UV-A Blacklight - No Filter
The UV-A portion of the ultraviolet spectrum includes wavelengths from 315nm to 400nm. Commonly called blacklights, the UV-A bulbs in this category do not have a dark blue filter like other blacklight bulbs. The applications for the ultraviolet blacklight bulbs below include inspection, insect traps, curing, and phototherapy.
About Unfiltered UVA Blacklights
In contrast to filtered ultraviolet blacklights, these unfiltered versions do not block out the visible portion of the spectrum, although they retain strong emission peaks in the UVA range. The UVA range is defined to be between 315-400nm, and lamps emitting radiation in this range are used for a wide variety of specialty applications.
Commercial Insect Traps
Restaurants, grocery stores, and commercial kitchens often install fixtures using unfiltered blacklights. The ultraviolet light is attractive to flying insects, who enter the UV insect traps and are unable to escape. This makes for a healthier, cleaner environment in areas where food is being prepared or displayed.
Consumer Bug Zappers
Bug zappers often use small linear or compact UVA bulbs in the same application as the commercial traps. Instead of trapping the insects, though, bug zappers electrocute and vaporize the insects that enter the zapper.
The ultraviolet bulb does not itself cause the electrocution. Another component in the units provides that function. The UVA lamp attracts bugs to the device.
Commercial reprography machines utilize high output ultraviolet UVA lamps for quick curing of inks on printed documents. This can allow for printing on materials that would otherwise not be conducive to ink, like acrylic or aluminum.
The lamps used in these machines are high or very high output variations of UVA bulbs, but they are also often long lamps, from 4 to 6 feet, depending on the printing machine.
Unfiltered UVA bulbs are used in a wide variety of medical and healthcare applications. They can be used for low levels of ultraviolet disinfection of air, as well as for treating or detecting skin disorders.
Many of the bulbs used in such devices are small and designed to be used in small areas, like skin lesions, similar to how a handheld Woods lamp device is used to detect fungal infections on animals.
UVA lamps are used in commercial and consumer tanning beds and phototherapy fixtures. In tanning beds, the lamp is usually also designed to emit some UVB radiation.