What is UV LED

UV LED Basic knowledge

Wavelength classification and application of ultraviolet

According to the different biological effects, ultraviolet can be divided into four bands: long wave UVA, medium wave UVB, short wave UVC and vacuum wave UVD. The longer the wavelength, the stronger the penetration.

UVA

Long wave UVA, wavelength between 320 ~ 400 nm, also known as long wave black spot effect ultraviolet. It has strong penetrating power and can penetrate glass, even 9 feet of water; And all the year round, whether it’s sunny or sunny, day and night.

Degree of harm to human body: more than 95% of the ultraviolet rays that the daily skin is exposed to are UVA, so it is the most harmful to the skin. UVA can attack the dermis through the epidermis and severely damage the collagen and elastin in the skin; Moreover, the self-protection ability of dermal cells is poor, and a small amount of UVA can cause great damage. Over time, skin relaxation, wrinkles, microvascular emergence and other issues.

At the same time, it can activate tyrosinase, leading to immediate melanin deposition and new melanin formation, making the skin black and lack luster. UVA can cause long-term, chronic and lasting damage, making the skin aging prematurely, so it is also known as aging rays.

Application: UVA ultraviolet with wavelength of 360nm conforms to the phototaxis response curve of insects, and can be used to make insect traps. The UVA ultraviolet with the wavelength of 300-420nm can pass through the special colored glass lamp which completely cuts off the visible light, and only radiates the near ultraviolet light with the center of 365nm. It can be used in ore identification, stage decoration, banknote verification and other places.

UVB

Medium wave UVB, wavelength between 275 ~ 320 nm, also known as medium wave erythema effect ultraviolet. Medium penetration, the shorter part of its wavelength will be absorbed by transparent glass, most of the UVB contained in sunlight will be absorbed by the ozone layer, and only less than 2% can reach the earth’s surface, which will be particularly strong in summer and afternoon.

Degree of harm to human body: it will oxidize the protective lipid layer of the skin and make the skin dry; Further, the nucleic acid and protein in the epidermal cells denatured, resulting in acute dermatitis (that is, sunburn) and other symptoms, the skin will become red and painful. Serious, such as long-term exposure, but also easily lead to skin cancer. In addition, the long-term damage of UVB can also cause the mutation of melanocytes, resulting in the sun spot which is difficult to eliminate.

Application area: ultraviolet health lamp, plant growth lamp is issued by using special violet glass (not light below 254nm) and the peak value of phosphor near 300nm.

UVC

Short wave UVC, wavelength between 200 ~ 275 nm, also known as short wave sterilization ultraviolet. Its penetration ability is the weakest, unable to penetrate most of the transparent glass and plastic. The shortwave ultraviolet rays contained in sunlight are almost completely absorbed by the ozone layer, and are absorbed by the ozone layer before reaching the ground.

Degree of harm to human body: UVC in nature is absorbed by the ozone layer before reaching the ground, and its impact on the skin can be ignored, but in fact, the harm of short wave ultraviolet to human body is very big, and it can not directly irradiate the human body. If direct irradiation, short-term irradiation can burn the skin, long-term or high-intensity irradiation can also cause skin cancer.

Application field: ultraviolet germicidal lamp emits UVC short wave ultraviolet light. Shortwave ultraviolet is 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, dairy products factories, breweries, beverage factories, bakeries and refrigerators.

Advantages and disadvantages of UV

Advantages of ultraviolet:

1) disinfection and sterilization,

2) Promote bone development,

3) It is good for blood color,

4) Occasionally, it can treat some skin diseases,

5) It can promote the metabolism of minerals and the formation of vitamin D.

Disadvantages of UV:

1) aging skin and wrinkles,

2) Producing spots,

3) Cause dermatitis,

4) Cause skin cancer.

Knowledge of UVC ultraviolet

Sterilization principle of UVC

Among all wavelengths of UV, only short wave UV UVC has bactericidal effect

It is a pure physical disinfection method with broad spectrum, high efficiency, fast and thorough, no need to add chemicals

There is no drug resistance, no secondary pollution and other characteristics.

