the led industry is ever-expanding as more and more applications see the benefits of switching from halogen to led, including longer life, more flexibility in design and the lower operating temperature. while led are more efficient in turning electrical energy to light, there is still a certain amount of heat emitted and it could have an adverse effect on the product if the die temperature is not managed properly.
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a white paper published by electrolube discussed the thermal management options for led systems. it stated that heat sinks are the common tool for dissipating heat from the back of led components through conduction. in order to ensure the heat sinks work properly, it is important for a thermal interface material (tim) to be used to seal the air gaps at the junction between the heat sink and the component reducing the thermal resistance between the two.
electrolube offers several considerations when deciding on a tim, including whether or not to use a bonding agent, use silicone- or non-silicone-based materials, or to use a thermally conductive encapsulation resin that does not require a heat sink at all.
“the different chemistry options will provide a range of properties and each should be considered depending on the end application requirements,” read the report from electrolube.
the paper discusses the importance of thermal conductivity values when deciding on the proper thermal management technique. it stated, “relying on bulk thermal conductivity values alone will not necessarily result in the most efficient heat transfer.” rather than simply looking at thermal conductivity values, engineers should also take into consideration the thermal resistance, viscosity of the material and its ability to seal the air gaps to lower contact resistance, and the application thickness.
“electrolube has developed specific technologies to improve the ability to process thermal management compounds, easily and effectively,” the report continued. “this has resulted in reduced viscosity compounds with higher bulk thermal conductivities and with these two properties combined these products provide maximum efficiency in heat dissipation by minimizing thermal resistance.”
read the full paper at http://www.electrolube.com/technical-articles/thermal-management-of-leds-looking-beyond-thermal-conductivity-values/?sf=rnvapba.
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