Semiconductor light-emitting diodes produce heat – Gear Box – Ball Valve manufacturer

As with traditional light sources, semiconductor light-emitting diode (LED) will produce heat at work, their number depends on the overall luminous efficiency. Under an external electric energy, the radiative recombination of electrons and holes occurs EL, PN junction in the vicinity of the light radiated through the chip needed (chip) semiconductor media and packaging their own media to reach the outside (air). Integrated current injection efficiency, radiation quantum efficiency, light extraction efficiency of the external chip, only about 30-40% of the ultimate input energy into light, and the remaining 60-70% of the energy of a non-radiative recombination occurs lattice vibration the form of thermal energy conversion.

 

The chip temperature will increase non-radiative recombination, further weakening the luminous efficiency. Because it did not subjectively believe that high-power LED heat, and indeed there are. A lot of heat, so that in the course of a problem. Many first-time use of high-power LED with people who do not know how to heat problems are effectively addressed, making reliability a major problem. So, LED is there heat returned? How much heat can produce it? LED heat How much?

LED in forward voltage, electron gain energy from the power supply, driven by an electric field to overcome the PN junction of the electric field, the transition zone from the N to P zone, the electron and hole area occurred P composite. As the drift to the P region is higher than the P zone free-electron valence electron energy, combined with low energy state when the electronic return, the excess photon energy in the form of release. Given photon wavelength associated with the energy difference Eg. Can be seen mainly in the PN junction light-emitting area near the light electron and hole recombination due to the release of energy results. A semiconductor diode, electrons in the semiconductor area to leave the full distance in the semiconductor area, will encounter resistance. Simply from the principle point of view, the physical structure of the semiconductor diode simply from the principle point of view, the physical structure of the semiconductor diode cathode source of electrons and sent back to positive number of electrons are equal. Ordinary diodes, in the event of electron – hole on the composite, due to the energy gap Eg of the factors, the release of the photon spectrum is not in the visible range.

Electronic road within the diode, the resistance will be due to the presence of power consumption. The power consumed by the basic law of electronics meet:

P = I2 R = I2 (RN + + RP) + IVTH

The formula: RN is the N zone body resistance

VTH is a PN junction of the turn-on voltage

RP is the P zone body resistance

The power consumption of the heat generated is:

Q = Pt

The formula: t the time for the diode power.

Essentially, LED is still a semiconductor diode. Therefore, LED in the forward work, its work process meets the above description. It has its electric power consumption:

P LED = U LED × I LED

Type in: U LED is the forward voltage across the LED light source

I LED is the current flowing through the LED

The consumption of electric power into heat release:

Q = P LED × t

Type in: t for the power of time

In fact, the e-hole recombination in the P area and when the energy released is not provided directly by the foreign power, but because of the electron in the N zone, in the absence of external electric field, its energy level than the P region valence electron energy level higher than the Eg. When it reaches the P zone, and hole recombination and a P region of valence electrons, 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 external power supplies for electronic orientation doing it just to promote the movement, and to overcome the role of PN junction.

LED heat production has nothing to do with light effects; does not exist a few percent of the electrical power to generate light, and the remaining percentage of the relationship between the electric power generated heat. Heat through the generation of high power LED, thermal resistance, junction temperature and the theoretical understanding of the concept and formula of the thermal resistance measurement, we can study the actual high-power LED package design, evaluation and product applications. Be noted that the thermal management products in the LED luminous efficiency is not high at this stage of the key issues, and fundamentally improve the luminous efficiency to reduce heat generation is the drastic move, which requires chip, LED packaging and applications development The link technology.

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