Measurement of the junction temperature in high-power light-emitting diodes from the high-energy wing of the electroluminescence band

2008 ◽  
Vol 103 (9) ◽  
pp. 093110 ◽  
Author(s):  
Z. Vaitonis ◽  
P. Vitta ◽  
A. Žukauskas
Keyword(s):  
High Power ◽  
Light Emitting Diodes ◽  
High Energy ◽  
Junction Temperature ◽  
Light Emitting ◽  
Electroluminescence Band

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 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.

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

Junction Temperature Measurements in Deep-UV Light-Emitting Diodes

2004 ◽  
Vol 831 ◽  
Author(s):  
Y. Xi ◽  
J.-Q. Xi ◽  
Th. Gessmann ◽  
J. M. Shah ◽  
J. K. Kim ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Energy Gap ◽  
Uv Light ◽  
Accurate Method ◽  
High Energy ◽  
Junction Temperature ◽  
Forward Voltage ◽  
Light Emitting ◽  
Thermal Paste ◽  
Carrier Temperature

ABSTRACTThe junction temperature of AlGaN/GaN ultraviolet (UV) Light-Emitting Diodes (LEDs) emitting at 295 nm is measured by using the temperature coefficients of the diode forward voltage and emission peak energy. The high-energy slope of the spectrum is explored to measure the carrier temperature. A linear relation between junction temperature and current is found. Analysis of the experimental methods reveals that the diode-forward voltage is the most accurate method (± 3 °C). A theoretical model for the dependence of the diode junction voltage (Vj) on junction temperature (T) is developed that takes into account the temperature dependence of the energy gap. A thermal resistance of 87.6 K/W is obtained with the AlGaN/GaN LED sample mounted with thermal paste on a heat sink.

Dynamic junction temperature measurement for high power light emitting diodes

2011 ◽  
Vol 82 (8) ◽  
pp. 084904 ◽  
Author(s):  
Quan Chen ◽  
Xiaobing Luo ◽  
Shengjun Zhou ◽  
Sheng Liu
Keyword(s):  
Temperature Measurement ◽  
High Power ◽  
Light Emitting Diodes ◽  
Junction Temperature ◽  
Light Emitting
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