| Summary: | 碩士 === 國立交通大學 === 電子物理系所 === 92 === In this study, we have set up a system to measure LED junction temperature. In this thesis, we first introduce the operation principle of the experiment, the establishment of the system, and the selection of the measurement conditions. In the selection of the measurement conditions, four important parameters are included：measurement current (IM), temperature coefficient of junction voltage (Kj), cooling time(tC), heating time (tH). Then, we follow the selection rule of the system to choose these four parameters and prove them from the result of the experiments. We find the blue light-emitting diodes, behave pretty much as we have predicted. But the red light-emitting diodes, maybe due to its structure, behave differently from the blue light-emitting diodes. In the junction temperature measurements, we get reasonable curves and also confirm the accuracy of the system’s measurements further. In addition, in comparing of the junction temperature and the light-emitting diode spectrum, we see the junction temperature has certain effect to the decay of the light output power of light-emitting diodes.
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