LED junction temperature is how did it?
LED fever because of the added electrical energy into light, and not all, but part of the conversion into heat. LED light efficiency is currently only 100lm / W, its electro-optical conversion efficiency of only about 20 to 30%. That is about 70% of the electrical energy into heat energy.
Specifically, LED junction temperature occurs due to two factors caused.
1. Internal quantum efficiency is not high, that is, when electrons and holes recombine and generate photons are not 100%, commonly referred to as the "current leakage" leaving the area PN carrier recombination rate decreases. Leakage current times voltage is this part of the power is converted into heat, but this part does not account for the main component, because the internal photon efficiency is close to 90%.
2. Internally generated photons emitted to the outside of the chip can not be all converted to heat and the last, which is the main part, referred to as the current external quantum efficiency of only about 30%, most of is converted into heat.
While incandescent light efficiency is very low, only 15lm / W or so, but it is almost all the electrical energy into light energy and radiate out, because most of the radiant energy is infrared, so the light efficiency is very low, but eliminating the problem of heat dissipation.