Ultraviolet lamp is a kind of light source that can produce ultraviolet light with a large effective range. In fact, there are often ultraviolet rays in general light sources, and the sun is the most prominent. The purple lamp bead in the ultraviolet lamp is a LED lamp bead that emits ultraviolet light, which can be used for ultraviolet sterilization, excitation of fluorescence (fluorescence microscope, currency check), trapping and killing insects, and printing pictures. The use of lower doses of ultraviolet radiation to cause non-lethal mutations caused by microorganisms can also be used as a means of microbial mutagenesis breeding. Ultraviolet rays can also turn oxygen in the air into ozone, which has a sterilizing effect.
Different UV wavelengths correspond to different uses. Next, I will talk about different UV wavelengths and their corresponding uses.
UVA (320～400nm): UV coating (UV ink, UV varnish, UV paint) UV glue curing. UV coating basically needs 395nm peak curing, 375nm and 385nm are also partially doped. The ideal peak value of UV glue is 365nm; UVA ultraviolet rays with a wavelength of 360nm conform to the phototaxis response curve of insects, and can be used to make insect trap lamps. UVA ultraviolet rays with wavelengths of 300-420nm can pass through special colored glass tubes that completely cut off visible light, and only emit near-ultraviolet light centered at 365nm, which can be used for ore identification, stage decoration, currency verification and other places.
Principle of UV LED lamp bead curing: Add a photoinitiator or photosensitizer to a specially formulated resin. After absorbing high-intensity ultraviolet light in the ultraviolet (UV) light curing equipment, active free radicals are generated, thereby initiating polymerization, cross-linking and The grafting reaction turns the resin from liquid to solid within a few seconds.
UVB (275～320nm): This kind of UV LED lamp beads are rare, and basically have no application. They exist in the form of UV tubes, which are low in cost and are used for plant growth. The peak value is about 295nm. Ultraviolet health lamps and plant growth lamps. What is emitted is made of special transparent purple glass (not transmitting light below 254nm) and phosphor with a peak around 300nm.
UVC (200～275nm): The UV peak value of this kind of UV LED lamp beads is usually 275nm, the ideal peak value should be 254nm, and the UV lamps are all 254nm, also known as short-wave sterilization ultraviolet rays are mainly used in the sterilization and disinfection industry, and ultraviolet germicidal lamps It emits UVC short-wave ultraviolet rays, which are widely used in hospitals, air-conditioning systems, disinfection cabinets, water treatment equipment, drinking fountains, sewage treatment plants, swimming pools, food and beverage processing and packaging equipment, food factories, cosmetics factories, and dairy products factories. , Breweries, beverage factories, bakeries and cold storage rooms.
The principle of ultraviolet sterilization: when organic pollutants pass through the ultraviolet radiation area, the ultraviolet rays will penetrate the cell membrane and cell nucleus of organisms. The ultraviolet rays are absorbed by the base pairs of DNA or RNA, and actin The activity of the genetic material of the cell is lost, and the microorganisms cannot reproduce or die soon. The indoor air disinfection machine has a cumulative effect on the microorganisms passing through its irradiation range, that is to say, the microorganisms that have not been killed when passing through the ultraviolet irradiation area for the first time will be killed in the subsequent cycle. Ultraviolet rays destroy the regenerative ability of organisms, which is very important. Because a bacterium can multiply hundreds or even millions of bacteria within 24 hours, this also means that even the most effective air filter cannot completely remove microorganisms, so ultraviolet sterilization is the cure for the root cause. The dose required for a microorganism to be killed by ultraviolet light depends on the intensity of the ultraviolet light and the irradiation time.
The UVD band, with a wavelength of 100-200nm, combines with oxygen to produce ozone.
Ozone sterilization principle: UVD ultraviolet rays with a wavelength of 185nm irradiate the air, which can decompose oxygen O2 molecules in the air, and the generated O atoms combine with O2 molecules to produce ozone O3. Ozone O3 has a strong oxidizing effect, which can destroy the cell wall of decomposing bacteria, and penetrate into the cell to oxidize and decompose to destroy the polymerization of glucose oxidase, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), protein, lipids, and polysaccharides. It destroys the metabolism and reproduction process of bacteria and kills them, and achieves the effect of sterilization and disinfection.
UVV (395-445nm) UV curing industry extends the band.
