Can UVLED kill virus? This question can give a clear answer: Yes. However, if you want to have a good anti-virus effect of UVLED, you have to choose the corresponding UVLED. UVLED devices have different effects according to different uses. For example, it's wrong to use the UV LED equipment for printing to disinfect. In medicine, it's also important to prescribe the right medicine to the case. There is a special UV LED equipment is used for disinfection, the effect is very good. The principle of UVLED antivirus is to use the characteristics of ultraviolet to achieve. UV wavelength is different, the effect of anti-virus is also different.

Ultraviolet disinfection belongs to the physical disinfection method. It can not kill microorganisms directly, but inactivate them by destroying their reproductive capacity. When a microorganism is exposed to ultraviolet radiation, its genetic material nucleic acid, DNA and RNA are destroyed by absorbing a large amount of ultraviolet energy, and lose the ability of division and replication. Finally, it will die naturally or be eliminated by the immune system, and lose the ability of pathogenicity to human body.

The visible spectral range of human eyes is generally 400-700nm. The electromagnetic wave with wavelength greater than 100nm and less than 400nm is called ultraviolet. After obtaining the energy, the outer electrons of atoms or molecules are excited and transition to the excited state. The electrons can not stay in the excited state and transition to the ground state. In this process, they radiate energy in the form of photons, namely ultraviolet.

According to the biological effect of UV, UV can be divided into four bands from high to low

UV-A (400-315nm): also known as black light, the longest wavelength, the lowest energy, occupies the largest share of ultraviolet light in nature. It can cause pigmentation of the skin to produce black spots, so it is also called black spot ultraviolet;

UV-B (315-280nm): it is the most destructive part of ultraviolet light in nature. It can cause skin sunburn and produce erythema. Part of it can be absorbed by the atmospheric ozone layer, also known as erythematous ultraviolet;

UV-C (280-200nm): completely absorbed by the atmosphere, usually only generated by artificial light source. It is used for sterilization and disinfection of ultraviolet rays with the wavelength of.

Vacuum ultraviolet (200-100nm): unable to enter the atmosphere, exists in space.

According to the research, the range of ultraviolet absorption spectrum of DNA and RNA of genetic material is 250-280nm. The traditional low-pressure mercury lamp has two main emission lines, 254nm and 185nm. Therefore, when the ultraviolet lamp wavelength is 254nm, the nucleic acid has the maximum absorption of ultraviolet, that is, the sterilization effect is the best.

With the development of the third lighting revolution caused by white LED solid-state lighting, people gradually turn their research focus to UV LED with high Al component group III nitrides as structural materials. UV LED has great application value in medical treatment, sterilization, printing, lighting, data storage, and secure communication. Compared with mercury lamp and hernia lamp, UV LED has strong advantages.

With the birth of ultraviolet light source, ultraviolet began to get real application. Gas discharge light source is the main form of traditional UV light source before the birth of deep UV LED. The spectrum radiation range of the gas discharge light source covers the ultraviolet region, the highest efficiency is 60%, and the lifetime is 100-1000 hours.

The gas discharge light source is mainly filled with argon and mercury vapor. According to the pressure of mercury vapor in the tube, mercury lamps are divided into low pressure, high pressure and ultra-high pressure mercury lamps. According to the different electrodes, low-pressure mercury lamp can be divided into hot cathode low-pressure mercury lamp and cold cathode low-pressure mercury lamp. Hot cathode mercury lamp is arc discharge lamp, which uses ternary salt oxide as cathode. Cold and hot cathode mercury lamp belongs to glow discharge lamp, which uses pure metal as cathode.

Composition of UVLED: it is composed of one or more InGaN Quantum Wells sandwiched in a thin Gan sandwich structure, and the active region formed is the cladding layer. By changing the relative ratio of inn Gan in the InGaN Quantum Well, the emission wavelength can be changed from purple light to other light. AlGaN can be used to fabricate the cladding layer and quantum well layer in UVLED by changing the AlN ratio, but the efficiency and maturity of these devices are poor. If the active quantum well layer is Gan, as opposed to InGaN or AlGaN alloy, the emission spectrum range of the device is 350 ~ 370nm.

When the short electron pulse at the pump of the blue InGaN led, ultraviolet radiation is generated. Aluminum nitrides, especially AlGaN and AlGaInN, can be used to fabricate devices with shorter wavelengths and obtain UVLED with a series of wavelengths. The diode with wavelength up to 247nm has been commercialized. The LED based on AlN and emitting 210nm ultraviolet radiation has been developed successfully. The UVLED with wavelength range of 250 ~ 270nm is also under development.

Compared with traditional gas ultraviolet light sources such as mercury lamp and hernia lamp, the new UV output light source UV LED has strong advantages

(1) The results show that the service life of mercury lamp is not affected by the opening and closing times, while the ultraviolet radiation intensity of mercury lamp decreases with the increase of the accumulated opening times and ignition time;

(2) Long service life, more than 20000 hours, traditional ultraviolet light source life of 100-1000 hours;

(3) The photoelectric conversion efficiency of traditional UV light source is 60%;

(4) Ultraviolet light accounts for more than 98% of all light output, and there is no infrared emission attached to traditional light source;

(5) It is small in size, only 0.1cm3 in volume, and can be assembled into various types of lamp arrays for different needs;

(6) The main peak is narrow and single: more than 90% of the optical output is concentrated in the range of ± 10 nm near the main peak;

(7) DC low voltage drive: suitable for portable UV equipment;

(8) The output power is stable and continuously adjustable;

(9) Instantaneous light: no preheating time is needed, and the response time is microsecond level;

(10) Environmental protection: no mercury, no heavy metal pollution.

Ultraviolet sterilization UV lamp can emit 253.7nm ultraviolet light, which is most easily absorbed by bacteria and virus proteins and nucleic acids. It can denaturate and dissociate proteins, form thymine dimer in nucleic acids, destroy DNA and RNA structures of various viruses and bacteria, and lead to the death of bacteria and viruses in a few seconds. The sterilization efficiency is as high as 99%, which can kill other disinfection methods Bacteria that cannot kill bacteria.

(1) Bacteria (more than 18 species), such as Escherichia coli, bacilli, Escherichia coli, Klebsiella, pulmonary tuberculosis, Neisseria, Salmonella, etc;

(2) Mold (more than 8 species), such as Penicillium, Niger, Mucor, fecal fungi, etc;

(3) Filter virus (more than 10 kinds), such as hepatitis virus, influenza virus, poliovirus, etc.

Since then, there has been a clear answer to whether UVLED can kill virus: UVLED can kill virus. Of course, UVLED has other uses.

Author: Liang Weiqing

Link: https://www.jianshu.com/p/af6404b4e056

Source: Jianshu

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