several major errors of cooling LED and coping methods

led street light

LED heat misunderstanding is mainly reflected in the following aspects:
An internal quantum efficiency is not high. led street light fixture is when the electron and hole recombination, and can not produce 100% of all photons, commonly referred to as the “current leakage” of carriers leaving the PN zone composite rate. Leakage current times the voltage that this part of the power, which is converted into heat, but this part does not account for the main component, because the internal photon efficiency is close to 90%.
2 internally generated photons emitted to the outside of the chip can not be fully converted to the final heat. This part is mainly because this is called the external quantum efficiency is currently only about 30%, most of them converted to heat up.
3 undue reliance on thermal conductivity material. Because what the high-tech materials can be used to shed heat. In fact, with ordinary aluminum heat, after several tests, the heat sink temperature is 3-5 degrees Celsius higher than the bottom of the radiator only. That is, if a true thermal conductivity can be used to especially good material, the thermal resistance in the case of zero, it can lower the temperature 3-5 degrees Celsius.
4 superstition heat pipe. Heat pipe has a very good thermal capacity, which is beyond doubt. But ultimately derived thermal heat sink through the tropical air convection away. If there is no cooling fins, heat pipes will soon reach thermal equilibrium, the temperature rise together with the heat sink. And if the increase in the heat pipe heat sink, eventually radiating fins. And the contact point fin and tube heat exposure is good but not as good in other ways. The result is a high cost, the cooling effect is not improved. However, to use the integrated heat pipe thermal LED on or useful, but reasonable to structure!
5 credulous some manufacturers nm radiation publicity material. Radiation heat LED lamps in the present case temperature of 50 degrees Celsius proportion can be ignored. The radiation coating manufacturers propaganda propaganda even as they did have a good radiation effects, radiation even reached blackbody radiation, the thermal gravity but a few percent. And the coating itself will hinder the export of heat, thus affecting the thermal convection.
LED thermal problems coping methods:
1, aluminum fins
This is the most common way of cooling, aluminum fins as part of the housing to increase the cooling area.
2, thermal plastic case
LED thermal insulation using plastic replacement heat sink aluminum production, can significantly improve the thermal radiation.
3, the air hydrodynamic
Use light shell shape, creating a convection air, which is the lowest-cost way to enhance heat dissipation.
4, liquid bulb
The use of liquid bulb packaging technology, high thermal conductivity of the transparent liquid filled bulb in the lamp body. This is in addition to reflective principle, the only use of led street light fixture chip smooth thermal conductivity, thermal technology.
The use of 5-head
In the home-based lower power LED lamps, lamp often use an internal space, the driver circuit portion or all of the heat into. Such as screw cap can be used with such a large cooling metal surface of the lamp, because the lamp is a metal electrode and the socket-contact power supply line. So part of the heat can be derived therefrom heat.
6, thermal insulation aluminum plastic alternative
Thermal insulation of aluminum alloy heat sink plastic alternatives, this LED thermal plastic insulation, while maintaining cooling capacity with aluminum flat, raise the heat radiation 4-8 times. With this heat produced by the LED heat sink materials significantly enhance the overall physical cooling effect .
7, thermal heat integration – the use of high thermal conductivity ceramic
The purpose is to reduce the heat of the lamp envelope of the operating temperature of the LED chip, the led street light fixture we used the thermal expansion coefficient and thermal conductivity of metal, thermal expansion coefficient, a large gap between the material can not be welded directly to the LED chip, so high, low thermal stress damage of the LED chip. New ceramic material with high thermal conductivity, thermal conductivity close to aluminum, the expansion factor can be adjusted to synchronize with the LED chip. This can be thermal, heat integration, reduce heat conduction intermediate links.

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