You may have heard so many mysteries about UV LEDs and how harmful they are. Are all of those remarks real? And here is also the most basic question: what is the UV LED? Are the nail lamps girls use in our daily life also UV LED lamps? Where can we use UV LEDs? To answer these questions, today I want to give you an overall view of UV LEDs. After reading this passage, you will form your own conception of UV LED. Let’s start right now.
Basic information about UV LED
UV means ultraviolet, and it is named so because this light is of a violet, or purple color. Unlike the visible light RGB LED creates, UV LED produces mainly invisible light. The reason why we can perceive violet color is that it can also emit a little visible violet light. The UV LED is a type of LED, and its illuminating principle is the same as that of common LEDs. A light-emitting diode consists of a ‘p-n junction’, and has unidirectional conductivity. When you apply a forward voltage to the light-emitting diode, the holes and the electrons react at both the P and N regions, resulting in the spontaneous emission of fluorescence. The energy generated by different semiconductor materials is different. The more energy released, the shorter the wavelength of light emitted.
Materials used to produce UV light are usually the III-V semiconductor ones, from aluminum nitride to gallium nitride or indium gallium nitride (InGaN). Their band gap falls between the blue light and ultraviolet light bands, so they can create these lights. To get ultraviolet and other visible light with different wave bands, we can change the ratio of the materials used. The wavelength of UV light ranges from approximately 200nm to 400 nm, while that of visible light is from 390nm to 780nm.
What are the differences between LED and UV LED
Many ladies who use nail lamps are concerned about the differences between LED and UV LED. The biggest difference is that UV LEDs emit UV light, while common LED lamps emit visible light. When it comes to the features of these two, there are other differences:
- UV light can cure all brands of phototherapy glue and nail polish, while LED light cannot cure phototherapy. And this is one point to which you need to pay attention when choosing a nail lamp.
- UV light can damage the eyes and skin to some extent, and long-term exposure may lead to carcinogenesis. LED belongs to ordinary light, and long-term use will not cause the risk of UV light.
- The UV lamp is a gas discharge lamp and needs to be replaced regularly. The LED lamp has a longer service life, so basically you don’t need to replace it for a long time.
- Compared with LED lamps, UV lamps consume more power and are more costly to use.
The UV light includes three types according to different wavelengths: UVA (400-315nm), UVB (315-280nm), UVC (280-100nm). Although all of them are emitted by the sun, their influence on us and their uses vary.
- UVA: Another name for UVA is “Blacklight”. 95% of the UV-A light penetrates the ozone layer and reaches the earth’s surface. It has the longest wavelength but contains the least energy among these three types. So it is relatively the safest. In our daily life, UVA is the most common ultraviolet light that we come into contact with. It exists almost at all the seasons and all the time of the day. It penetrates the glass and reach the second layer of our skin. UVA can cause skin problems such as sagging, wrinkles, and skin aging. At the same time, it accelerates the formation and deposition of melanin, making our skin darker.
UVA with different wavelengths can be useful in different fields. Uses of UVA include:
- Insect trap lamps apply the UVA light of 360nm wavelength.
- UVA between 390 nm and 350 nm works as the curing machine to cure adhesives, coatings, ink, and numerous other materials. The curing application of UVA is popular, as it is in demand for many industries like building materials, furniture, home appliances, automobiles, etc. Now this technique has become more and more mature.
- Ore identification
- Stage decoration
- Banknote detection
2.UVB: Only a small amount of UVB reaches the earth’s surface. But its wavelength is shorter and has more energy, so it is more harmful to our skin than UVA. UVB light is strongest in the summer or in the afternoon. It has a deeper influence on the skin than UVA. One advantages of it is promoting the metabolism of minerals and the formation of vitamin D in the human body. However, when exposed to high-intensity light for an extended period of time, problems such as sunburn and skin cancer can occur. People apply UVB in the following fields:
- Skin detection and treatment of skin diseases: UVB ultraviolet rays have an erythematous effect on the human body. So it can promote the metabolism of minerals and the formation of vitamin D in the body. This method belongs to physical therapy.
- Identify and detect unique materials: Using UVB light, it is possible to detect materials like nucleotides, proteins, fluorescent drugs, food additives, and fluorescent coatings.
- Grow lights for plants
3.UVC: Sometimes it can be notorious, other times famous. It is notorious because of its damage to human bodies. It is famous because it can be used for sterilization, which is needed by many people. Let us reveal its secrets right now.
