Why do LEDs need radiators?

Last Update Time: 2019-06-14 15:59:13

At present, one of the biggest technical problems of LED lighting fixtures is the heat dissipation problem. The LED heat supply and electrolytic capacitors have become the short-term development of LED lighting fixtures, and the cause of premature aging of LED light sources.


Only by exposing the heat as soon as possible can the cavity temperature in the LED lamp be effectively reduced, in order to protect the power supply from working in a long-lasting high temperature environment, in order to avoid premature aging of the LED light source due to long-term high temperature operation.


Because the LED light source itself does not have infrared rays or ultraviolet rays, the LED light source itself has no radiation heat dissipation function, and the heat dissipation path of the LED lighting fixture can only derive heat through a heat sink closely combined with the LED lamp bead. The heat sink must have the functions of heat conduction, heat convection, and heat radiation.


Any radiator, in addition to being able to quickly transfer heat from the heat source to the surface of the radiator, the most important thing is to convect and radiate heat into the air. Thermal conduction only solves the heat transfer path, and thermal convection is the main function of the heat sink. The heat dissipation performance is mainly determined by the heat dissipation area, shape, and natural convection strength. Thermal radiation is only an auxiliary function. In general, if the distance of heat from the heat source to the surface of the heat sink is less than 5 mm, then as long as the thermal conductivity of the material is greater than 5, the heat can be derived, and the rest of the heat must be dominated by heat convection.


Most LED lighting sources still use low voltage (VF=3.2V), high current (IF=200-700mA) LED lamp beads. Due to the high heat during operation, aluminum alloy with high thermal conductivity must be used. There are usually die-cast aluminum radiators, extruded aluminum radiators, and stamped aluminum radiators. Die-cast aluminum radiator is a kind of technology for pressure casting parts. The liquid zinc-copper-aluminum alloy is poured into the inlet of the die-casting machine, and die-casting is carried out by a die-casting machine to cast a shape heat sink defined by a pre-designed mold.