Ideas and solutions for the high temperature of LED street lights
The high temperature of LED street lamps will affect the service life of LED lamps. LED street lamp manufacturers ED street lamps have much higher light color rendering than high-pressure sodium lamps. The color rendering index of high-pressure sodium lamps is only about 23, while the color rendering index of LED street lamps is more than 75. From the perspective of visual psychology, it can reach the same brightness and the illuminance of LED street lamps is average. It can be reduced by more than 20% compared with high-pressure sodium lamps. Low maintenance cost of LED street lights: Compared with traditional street lights, the maintenance cost of LED street lights is extremely low. After comparison, all input costs can be recovered in less than 6 years. The LED street lamp has an automatic control energy-saving device, which can achieve the greatest possible reduction in power and energy saving under the condition of meeting the lighting requirements of different periods. It can realize computer dimming, time period control, light control, temperature control, automatic inspection and other humanized functions. It is believed that the lower the temperature, the life of the light-emitting diode is inversely proportional to the junction temperature. The higher the temperature of the balance, the lower the service life. The radiator is to solve the heat dissipation problem, as long as its temperature does not exceed the temperature that it can withstand. The key is the temperature of the chip. In order to achieve the effect of rapid diffusion and dispersion, the heat generated by the LED street lamp must be quickly transferred to the radiator.
LED street lamp high temperature concept: the relationship between street lamp size and heat dissipation. The most direct way to increase the brightness of power LEDs is to increase the input power to prevent the active saturation layer. The size of the pn junction must be increased accordingly; the input power will inevitably increase the junction temperature, thereby reducing Quantum efficiency. The increase of single tube power depends on the ability of the device to obtain heat from the pn junction, as well as maintaining the chip material, structure, packaging process, current density on the chip and equivalent heat dissipation. The use of LED street lamp heat sinks is the most common way to dissipate heat, using LED aluminum heat sinks as part of the housing to increase heat dissipation. Thermally conductive plastic housing. The use of LED insulating and heat-dissipating plastic instead of aluminum alloy to make the heat sink can greatly improve the heat dissipation capacity. Surface radiation heat treatment. The surface of the lampshade radiates and dissipates heat. The simple method is to apply radiant heat-dissipating paint, which can radiate heat from the surface of the lampshade. Aerodynamics uses the shape of the lamp housing to generate convective air, which is the lowest cost way to enhance heat dissipation. The purpose of heat dissipation of the lamp housing is to reduce the operating temperature of the LED chip. Since the expansion coefficient of the LED chip is very different from the expansion coefficient of commonly used metal thermal and heat dissipation materials, the LED chip cannot be directly welded to avoid high temperature and low temperature thermal stress from damaging 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 to reduce the middle part of heat conduction. The inside of the fan and the lamp housing adopts a long-life and high-efficiency fan to enhance the heat dissipation effect, with low cost and good effect. However, replacing the fan is more troublesome and is not suitable for outdoor use. This design is less common in liquid bulbs. Liquid bubble packaging technology is used to fill the bulb of the lamp body with a transparent liquid with high thermal conductivity. In addition to the reflection principle, this is the only technology that uses the light-emitting surface of the LED chip to conduct heat and dissipate heat. The use of the lamp holder In household low-power LED lamps, the internal space of the lamp holder is usually used to partially or completely place the heating drive circuit. This makes it possible to dissipate heat from a lamp cap with a large metal surface, such as a screw cap, because the lamp cap is in close contact with the metal electrode of the lamp holder and the power cord. Therefore, part of the heat can come from heat dissipation. High thermal conductivity ceramics that integrate heat and heat dissipation are used.
Six solutions to the high temperature of LED street lights:
1. Super thermal conductivity: The microgroove group composite phase change cooling technology has super thermal conductivity, and its thermal conductivity is 10,000 times that of the aluminum matrix. This technology can transfer the heat of the LED chip to an infinite heat dissipation surface in time. The thermal conductivity is greater than 106W/(m*℃).
