The cause of LED lamp heating

- Jun 21, 2019-

LED bulbs are hot in the market, leading brands online shop prices dazzling, expensive also have expensive reason, cheap also have cheap market. Today small make up to say one of the disadvantages of LED bulbs: heat. What if the LED bulb heats up? LED will generate heat, many people will think that LED is a cold light source, this just refers to the luminous principle of LED

By integrating current injection efficiency, radiant luminescence quantum efficiency and chip external light removal efficiency, only 30-40% of the input electric energy is converted into light energy, and the rest 60-70% of the energy is mainly converted into heat energy in the form of non-radiation composite lattice vibration.

However, the increase of chip temperature will enhance the non-radiation recombination and further weaken the luminescence efficiency. Because, subjectively, people think that high-power leds have no heat, and they do. So much heat that problems occur during use. In addition, many people who use high-power LED for the first time do not know how to solve the thermal problem effectively, making the product reliability become the main problem.

Specifically, LED junction temperature is caused by two factors:

Internal quantum efficiency is not high, that is, when the electron and hole recombination, not 100% can produce photons, which is usually called "current leakage" to reduce the recombination rate of carriers in the PN region. The leakage current times the voltage is the power of this part, which is converted to heat, but it's not the main component, because the internal photon efficiency is now close to 90%.

That's the main part, because at the moment this so-called external quantum efficiency is only about 30 percent, and most of it is converted to heat.

As mentioned above, incandescent lamps have a very low light efficiency, only about 151m/W, but they convert almost all of the electric energy into light and radiate out. Because most of the radiation energy is infrared, the light efficiency is very low, but it avoids the problem of heat dissipation.

Solutions to heat dissipation of LED bulbs:

To solve the heat dissipation of LED bulb, we mainly start from two aspects. Before and after packaging, we can understand the heat dissipation of LED chip and LED bulb. LED chip heat dissipation is mainly related to the selection and process of substrate and circuit. This paper mainly introduces the heat dissipation of LED bulbs. Because any LED will be made into lamps, the heat generated by LED chips will always be dispersed into the air through the shell of lamps. Rayshower lighting believes that if the heat dissipation is not good, because the LED chip heat capacity is very small, a little heat accumulation will make the chip junction temperature quickly increase, if the long period of work in the high temperature state, its life will be quickly shortened. However, there are many ways for this heat to actually guide the chip out of the air. Specifically, the heat generated by the LED chip comes out of its metal cooling block, first through the solder to the aluminum substrate PCB, and then through the heat conduction glue to the aluminum radiator. Therefore, heat dissipation of LED hotel engineering lamps actually includes heat conduction and heat dissipation.