At present, the biggest technical problem of LED lighti […]
At present, the biggest technical problem of LED lighting is heat dissipation. The poor heat dissipation leads to the shortage of LED driving power supply and electrolytic capacitor, which is the cause of premature aging of LED lighting.
In the lamp scheme using LV LED light source, because the LED light source works at low voltage (VF=3.2V) and high current (IF=300-700 mA), the heat is very strong, the space of traditional lamp is narrow, and it is difficult for small area radiator to quickly derive heat. Despite the use of a variety of heat dissipation schemes, the results are unsatisfactory, which has become an unsolvable problem for LED lighting. Looking for easy-to-use, good thermal conductivity, and low-cost heat dissipation materials has always been in the effort.
At present, about 30% of the electric energy of LED light source is converted to light energy, while the rest is converted to heat energy. Therefore, to export so much heat energy as soon as possible is the key technology of the structure design of LED lamps, heat energy needs to be transmitted through heat conduction, heat convection and heat radiation. Only by exporting heat as soon as possible can the cavity temperature in the LED lamps be effectively reduced, the power supply can not work under the permanent high temperature environment, and the premature aging of the LED light source due to the long-term high temperature operation can be avoided.
Heat Dissipation Way of LED Lighting Lamps
Because the LED light source itself does not have infrared and ultraviolet radiation, so the LED light source itself does not have radiation heat dissipation function. The heat dissipation way of the LED lighting lamps can only be derived through the radiator which is closely combined with the LED lamp bead board. The radiator must have the functions of heat conduction, convection and radiation.
Any radiator, in addition to the rapid transfer of heat from the source of heat to the surface of the radiator, relies mainly on convection and radiation to transmit heat to the air. Heat conduction only solves the way of heat transfer, and heat convection is the main function of the radiator. The heat dissipation performance is mainly determined by the heat dissipation area, shape and the ability of natural convection intensity. Thermal radiation is only an auxiliary role.
Generally speaking, if the distance of heat from the heat source to the radiator surface is less than 5 mm, the heat can be derived as long as the thermal conductivity of the material is greater than 5, and the rest of the heat dissipation must be dominated by heat convection.
Most LED lighting sources still use LED beads with low voltage (VF=3.2V) and high current (IF=200-700 mA). Aluminum alloy with high thermal conductivity must be used because of its high heat during operation. Usually there are die-casting aluminum radiator, extrusion aluminum radiator, stamping aluminum radiator. Die-casting aluminium radiator is a technology of die casting parts. The liquid zinc, copper and aluminium alloy is poured into the inlet and outlet of the die casting machine, and the shape radiator defined by the die casting machine is cast.