Solid-state light emitting devices, such as light-emitting diodes (LEDs), have become more common in curing applications such as those using ultra-violet light. Solid-state light emitters have several advantages over traditional mercury arc lamps including that they use less power, are generally safer, and are cooler when they operate.
However, even though they generally operate at cooler temperatures than arc lamps, they do generate heat. Since the light emitters generally use semiconductor technologies, extra heat causes leakage current and other issues that result in degraded output. Management of heat in these devices allows for better performance. As the demand rises for higher irradiance output from these devices heat management becomes more important.
One traditional cooling technique uses a heat sink, which generally consists of thermally conductive materials mounted to the substrates upon which the light emitters reside. Some sort of cooling or thermal transfer system generally interacts with the back side of the heat sink, such as heat dissipating fins, fans, liquid cooling, etc., to draw the heat away from the light emitter substrates. The efficiency of these devices remains lower than desired, and liquid cooling systems can complicate packaging and size restraints. However, transferring the heat from the LED to the liquid allows the liquid to transport the heat away from the LED resulting in efficient cooling.
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