Junction Temperature and Thermal Resistance Measurement in High-Power Light Emitting Diodes Using A Real-Time Diode Forward Voltage Sampling Technique

2006 ◽  
Author(s):  
Shui-Jinn Wang ◽  
Tron-Min Chen ◽  
Kai-Ming Uang ◽  
Shiue-Lung Chen ◽  
Der-Ming Kuo ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Real Time ◽  
High Power ◽  
Light Emitting Diodes ◽  
Sampling Technique ◽  
Resistance Measurement ◽  
Junction Temperature ◽  
Forward Voltage ◽  
Light Emitting

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.

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