Like traditional light sources, semiconductor light-emitting diodes (LEDs) also generate heat during operation, the amount of which depends on the overall luminous efficiency.

Under the action of external electric energy, the radiation of electrons and holes recombine to produce electroluminescence. The light radiated near the PN junction also needs to pass through the semiconductor medium and packaging medium of the chip itself to reach the outside (air). Combining current injection efficiency, radioluminescence quantum efficiency, and chip external light extraction efficiency, in the end, only about 30-40% of the input electric energy is converted into light energy, and the remaining 60-70% of the energy is mainly caused by non-radiative recombination of lattice vibration Form transforms heat energy.

LED heat dissipation method

Aluminum fins

This is the most common way to dissipate heat. Aluminum fins are used as part of the housing to increase the heat dissipation area.

Thermally conductive plastic shell

The use of LED insulation and heat dissipation plastic instead of aluminum alloy to make the heat sink can greatly improve the heat radiation capacity.

Surface radiation heat treatment

The surface of the lamp housing is treated with radiant heat. The simple method is to apply radiant heat dissipation paint, which can take the heat away from the surface of the lamp housing by radiation.

Aerodynamics

The shape of the lamp housing is used to create convective air, which is the lowest cost way to enhance heat dissipation.

fan

Long-life and high-efficiency fans are used inside the lamp housing to enhance heat dissipation, which has low cost and good effect. However, it is more troublesome to change the fan, and it is not suitable for outdoor use. This kind of design is relatively rare.

Heat pipe

Using heat pipe technology, heat is conducted from the LED chip to the heat dissipation fins of the housing. It is a common design in large lamps, such as street lamps.

Liquid bulb

Using liquid bulb packaging technology, a transparent liquid with high thermal conductivity is filled into the bulb of the lamp body. This is the only technology that uses the light emitting surface of the LED chip to conduct heat and dissipate heat in addition to the principle of light reflection.

Use of lamp holder

In household-type low-power LED lamps, the internal space of the lamp holder is often used to partially or completely insert the heating drive circuit. In this way, a lamp cap with a larger metal surface such as a screw cap can be used to dissipate heat, because the lamp cap is closely connected to the metal electrode of the lamp holder and the power cord. Therefore, a part of the heat can be radiated from this.

Integration of heat and heat dissipation--application of high thermal conductivity ceramics

The purpose of the heat dissipation of the lamp housing is to reduce the working temperature of the LED chip. Since the expansion coefficient of the LED chip is very different from the expansion coefficient of our commonly used metal heat conduction and heat dissipation materials, the LED chip cannot be directly welded to avoid high and low temperature thermal stress to damage the LED chip. The latest high thermal conductivity ceramic material, the thermal conductivity is close to aluminum, and the expansion system can be adjusted to synchronize with the LED chip. In this way, heat conduction and heat dissipation can be integrated, reducing the intermediate links of heat conduction.

PVC modified material

With thermal conductivity function, secondary packaging.