Research on LED temperature characteristic and thermal analysis at low temperatures

LED with the advantages of high brightness, long-lifetime, energy-saving and environmental protection is widely used in varieties of fields especially the lighting industry. Thermal performance is the key to high power LED lighting integration, which has got broad concern and research. And the thermal management and thermal reliability has been improved quickly in recent years. While, more and more lighting tools will be used outdoors at the temperature of twenty degrees below zero in winter and even lower in very frigid region, the corresponding technical requirements of the LED are not yet fully understood. Aiming at the special issue above, constant and variable temperature loading test with wide range of temperature are designed and implemented in this paper. In the accelerated test, the temperature cycles from 120 above zero to 50 minus degrees, and the performance parameters such as forward voltage and relative light intensity were analyzed, the relationship between the temperature and forward voltage, relative light intensity were developed at the same time. And then, ANSYS software was applied to simulate the extreme cold temperature accelerated aging test. Meanwhile, the stress and strain in extremely cold temperatures were predicted. Ultimately, based on statistical analysis of experimental data, an LED failure mode and the corresponding failure mechanism would be proposed in the condition of extremes low temperature. The technical requirements to prevent failure LED lamps at low temperatures were also reviewed.