The ultraviolet sterilization bands are 254nm, 275nm, 222nm, 405nm,
This band is commonly used in ultraviolet mercury lamps. It uses low-pressure mercury vapor to radiate ultraviolet rays during discharge. Low-pressure mercury vapor mainly produces 254nm and 185nm ultraviolet rays. The characteristic wavelength of the mercury lamp for sterilization is 253.7nm, and its radiation power reaches watts. (W) level, has a wide range of applications in a large space environment, and has a good sterilization effect.
In the past, ultraviolet mercury lamps were considered the best choice for disinfection and sterilization, including most germicidal lamps on the market today are still 254nm mercury lamps. However, compared with the ultraviolet LED lamp, the mercury lamp has the disadvantages of large size, high energy consumption, long warm-up time, and mercury content. In the future, deep ultraviolet LED will have a huge application space.
Deep ultraviolet LEDs are different from mercury lamps. The mainstream products of deep ultraviolet LEDs have characteristic wavelengths of 275-280nm. 253.7nm and 275nm are on both sides of the DNA absorption peak wavelength of 265nm respectively. They have almost the same DNA absorption value, so they have almost the same sterilization efficiency. .
UV LEDs have the advantages of small size, low power consumption, and instant on and on, etc., which can enclose ultraviolet rays in a small space. The leakage of ultraviolet rays is easy to prevent and control, and it can coexist with humans and machines. It has obvious advantages in practical applications. With the advancement of UV LED technology, UVC LEDs that are smaller, more powerful, non-toxic, longer-lived, more energy-efficient, and allow more switching times have become a new choice for sterilization light sources.
Researchers have found that ultraviolet rays with a wavelength of 222nm cannot penetrate the stratum corneum of human skin, are harmless to the human body, and have the same sterilization effect as traditional ultraviolet lamps. This is the actual situation.
The work is still in the laboratory research stage, and there is still a long way to go before industrial application.
The 405nm violet light (which can also be classified into the UVA range) has a certain sterilization ability. The researchers used a 18150mW 405nm light source to irradiate E. coli at a distance of 50cm for 9 hours to obtain a sterilization efficiency of 99.9%. This method has low sterilization efficiency, high light source power required, and difficult heat dissipation, which greatly limits its wide application.