UVC is the strongest type of UV light and has the shortest wavelength. Actually, the ozone layer absorbs almost all the UVC light, so it cannot reach us. The UVC light in our life comes from artificial lamps. When exposed to UVC, an erythematous reaction can be triggered on our skin. Besides, UVC radiation can cause acute inflammatory reactions of the cornea and conjunctiva in our eyes.
Below are the uses of UVC:
- Sterilization: UVC ultraviolet light destroys the DNA or RNA of the virus so that it can no longer reproduce and infect. It also destroys the protein covering the virus so that it cannot attach to the host cell. UVC can kill 99.9% of viruses and bacteria in air or water. Places like hospitals, public vehicles, schools, etc. make use of it. In the field of personal health and family hygiene, UVC can be useful for disinfection of water cups and chopsticks, air purification and sterilization, killing insects, sterilization and deodorization of shoes and socks, etc. There are products like LED UV portable devices, LED UV toothbrush sterilizers, and so on. In a world where people are committed to fighting the epidemic, this seems especially helpful.
- Military applications: Since the UVC band belongs to the sun-blind ultraviolet band, it also has important military applications, such as short-distance ultraviolet security communication, ultraviolet interference, and ultraviolet warning technology. Departments with high requirements for communication confidentiality and mobility value the use of it.
- Purification: The ultraviolet rays can work together with the oil and odor in the kitchen air and transform them into water and carbon dioxide without secondary pollution. The device is small, light, and can reduce fire hazards and maintenance costs.
- Food preservation: According to the literature, in terms of food preservation, UVC has demonstrated its excellent characteristics. Without other chemical reagents, only one deep ultraviolet LED lamp can increase the freshness of fruits and vegetables by 10-20 times at room temperature. In this way, it can reduce the loss to a greater extent.
Advantages of UV LED
People usually compare UV LED with the traditional mercury-vapor lamps, as it outperforms mercury UV lamps in the field of UV curing. Nowadays, UV LEDs have replaced lots of mercury UV lamps. And it has the following benefits:
- Energy-saving and low heat emission: UV LEDs can use 60%-70% less energy than common mercury UV lamps. This benefit comes from the fact that UV LED belongs to LED lights, so it has the same feature. LEDs transform most of the electricity into light, instead of heat. So less heat emission is also one of the advantages of UV LEDs.
- A long lifespan: Less heat emission contributes to a longer lifespan. It is less possible for the particles to break down because of too much heat. The common service life of UV LEDs can be up to 20,000 to 30,000 hours. Besides, there are not many particles in a LED circuit, which largely reduces the frequency of maintenance.
- Compact: There are many types of UV LED products. For example, there are UV LED flashlights that can create spotlights easily. For some equipment, UV LED components are also small enough for installation.
- Environmentally friendly: Unlike the mercury UV lights, it doesn’t contain mercury and doesn’t emit ozone. Whether a lamp will emit ozone or not depends on the wavelength of the light. Ultraviolet light with a wavelength shorter than 243 nm can excite oxygen in the air or water to produce ozone. Low-pressure mercury lamps will produce ozone because it naturally has 185nm vacuum ultraviolet rays in the luminescence spectrum. Common UVC-LED wavelengths are higher than 255 nm, so they won’t produce any ozone.
- High efficiency: UV LEDs can start working once you turn them on. In contrast, before using a mercury UV lamp, you need to warm it up. And the speed of UV LEDs used in the curing industry is much faster than that of traditional mercury lamps.
Despite its benefits, UV LED has its downsides. For example, because of its influence on our skin and eyes, operators of UV LED equipment must be clear about the precautions at first. When the devices are working, any other unrelated people should not enter the working place. Moreover, it is certain that the UV LED will be more costly with these premium functions.
Safety of UV LED
Safety is the top priority, and people are concerned about the side effects of UV LEDs. In the content above, we have mentioned some effects of UVA, UVB, and UVC on our skin and eyes. UV LED can be harmful to our bodies, but that doesn’t mean we should stop using it. Instead, we just need to keep the potential danger of it in mind and then use it after applying protective measures. Let us have a look at the side effects of LED and how to prevent them. (Note that the following content will only give you a general view of UV LEDs. For more detailed and accurate medical information, please advise your doctors.)