UVD ultraviolet with wavelength of 185nm can change oxygen O2 into ozone O3 in the air. Ozone has strong oxidation effect and can effectively kill bacteria, but ultraviolet with wavelength of 185nm has no bactericidal effect. The dispersion of ozone can just make up for the shortcomings that ultraviolet can only spread in a straight line and disinfection has a dead angle. It can reach any corner of the space with the air and make sterilization more thorough.

Principle of ultraviolet sterilization: irradiate bacteria, viruses and other microorganisms with ultraviolet rays to destroy bacteria

The molecular structure of DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) in body cells causes DNA strand breaks, nucleic acid and protein cross-link breaks, leading to the death of growing cells and regenerative cells, achieving the effect of sterilization. Among them, ultraviolet rays with a wavelength of 253.7nm are the best.

Ozone sterilization principle: ultraviolet radiation of 185nm wavelength UVD can decompose oxygen O2 molecules in the air, and the generated O atoms can combine with O2 molecules to produce ozone O3. Ozone O3 has strong oxidation effect, which can destroy the cell wall of bacteria, penetrate into cells, oxidize and decompose glucose oxidase, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), protein, lipid, polysaccharide macromolecular polymers, destroy the metabolism and reproduction process of bacteria and die, so as to achieve the effect of sterilization and disinfection.

terilization characteristics of UVC

High efficiency sterilization: the sterilization effect of ultraviolet on bacteria and virus is generally completed in a few seconds, almost instantaneous, and the sterilization and disinfection ability is 600-3000 times greater than that of chlorine.

Broad spectrum of sterilization: ultraviolet technology in all the current disinfection technology, the broad spectrum of sterilization is the highest. It can kill almost all bacteria and viruses efficiently.

More thorough sterilization: UV combined with ozone (UVC + O3), can play a more powerful and thorough sterilization power. Ultraviolet rays irradiate the air and the surface of objects in a straight line to achieve strong sterilization; Ozone permeates into every corner of the room with the air, killing indoor bacteria completely.

Complete environmental protection: ultraviolet light is used for sterilization and disinfection. Ultraviolet light irradiates oxygen in the air to generate ozone. Ozone strongly oxidizes and kills bacteria and viruses. No chemical agent is added in the whole sterilization process, which truly achieves complete environmental protection.

There is no drug resistance: UV or ozone directly destroy DNA, RNA, protein, etc. in bacterial virus cells, causing direct cell death and unable to reproduce, so there is no drug resistance. However, the sterilization of other chemicals will make bacteria and viruses resistant to antibiotics, resulting in the invalidation of the chemical sterilization effect.

No secondary pollution: UV, ozone caused direct death of bacteria and viruses, no other chemical pollutants; At the same time, ozone is converted into oxygen in 15-30 minutes (ozone half-life) at room temperature without any residual secondary pollution.

Prevent UVC from damaging human body

The main parts of human body injured by ultraviolet radiation(UVC) are eyes and naked skin. Short term high-intensity radiation can burn eyes and skin, and long-term high-intensity radiation can even cause skin damage or skin cancer.

UVC ultraviolet penetration is very weak, ordinary transparent glass, clothing, plastic, dust, etc. can completely block. So wear glasses (avoid looking directly at the UV lamp if you don’t have glasses)

to cover the naked skin with clothes as much as possible to protect the eyes and skin from UVC ultraviolet rays.

Short time exposure to ultraviolet light is just like exposure to the sun. It is not harmful to the human body, but beneficial. Ultraviolet B can promote the metabolism of minerals and the formation of vitamin D in the body.

The principles to prevent UVC ultraviolet damage are as follows:

1) wear glasses (ordinary glass or resin lenses are OK),

2) Avoid looking directly at the ultraviolet lamp,

3) Wear long sleeve clothes to cover bare skin such as hands,

4) Use objects around to block ultraviolet rays, such as walls, furniture, curtains, books, newspapers, etc,

5) Avoid long-term ultraviolet radiation, short-term radiation does not harm the human body.