtae Han
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Junction Temperature ◽  
Light Emitting

scholarly journals High-Power GaN-Based Vertical Light-Emitting Diodes on 4-Inch Silicon Substrate

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1178 ◽  
Author(s):  
Qiang Zhao ◽  
Jiahao Miao ◽  
Shengjun Zhou ◽  
Chengqun Gui ◽  
Bin Tang ◽  
...  
Keyword(s):  
High Power ◽  
Silicon Substrate ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Current Spreading ◽  
Light Emitting ◽  
Fabry Perot ◽  
Lift Off

We demonstrate high-power GaN-based vertical light-emitting diodes (LEDs) (VLEDs) on a 4-inch silicon substrate and flip-chip LEDs on a sapphire substrate. The GaN-based VLEDs were transferred onto the silicon substrate by using the Au–In eutectic bonding technique in combination with the laser lift-off (LLO) process. The silicon substrate with high thermal conductivity can provide a satisfactory path for heat dissipation of VLEDs. The nitrogen polar n-GaN surface was textured by KOH solution, which not only improved light extract efficiency (LEE) but also broke down Fabry–Pérot interference in VLEDs. As a result, a near Lambertian emission pattern was obtained in a VLED. To improve current spreading, the ring-shaped n-electrode was uniformly distributed over the entire VLED. Our combined numerical and experimental results revealed that the VLED exhibited superior heat dissipation and current spreading performance over a flip-chip LED (FCLED). As a result, under 350 mA injection current, the forward voltage of the VLED was 0.36 V lower than that of the FCLED, while the light output power (LOP) of the VLED was 3.7% higher than that of the FCLED. The LOP of the FCLED saturated at 1280 mA, but the light output saturation did not appear in the VLED.

Study the Effect of Junction Temperature on the Peak Wavelength in GaN-Based High-Power Green Light Emitting Diodes

2011 ◽  
Vol 399-401 ◽  
pp. 1034-1038
Author(s):  
Rong Rong Zhuang ◽  
Ping Cai ◽  
Jiang Li Huang
Keyword(s):  
High Power ◽  
Temperature Rise ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Red Shift ◽  
Junction Temperature ◽  
Spectral Peak ◽  
Peak Wavelength ◽  
Drive Current ◽  
Light Emitting

The junction temperature of GaN-based high-power green light emitting diodes is measured using the temperature coefficients of the diode forward voltage, from changes in temperature and changes in drive current to measure the LED junction temperature and the corresponding spectral, Respectively. Experiments show that, junction temperature due to environmental temperature increased, and the red shift of the spectral peak wavelength. When low temperature or less then the rated current range, the drive current increased in junction temperature rise due to the spectral peak wavelength blue shift . When the current is increased in the range of close to or greater than the rated current, leading to the junction temperature rise will cause spectral red shift . The peak wavelengths’ shift degree of 0.0579nm / k, 0.0751 nm / k and-0.1974nm / k, -0.0915 nm / k are calculated in both cases. The phenomenon is due to the LED junction temperature increases lead to band gap shrinkage, and the result of the role of spontaneous polarization and piezoelectric polarization in Ⅲ-nitride semiconductor materials.

Thermal Analysis of High Power Light Emitting Diodes Package

2011 ◽  
Vol 687 ◽  
pp. 215-221
Author(s):  
Yuan Yuan Han ◽  
Hong Guo ◽  
Xi Min Zhang ◽  
Fa Zhang Yin ◽  
Ke Chu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
High Power ◽  
Thermal Field ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Convective Heat Exchange ◽  
Input Power ◽  
Junction Temperature ◽  
Original Structure ◽  
Light Emitting

With increasing of the input power of the chips in light emitting diode (LED)， the thermal accumulation of LEDs package increases. Therefore solving the heat issue has become a precondition of high power LED application. In this paper, finite element method was used to analyze the thermal field of high power LEDs. The effect of the heatsink structure on the junction temperature was also investigated. The results show that the temperature of the chip is 95.8°C which is the highest, and it meets the requirement. The conductivity of each component affects the thermal resistance. Convective heat exchange is connected with the heat dissipation area. In the original structure of LEDs package the heat convected through the substrate is the highest, accounting for 92.58%. Three heatsinks with fin structure are designed to decrease the junction temperature of the LEDs package.

Thermal Characteristics of High-Power LED Packages with Dissipation Film

2013 ◽  
Vol 397-400 ◽  
pp. 1767-1771
Author(s):  
Cheng Yi Hsu ◽  
Yu Li Lin
Keyword(s):  
High Power ◽  
Diamond Film ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Thermal Characteristics ◽  
Large Change ◽  
Junction Temperature ◽  
Conduction Model ◽  
Element Analysis ◽  
Light Emitting

A simple, fast, and reliable characterization method for measuring junction temperature (Tj) on high power GaN-based light emitting diodes (LED) was presented in this study. Thermal characteristics of high power Light-emitting-diode have been analyzed by using a three-dimensional thermal conduction model. Maximum operation temperature has also been calculated. The induced thermal behaviors of the best package processes for LED device with diamond film were investigated by finite element analysis (FEA) and by experimental measurement. The large change of forward operation voltage with temperature in light emitting diodes is advantageously used to measure junction temperature. Using this method, junction temperature (Tj) of LED under various structures and chip mounting methods was measured. It was found that the junction temperature can be reduced considerably by using diamond film substrates to replace sapphire substrate. In this study, the junction temperature can be decreased by about 14.3% under 1.5W power and decreased by about 15.9% under 1W power for 1mm square die. The thermal resistance (RT) can be measured to be 14.8°C/W under 1.5W power and 16.6°C/W under 1.W power.

Numerical Analysis for Thermal Performance of High Power Multi-Chip LED Packaging

2010 ◽  
Vol 139-141 ◽  
pp. 1433-1437
Author(s):  
Kai Lin Pan ◽  
Jiao Pin Wang ◽  
Jing Liu ◽  
Guo Tao Ren
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Junction Temperature ◽  
Light Emitting ◽  
Die Attach ◽  
Dissipation Model ◽  
Key Issues

Heat dissipation and cost are the key issues for light-emitting diode (LED) packaging. In this paper, based on the thermal resistance network model of LED packaging, three-dimensional heat dissipation model of high power multi-chip LED packaging is developed and analyzed with the application of finite element method. Temperature distributions of the current multi-chip LED packaging model are investigated systematically under the different materials of the chip substrate, die attach, and/or different structures of the heat sink and fin. The results show that the junction temperature can be decreased effectively by increasing the height of the heat sink, the width of the fin, and the thermal conductivity of the chip substrate and die attach materials. The lower cost and higher reliability for LED source can be obtained through reasonable selection of materials and structure parameters of the LED lighting system.

Junction temperature and reliability of high-power flip-chip light emitting diodes

2007 ◽  
Vol 10 (4-5) ◽  
pp. 206-210 ◽  
Author(s):  
Z.Z. Chen ◽  
P. Liu ◽  
S.L. Qi ◽  
L. Lin ◽  
H.P. Pan ◽  
...  
Keyword(s):  
High Power ◽  
Flip Chip ◽  
Light Emitting Diodes ◽  
Junction Temperature ◽  
Light Emitting
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