The study on thermal crowding in high-power white light-emitting diode devices on luminaires

High power white-LEDs are considered as the next generation light source. However, reliability concerns related with thermal loads of white-LED products become very serious, hindering the wide application of LED products. Previous researchers mainly focused on the functions of the under-cooling channels on heat management, ignoring the possibility of heat accumulation in the upper space of LED chips. In this work, we set up a measurement system to examine the temperature distribution in luminaires. Since it is difficult to locate accurately the thermal crowding regions inside the LED devices based on testing equipment, finite element simulations are used to help understanding the thermal crowding phenomenon in LEDs. Key parameters for numerical simulation usage are obtained experimentally. The results can provide an important reference on designing the packaging structure of LED devices, thus improving the heat dissipation and reliability of LEDs.