What are the reasons for the heating of the LED display? Since heat and heat are directly related to the service life of the LED display lamp beads, this problem has always been the key research object of major manufacturers and researchers. Let's take a look at the causes of heat generation in the LED display.
Quali sono i motivi per cui il display a LED si surriscalda? Cosa fare
Causes of LED heating:
The reason why the LED heats up is because the added electric energy is not all converted into light energy, but part of it is converted into heat energy. The luminous efficiency of LED is only 100lm/W, and its electro-optical conversion efficiency is only about 20-30 percent . In other words, about 70 percent of the electrical energy is turned into heat.
Specifically, the LED junction temperature is caused by two factors:
1. The internal quantum efficiency is not high, that is, when electrons and holes are recombined, 100 percent of photons cannot be generated. It is usually referred to as "current leakage" which reduces the recombination rate of carriers in the PN region. The leakage current multiplied by the voltage is the power of this part, which is converted into heat energy, but this part does not account for the main component, because the internal photon efficiency is close to 90 percent .
2. The photons generated inside cannot all be emitted to the outside of the chip and converted into heat. This part is the main one, because the so-called external quantum efficiency is only about 30 percent , and most of them are converted into heat.
LED cooling solution:
To solve the heat dissipation of the LED, we mainly start from two aspects. Before and after packaging, it can be understood as the heat dissipation of the LED chip and the heat dissipation of the LED lamp. The heat dissipation of the LED chip is mainly related to the choice of substrate and circuit and the process. Because any LED will be made into a lamp, the heat generated by the LED chip is always dissipated into the air through the shell of the lamp. If the heat dissipation is not good, because the heat capacity of the LED chip is very small, a little heat accumulation will make the junction temperature of the chip increase rapidly. If it is operated at a high temperature for a long time, its life will be shortened quickly. However, there are many ways for this heat to actually guide the chip to the outside air. Specifically, the heat generated by the LED chip comes out of its metal heat sink, first passes through the solder to the aluminum substrate PCB, and then passes through the thermal conductive glue to the aluminum heat sink. Therefore, the heat dissipation of LED lamps actually includes two parts: heat conduction and heat dissipation.
However, the heat dissipation of the LED lamp housing will have different options depending on the power size and the place of use. There are mainly the following heat dissipation methods:
Aluminum fins: This is a common way to dissipate heat. Use aluminum fins as part of the housing to increase the heat dissipation area.
Thermally conductive plastic shell: Fill the plastic shell with thermally conductive material during injection molding to increase the thermal conductivity and heat dissipation capacity of the plastic shell.
Aerodynamics The use of the shape of the lamp housing to create convective air is a low-cost way to enhance heat dissipation.
The inside of the fan lamp housing uses a long-life and high-efficiency fan 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 The heat pipe technology is used to conduct heat from the LED chip to the heat dissipation fins of the housing. It is a common design in large lamps, such as street lamps.
Surface radiation heat treatment The surface of the lamp housing is treated with radiation heat. Simply apply Zhisheng Weihua radiation heat dissipation paint to take the heat away from the surface of the lamp housing in a radiant manner.
Generally speaking, the luminous efficiency of the LED is still relatively low, which causes the junction temperature to rise and the lifetime to decrease. In order to reduce the junction temperature and increase the life, it is necessary to attach great importance to the issue of heat dissipation.
LED display has overheating problem
LED display sometimes has the problem of excessive heating, which is accompanied by complications such as display blurring, garbled characters, and incomplete display. This situation is generally caused by a problem with the control card or a partial short circuit on the ic surface. This kind of problem can be solved by replacing the control card or the ic module with the problem.
