The causes of technology | explanation LED junction temperature - China lighting network
The LED junction temperature for more than most people are not so familiar with, but even for the LED industry, and is that a clear, too! Now let's detailed explanation. LED is working, the following conditions can make junction temperature rise in different level. One, after a lot of practice has proved that the light efficiency limit is the main cause of the LED junction temperature rise high. At present, the advanced material growth and device fabrication process can make the LED most input energy converted to optical radiation can, however, due to the LED chip materials compared with surrounding medium, has a much larger refractive index, causing great part of the chip internally generated photons ( > 90%) Cannot smoothly overflow interface, and in total reflection and medium interface chip, the returned chip internal and through the multiple internal reflection eventually absorbed by chip material or substrate, and become hot, in the form of lattice vibration led junction temperature is high. Second, because of P - N junction can't extremely perfect, component injection efficiency does not reach 100%, when the LED work also that said, in addition P to N area charge injection ( Hole) To a P, N area will also note the charge ( Electronic) , under normal circumstances, the kind of charge after the one who is, won't produce the photoelectric effect, and consumed in the form of heat. Even if the useful part of the injected charge, also won't all become light, some of defects or precipitates and the junction area, the combination of will eventually become hot. Three electrode structure, components, Windows substrate structure or the materials and conductive silver glue have certain resistance, the resistance base with each other, constitute the LED the series resistance of the element. When current flows through the P - N junction, also flows through the resistor, resulting in a joule heat, the temperature or the rise of junction temperature caused by chip. Above is one of the main reasons that LED junction temperature, of course, does not rule out other chemical or physical phenomenon of those, of course, we still can't understand, but in the near future along with the advance of science and technology to learn technology, we can better explain the phenomenon, science with its magic will solve our confusion! YanZhiXiang
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