REVIEW: LED forward voltage, electrons from the power get energy to overcome the electric field of the PN junction in the electric field driven transition from the N region to the P region, the Electronics and P area hole composite.
Keyword the LED 200W PN junction integrated current injection efficiency of the luminescent quantum efficiency of the chip external light extraction efficiency, and ultimately probably only 30-40% of the input electrical energy into light energy, the remaining 60-70% of the energy of the main non-radiative recombination occurred of lattice vibrations in the form of conversion of thermal energy.
Chip temperature will enhance the non-radiative recombination, further weaken the luminous efficiency. High-power LED 400W no heat, and indeed there are, it is subjective. A lot of heat, so that in the course of a problem. In addition, many of the initial use of high-power LED thermal problems they do not understand how to effectively resolve product reliability as a major problem. So, LED is there heat generation? Can produce how many calories? LED heat generated by how much?
LED Floodlight 80W forward voltage, electrons from the power gain energy, driven by the electric field, to overcome the electric field of the PN junction by N region transition to the P region, these electrons and P area hole occurrence of the composite. Free electrons drift to the P region is higher than the P valence electrons in the energy, the compound when the electrons return to lower energy state, the excess energy released in the form of photons. The emitted photon wavelength and energy difference Eg. Visible emitting area near the PN junction, luminous as a result of the electron and hole recombination energy release. A semiconductor diode, electronics of all journeys into the semiconductor area to leave the semiconductor area, will encounter resistance. Simply from the principle point of view, the physical structure of the semiconductor diode is simply from the principle point of view, the physical structure of the source of semiconductor diode anode issued electronic and back to the positive number of electrons are equal. Ordinary diode, in the event of electron - hole pair of composite factors due to the energy gap Eg, the release of the photon spectrum is not in the visible range.
In fact, the energy released by the electrons in the P region and hole recombination, not by the external power supply provided directly, but because the electrons in the N region, in the absence of external electric field, its energy level than the P zone valence electron energy level higher than Eg. When it reaches the P region, the P region of the valence electron and hole recombination, it will release so much energy. Eg size is determined by the material itself, has nothing to do with the external electric field. The role of the external power supply for electronic only push it to do directional movement, and to overcome the PN junction.
The heat production of the LED Blue 150W luminous efficiency has nothing to do; does not exist a few percent of the electric power to produce light, the remaining few percent of the electric power to produce a hot relationship. Heat generated by high-power LED thermal resistance, junction temperature of the concept of understanding and theoretical derivation of the formula and thermal resistance measurements, we can study the actual high-power LED package design, evaluation, and product applications. Should be noted that heat management is a key issue in the luminous efficiency of LED products is not high at this stage, and fundamentally improve the luminous efficiency to reduce the heat generated is drastic move, which requires a chip manufacturing, LED strip lights packaging and application product development various aspects of advances in technology