Heat Dissipation Material Of High-power LED
- Sep 07, 2017-
High power light-emitting diodes (LEDs) can use 350 milliwatts or more in a single LED. Most of the electricity in an LED becomes heat rather than light (about 70% heat and 30% light). If this heat is not removed, the LEDs run at high temperatures, which not only lowers their efficiency, but also makes the LED less reliable. It is necessary to limit the junction temperature to a value that will guarantee the desired LED lifetime.
In order to attain a low junction temperature to keep good performance of LED, every method of removing heat from LEDs should be considered,e.g conduction,convection and radiation are the three typical methods of heat transfer. Such heat dissipation is achieved by using heat sink and heat spreader packaging materials to prevent the failure of semiconductor devices.Because heat sink provides a path for heat from the LED source to outside medium. Heat sinks can dissipate power in three ways: conduction (heat transfer from one solid to another), convection (heat transfer from a solid to a moving fluid, for most LED applications the fluid will be air), or radiation(heat transfer from two bodies of different surface temperatures through thermal radiation).
The thermal conductivity of the material that the heat sink is made from directly affects the dissipation efficiency through conduction.By using the rapid solidification technology, the patented technology is suitable to produce the high silicon content Si-Al alloy(70%Si-Al). The microstructure is observed by scanning electrical microscopy(SEM) is homogeneous and isostatic. Besides,the average grain size is within 20 microns and the compactness of aluminum is up to 99.2%. This material occupies advantages of the coefficient of thermal expansion(CTE) match to Si or GaAs with a value of 7×10-6/℃,and posses the higher thermal conductivity of 120 W/(mK) and low density of 2.43 g/cm-3.Furthermore,the high silicon aluminum(Si-Al) alloy has a specific stiffness and plateable.So it becomes the ideal material for electronic packaging arena and many semiconductor devices.