UV as everyone knows stands for Ultra Violet. It is actually a band of the light spectrum that is invisible to us. Most bulbs that we have now, produce some amount of UV rays, although the kind of bulb makes a difference. For example the High Intensity Discharge Xenon lamps are the highest emitters of ultra violet light and that is the reason why they are the closest when it comes to natural sunlight.
When you take pure ultraviolet bulbs, or black lights as they are sometimes called, they are just normal bulbs that have been painted with a substance that absorbs light in every other band other than the ultraviolet one. Although UV light is invisible, you can still see after a fashion, because the phosphorous around us starts to glow under UV. Even our clothes and teeth glow because the detergents and tooth paste have some amount of phosphorous in them.
The most popular example for the uses of UV light is as shown in television, where UV light is used to pick up traces of blood. Although this is true, this is not the reason for why we have UV lights. Greenhouses require quite a large number of UV bulbs because plants require sunlight in this wavelength to photosynthesize. Since most normal bulbs cannot give this required quantity of UV as most of them only emit in the visible band, UV bulbs are used.
Because of their high frequency UV light also has the tendency to travel much longer distances than normal light, and this is another reason for their use. In manufacturing sectors, UV light is used to identify flaws or blemishes in the product, and one of the best examples is in the use of UV light to examine the quality of manufacture of cars. UV tends to show up minute hairline cracks and other defects that may cause problems at a later date, and a computer controlled eye examines each welding point and rivet for signs of flaws. Even when examining the paint finish in cars, UV light is used because even imperfections that are invisible to the naked eye under ordinary light, tend to show up starkly under UV light.
UV also has bacteria killing properties and it is used in food packaging where all bacteria needs to be killed in order to ensure that the food keeps. Although the cooking process itself is sufficient to do this the UV light is the last link in the chain that will ensure that there is nothing remaining. The problem is that until now UV light could be obtained only using incandescent bulbs. Incandescent bulbs have a life of only around 750 hrs which means that you will be going through a lot of bulbs in a month. With the advent of UV LED bulbs this problem is solved. LEDs are very durable and are known to last even longer than fluorescent bulbs which itself lasts 20,000 hrs. The savings in terms of cost is tremendous, especially in those industries that require a lot of use of UV light.
Another good thing about UV LEDs is that they do not consume much power. Their electricity consumption is to the order of just around 15% of normal incandescent bulbs. This means that you can pretty much use 6 bulbs where there was one initially, or save six times the power. In fact LED bulbs are so efficient that many times they can last the entire night on just the batteries alone. Their small size also makes them very portable and if you have a UV LED torch you can carry it around with you just like an ordinary one. In fact these torches even come with a filter that can be attached over the torch so that when you want a normal torch, you take it off, and put it back on when you want UV light. Cool isn’t it.