- To our skin: Short waves damage the epidermis of the skin; Medium waves can damage the dermis of the skin; Long waves have strong penetrating power and damage the cells below the dermis. These lead to metabolic disorders, immune system decline, dermatitis triggers, and even cancer. We must take it seriously. To minimize the risk, be sure to avoid exposing our skin to UV light. You can wear UV-protective clothing and hats. In our daily life, remember to wear sunscreen.
- To our eyes: Ultraviolet radiation can cause light ophthalmia, which can lead to conjunctivitis and keratitis; Electro-optic ophthalmia is based on light ophthalmia, and can induce cataracts. Some of these inflammations are curable. What we need to do to protect our eyes is wearing specialized glasses and avoid looking at the UV LED lamps directly. But it won’t do severe damage to your eyes if you are far enough from the lamp and haven’t stared at it for a long time. So sometimes, even though you have a look at the lamp accidentally, you can still be fine.
- About cancer: UVC LEDs destroy DNA or RNA to achieve the function of sterilization. As we humans also have DNA in our cells, it can have an influence on our bodies as well, especially on our skin. Researchers find the UV light used for nail lamps can lead to the death and mutation of cells. Therefore, always remember to equip yourself with PPE(personal protective equipment). While working with UV light, you can protect your face with UV goggles or full-face shields. For other exposed areas, lab coats, nitrile gloves, or other lab attire will help a lot.
With the development of technology, nowadays the PPE has become more and more professional. Moreover, many working areas need no operators. By using automatic machines, the whole process can be completed. So the influence of the safety problems of UV LEDs keeps decreasing.
The past and future of UV LED
In the early 1960s, visible LED lights appeared. The inventors then kept trying to change the ratio and type of the chip materials to get lights of different colors. From GaN LEDs to AlxGa1-xN LEDs, they finally made it so LEDs could produce invisible UV light. Here we will mention the evolution of UVC and UVA.
Scientists discovered the ability and application of UVC to kill viruses and bacteria in the 19th and 20th centuries. They call this method UVGI (ultraviolet germicidal irradiation). The study of it has lasted for many years. Scientists first tested the features of UVC, learning about how it can be safe and efficient. Then experts used it to treat several diseases, and it performed well in stopping the spread of some epidemics. Following researches tried to reduce the cost of its application to prompt its popularization.
In the past, mercury UV lamps were the mainstream products for creating UV light. Yet these days, people have higher aspirations for protecting the environment and ourselves. There are two main environmental hazards of the mercury light. First, mercury lamps will generate a large amount of ozone while working, which is bad for our health. Second, the service life of mercury lamps is relatively short, and the secondary pollution (mercury pollution) caused by discarded mercury lamps has always been a difficult problem to solve. With a UV LED, you don’t need to worry about these problems. Since their invention, UV LEDs have gone through an increase in voltage, an update to the chip, and a reduction in cost. With these benefits, they are replacing the mercury lamps on the market.
In terms of curing, UVA LEDs have basically completely replaced mercury lamps in the fields of electronic components, medical consumables, and other adhesive curing fields, as well as consumer curing fields represented by nail art curing. The future will witness the further application of UVA LED in many fields such as offset printing, silk screen printing, optical fiber coating, wood curing, and automobile curing.
In terms of disinfection and sterilization, the market favors air disinfection and flowing water treatment in small spaces or special areas. At present, home appliance disinfection occupies a large share of the UV LED market. The use of disinfection in public places has only recently begun. And large-scale industrial disinfection has begun to take shape. With the upgrading of technology, the application of UV LED will become more common.
At present, there are two main challenges for UV LEDs. The first is the low wall-plug efficiency (WPE), and it is urgent to overcome a series of problems, from core materials to chip technology to device packaging. The second is the need to expand the industry’s external influence, publicize and promote the concept of ultraviolet disinfection, and develop more new application scenarios and new customer groups. UV LEDs have great potential for development.
UV LED products of Mokolight
Here at Mokolight, we regard the production of UV LED as our mission to contribute to a better world. Most of our UV LED lights work for sterilization, and we have a variety of types that can be useful in the household, commercial, or industrial fields. Some representative products include the portable UV lamp, the UV troffer, and the industrial UV light. With 16 years of experience and a professional team, we try our best to produce safe and high-quality UV LED lights. If you want to make the places where you stay every day cleaner, don’t hesitate and click “Contact Us” right now!