An ultra-Violet light-emitting diode (UV LED) is a type of PN junction in which current flows from an Anode (positive side) to Cathode (negative side) and produces light. Each LED produces a specific narrow range of UV wavelength. UV LED light gained an important role in the post-Covid role because of its ability to kill germs.
Also, with minimal maintenance, instant on/off, small input power, better environmental protection, and a lifetime of over 20,000 hours, UV LED is a better option in lighting. The main types in terms of wavelength in UV LED light are:
- VUV light and wavelength <200 nm
- UVC Light and wavelength 200 to 280 nm
- UVB Light and wavelength 280 to 315 nm
- UVA Light and wavelength 315 to 480 nm
What is VUV Light?
Vacuum UV, also known as VUV, has a wavelength range of 10 to 200 nm. It can react immediately with oxygen atoms and organic molecules even at low doses, which is considered harmful. To work with this wavelength, you need evacuated equipment.
What is UVC Light?
This light is also called ultraviolet germicidal irradiation (UVGI) because it has biocidal effects. It is due to the range of wavelength in which it falls. The wavelength of UVC light is in the range of 200 to 280 nm.
What is UVB Light?
UVB light falls in the wavelength range of 280 to 315 nm. The photons in this wavelength are known for ‘Sun Burning’ of the skin and used in photo carcinogenesis and photo aging. They can also cause skin cancer because they play a proactive role in skin cancer formation.
What is UVA Light?
UVA light has a wavelength range of 315 to 400 nm. UVA1 wavelength ranges from 315 to 340 nm and has detrimental effects on the skin due to reactive oxygen species production.
UV light is usually considered an alternative to UV lamps because of many important features and updates due to the latest technology introduction. Here below, we are going to discuss the features of both UV lamps and UV LED lights.
The difference between UV Lamps and UV LED Sources
Traditional Arc lamps use an electric lamp inside a mercury gas to excite atoms, which then decay emitting photons. The bulb life in UV lamps is 500 to 2000 hours, and it requires bulb replacement and reflector cleaning in maintenance. Also, it dissipates more heat than UV LED sources.
In UV LED sources, current flows through the PN junction technique. The UV LED sources have a lifespan of over 20,000 hours, and they are environmentally friendly because they are Mercury and Ozone free. Also, heat dissipation is low, and it stays at around 60 Celsius.
UV LED light is slowly replacing the old lighting techniques and light as a disinfectant medium, but their applications are limited to those things. Here is a brief description of how LED lights can be used in different things.
Applications of UV LED Technology
- One of the applications of UV LED is the curing process. In this process, high-intensity UV light is used to instantly dry or cure coatings, inks, or adhesives. This process improves the solvency and scratch-resistance of the product.
- UV LED technology is widely used in spectroscopy because it provides real-time monitoring during the entire process, and it helps the doctors give accurate dosage to the patients.
- Water and air purification are done by UV LED lighting. It is done by killing biological impurities like viruses, bacteria, etc.
- In recent times, COVID-19 wreaked havoc in the world. Disinfection campaign in the world is led by UV LED lighting because it can effectively eliminate the virus. This disinfection is done by UVC LED light, and we will discuss it in detail in a later part of this article.
- UV sensors provide way better results than photoelectric sensors and machine vision systems. That is why UV-equipped sensors provide better gas detection, caps on bottles, labels, oil or coolant leaks, and other materials.
When Covid has changed the world forever, and there is no way back to the pre-Covid days, the importance of UV LED light has grown many folds because of its use as a disinfectant agent. UVC mainly does this function LED light, so we will discuss the use of UVC LED light in the war against Covid in detail but first, let us explore UVC in some detail to get an in-depth understanding.
How to Choose a UVC LED Light?
UVC LED lights usually fall in the range of 200 to 280nm. To achieve a shorter wavelength for the disinfection range (260 to 280nm), higher Aluminum friction is required, making the material’s growth and doping difficult. However, traditionally Sapphire is used as a substrate with a higher mismatching with the AlGaN structure of UVC LEDs. This mismatching leads to defects. So, to choose a better UVC LED light, a bulk lattice match AIN substrate should be used. This will allow higher efficiency and lower internal absorption.
What is the Best Wavelength For Disinfection by UVC LED Light?
According to the International Ultraviolet Association: “The portion of the UV spectrum that is important for the disinfection of water and air is the range that is absorbed by DNA and RNA in some viruses. This germicidal range is approximately 200-300nm.”
This germicidal range is what we call UVC LED light. There was a misconception about the optimum wavelength for disinfection, and it was set at 254nm. It was because of the peak wavelength of a low-pressure mercury lamp. However, it has been proved that the optimum wavelength for disinfection is 265nm because it is the peak of the DNA absorption curve.
So, the UVC LED light around the correct optimum wavelength, around 265nm, should be used for better results. It is because most of the germs have a peak absorption wavelength around 265nm.
