uvled is ultraviolet light-emitting diode, is also a kind of LED, the wavelength range is: 10-400nm
uvled light-emitting mechanism.
PN junction terminal voltage constitutes a certain potential barrier, when adding a forward bias voltage when the potential barrier falls, the P and N regions of most carriers to each other diffusion. As the electron mobility than the hole mobility is much larger, so there will be a large number of electrons to the P region diffusion, constituting a minority of the P region carrier injection. These electrons and the valence band of the hole complex, complex energy obtained in the form of light energy released. This is the principle of PN junction luminescence.
uvled luminous efficiency.
Generally known as the external quantum efficiency of the component, which is the product of the internal quantum efficiency of the component and the component's take out efficiency. The so-called internal quantum efficiency of the component, in fact, is the component itself of the electro-optical conversion efficiency, mainly with the characteristics of the component itself (such as the component material energy band, defects, impurities), the component of the base crystal composition and structure and so on. The removal efficiency of the module refers to the number of photons generated inside the module, which can be measured outside the module after being absorbed, refracted and reflected by the module itself. Therefore, the factors concerning the extraction efficiency include the absorption of the component material itself, the geometry of the component, the refractive index difference between the component and the package material, and the scattering characteristics of the component structure. The product of the internal quantum efficiency of the module and the removal efficiency of the module is the luminous effect of the whole module, which is the external quantum efficiency of the module. Early module development focused on improving its internal quantum efficiency, the main method is to improve the quality of the base crystal and change the structure of the base crystal, so that electrical energy is not easily converted into heat, and thus indirectly improve the luminous efficiency of UVLED, so that about 70% of the theoretical internal quantum efficiency, but such internal quantum efficiency is almost close to the theoretical limit. In such a situation, it is impossible to improve the total amount of light of the module by improving the internal quantum efficiency of the module alone, so improving the removal efficiency of the module becomes an important research topic. The current method is mainly: the change of grain appearance - TIP structure, surface coarsening technology.
uvled electrical characteristics.
Current-controlled devices, load characteristics similar to the UI curve of the PN junction, a very small change in forward conduction voltage will cause a large change in forward current (exponential level), reverse leakage current is very small, with reverse breakdown voltage. In practice, should be selected . uvled forward voltage becomes smaller with increasing temperature, with a negative temperature coefficient. uvled consumes power , part of which is converted into light energy, which is what we need. The rest is converted into heat energy, which raises the junction temperature. The heat (power) dissipated can be expressed as .
uvled optical properties.
uvled provides a large half-width monochromatic light, because the energy gap of the semiconductor decreases with the rise in temperature, so the peak wavelength it emits grows with the rise in temperature, that is, the spectral redshift, the temperature coefficient of +2 ~ 3A / . uvled luminous brightness L with the forward current. Current increases, the luminous brightness also approximated to increase. In addition luminous brightness is also related to the ambient temperature, the ambient temperature is high, the compound efficiency decreases, the luminous intensity decreases.
uvled thermal characteristics.
Under small current, LED temperature rise is not obvious. If the ambient temperature is high, the main wavelength of uvled will be red-shifted, the brightness will decline, the uniformity and consistency of luminescence becomes poor. Especially dot matrix, large display temperature rise on the reliability and stability of the LED more significant impact. So thermal design is critical.