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Rao F.,Changzhou Institute of Technology | Rao F.,Key Laboratory of Optoelectronic Materials and Devices of Changzhou | Guo J.,Changzhou Institute of Technology | Zhu X.-F.,Changzhou Institute of Technology | Xu A.-C.,Changzhou Institute of Technology
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2014

The normalized spectral power distributions of the LED arrays with various substrate temperatures and 350 mA drive current were measured, the centriod wavelengths were calculated, and then the relationships between the centriod wavelength and the change in the average junction temperatures of LED arrays were analyzed. Finally, the accuracy of the new method was studied. The results show that the centriod wavelength measured with spectrometer of 1 nm step changes linearly with the variation of average junction temperature, and the linearity is much better than that of the proposed center wavelength method. Moreover, the precision of estimating the junction temperature with the centroid wavelength is much higher. Therefore, the centroid wavelength test would be an effective method to determine the average junction temperature of AlGaInP-based LED array. Source


Rao F.,Changzhou Institute of Technology | Rao F.,Key Laboratory of Optoelectronic Materials and Devices of Changzhou | Zhu X.,Changzhou Institute of Technology | Xu A.,Changzhou Institute of Technology
Guangxue Xuebao/Acta Optica Sinica | Year: 2014

A new method for determining the average junction temperature of AlGaInP-based light emitting diode (LED) array is developed based on the difference of normalized spectral distribution. The normalized spectra of three LED arrays with various injected powers and substrate temperatures are measured with a spectrometer, and the relationship between the differences of normalized spectral distributions and the average junction temperatures of LED arrays is analyzed. The accuracy of evaluating junction temperature with the difference of normalized spectral distributions is compared with the proposed method using center wavelength shift. The results show that the difference of normalized spectral distributions, measured with a spectrometer of 1 nm sample interval, changes linearly with the variation of average junction temperature whether it is induced by the change of the injected power or the substrate temperature, and the linearity is better than that of the method using center wavelength shift. Therefore, the difference of normalized spectral distributions can be used to estimate the average junction temperature, and the accuracy is better than the method using center wavelength shift. Source

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