You can check the UVC LED light’s effectiveness level to understand better which UVC LED light to choose. Here are the six levels of effectiveness of UVC LED light.
Different Levels of Disinfection and Effectiveness of UVC LED Light
There are mainly six levels of disinfection or effectiveness of UVC LED light. These levels are decided based on the reduction factor. With a population of one million bacteria, these six levels would be defined as:
- Reduce the colony to 100,000 bacteria – 90 per cent reduction
- Reduce the colony to 10,000 bacteria – 99 per cent reduction
- Reduce the colony to 1,000 bacteria – 99.9 per cent reduction
- Reduce the colony to 100 bacteria – 99.99 per cent reduction
- Reduce the colony to 10 bacteria – 99.999 per cent reduction
- Reduce the colony to one bacterium – 99.9999 per cent reduction
How UVC LED light is used to kill the novel Corona Virus?
Like all other viruses, Covid-19 is made up of unicellular organisms. One of the many ways to counter the Covid is by stopping the replication power and spreading by altering the virus’s DNA. When there are no new replications, there would be no new virions. In this way, the old one will die, and the spread is stopped.
So, UVC LED light can be used to incapacitate Corona Virus from surfaces, water, and even from the air, as reported by this article.
One thing must be kept in mind that UVC LED light can only be used to kill virions present on the surface, in water, or the air but cannot kill the virus in the human mouth or inside the human body. You have to use hand sanitizer or hand wash for 20 seconds to eliminate the germs on your skin. Using radiations for the disinfection purpose can cause damage to a person’s eyes and skin irritation.
UVC LED light can kill up to 99.9% of the germs. However, the effectiveness of UVC LED light depends on two factors.
The effectiveness of UVC LED light against Covid
There are two main factors on which the effectiveness of UVC LED light can be gauged. These are:
The simpler formula in the case of distance is that the closer you are to the surface of UVC LED light, the more effective it would be to eliminate the virus. However, in the case of 360 degrees UVC LED light, a threshold of a 6-inch radius is considered a standard. In this case, the classic example would be that hospitals use high-intensity UV lamps with a radius up to 6 feet to increase these lamps’ effectiveness for eliminating germs.
The longer the duration, the higher the disinfection. Also, it depends on the light intensity, which determines how far the effects of UVC LED light will be felt. If a high-intensity UVC LED light is used for a shorter duration or a low-intensity UVC LED light for a longer duration, they would have the same results. However, the high-intensity UVC LED light can have detrimental effects on human skin, so precautions must be placed while using high-intensity UVC LED light.
A standard UVC 270nm LED light can kill most germs in the six-inch radius in ten seconds.
Now, let us analyze how a minor mistake can cause an unpleasant situation while using UVC LED light.
Is UVC LED Light Harmful to Humans?
No. UVC LED light is not harmful to humans, but it can cause problems due to increased light intensity, closer proximity, etc. These are some of the problems it can cause to humans:
1. It can cause eye damage and skin damage.
Our body is made up of trillion of cells, and when UV light kills germs and microbes, our skin is also affected by this. Especially, eye pain is the common problem reported by people with excessive exposure to UV light. If the exposure exceeds a specific limit, it can cause cancerous cells and tumors, which can be fatal.
2. It can cause the formation of harmful Ozone gas.
Ozone gas is very volatile and can react with the organic materials in our body, which can have very negative consequences. It can cause several health complications like:
- Worsening respiratory diseases like Asthma
- Shortness of breath
- Chest pain
- Lung damage
- Throat irritations
To avoid these adverse effects, we can use customized UVC LED lights to ensure the balanced light intensity and on/off facilities.
Customization of UVC LED Light
A wavelength in the range of 260nm to 265nm is considered most effective in the disinfection process. However, disinfection can occur more efficiently at different wavelengths via different mechanisms like cell wall degradation. Light intensity, cost efficiency, and optimal wavelength should be kept in mind while choosing or customizing a UVC LED light for your home, hospital, shopping mall, etc. The switch button to turn UVC LED on or off should be placed at a point where everyone can access it and avoid the harmful effects of UVC LED light by timely switching the UVC LED on or off.
Why Should We Invest in UVC LED Light?
We should invest in UVC LED light because:
- They provide a cleaner and more convenient approach to disinfecting our environment.
- UVC LED light works way faster than any other disinfection technique and kills germs in a matter of minutes.
- Some of the UVC LED lights are portable and can disinfect certain places by quickly switching lights.
- You can minimize the health risk by maintaining the minimum distance from UVC LED light.
By concluding the article, UV LED light is one of the best sources to disinfect places quickly and easily. This is a very cost-effective way, and its importance has increased many folds in the aftermath of COVID-19. However, health hazards must be kept in mind, and certain safety precautions must be placed to ensure human safety.
You should consult an expert while installing UV LED light for a safer installation of LEDs.
For further information, you can contact us, and we will guide you about everything and every step while installing UV LED light.