Everyone knows that UVC LED has a significant sterilization and disinfection effect. At a certain dose and distance, it takes only a few seconds to tens of seconds to kill common bacteria. But what we do n’t know is that, with the fierce market, various UVC LED application products on the market came into being, but the actual use effect is very different, all in all, it is the difference between technology and process.
Heat dissipation is the key to improve the life of UV LED, like any electronic component, UVC LEDs are sensitive to heat.
The external quantum efficiency (EQE) of UVC LEDs is low. About 1-3% of the input power is converted into light, and the remaining 97% is basically converted into heat. At this time, if the heat is not removed quickly, keeping the LED chip below its maximum operating temperature will directly affect the service life of the chip, and even cannot be used. Therefore, thermal management is the key to improving the service life of UVC LEDs.
Due to the small size of UVC LEDs, most of the heat cannot be dissipated from the surface, so the back of the LED has become the only way to effectively dissipate heat. At this time, how to do thermal management on the encapsulated joints is particularly important..
In terms of materials, after years of development, the current UVC LED market is basically based on the flip chip with high thermal conductivity aluminum nitride substrate. Aluminum nitride (AIN) has excellent thermal conductivity (140W/mK-170W/mK), can withstand the aging of the ultraviolet light source itself, and meet the needs of UVCLED high thermal management.
In terms of process, there are several ways of solid crystals on the market. The first is to use silver paste. Although this method has a good binding force, it is easy to cause silver migration and lead to device failure. The second is soldering with solder paste. In this method, since the melting point of the solder paste is only about 220 degrees, after the device is mounted, re-melting will occur again after the furnace, the chip is easy to fall off and fail, affecting the reliability of UVC LED. Therefore, the third type of solid crystal is mostly used on the market: gold-tin eutectic welding. Compared with the first two methods of solid crystal bonding, its eutectic welding mainly uses flux, which can effectively improve the bonding strength of chip and substrate, thermal conductivity, more reliable, and is conducive to the quality control of UVC LED.
IBT LED focus on the manufacture of UVC LEDs, providing reliable and solid UVC LED products.
Date: 12-May-2020