Why does the LED lamp bead heat up

The reason why LED lamp beads generate heat is that not all the added electric energy is converted into light energy, but part of it is converted into heat energy. If the luminous efficiency of LED bulb is 100lm / W, its electro-optic conversion efficiency is only about 20 ~ 30%. In other words, about 70% of the electric energy is turned into heat energy.

Specifically, the junction temperature of LED lamp beads is caused by two factors:

1. The internal quantum efficiency is not high, that is, when electrons and holes combine, they can not produce 100% photons. It is usually called "current leakage", which reduces the recombination rate of carriers in PN region. The leakage current multiplied by the voltage is the power of this part, that is, it is converted into heat energy, but this part does not account for the main component, because the internal photon efficiency is now close to 90%.

2. The internal photons cannot all be emitted to the outside of the chip and finally converted into heat. This is the main reason, because at present, the so-called external quantum efficiency is only about 30%, and most of them are converted into heat.