Black Light Classification and Application
A black light is a lamp that emits electromagnetic radiation almost exclusively in the soft near ultraviolet range. Only a very small fraction of visible radiation passes through the filtering material, with wavelengths no longer than 400-410 nm, and as a result, the human eye detects its color as deep blue and violet. Wood’s glass is an example of filtering material which is transparent to ultraviolet wavelengths between 320 and 400 nm.
Black light sources may be made from specially designed fluorescent lamps, mercury vapor lamps, light-emitting diodes, or incandescent lamps. In most black lights either the glass envelope of the lamp itself or the lamp enclosure has an optical filter designed to reduce the emission of visible light and pass desired parts of the ultraviolet spectrum. In medicine, forensics, and some other scientific fields, such a light source is referred to as a Wood’s lamp.
Classification
According to the light source type, it can be divided into high-pressure mercury lamp, fluorescent low pressure mercury lamp and metal halide lamp black lights three categories.
According to the power supply, it can be divided into AC power black lights and DC power supply black lights two kinds.
According to the appearance, it can be divided into tube-type black lights and incandescent black light.
Application
Black light sources have many uses. They may be employed for decorative and artistic lighting effects, for diagnostic and therapeutic uses in medicine, for the eradication of microorganisms, for the observation or detection of substances tagged with other substances that exhibit a fluorescent effect, for the curing of plastic resins and for attracting insects. Strong sources of long-wave ultraviolet light are used in tanning beds. Black light lamps are used for the detection of counterfeit money. Most artificial ultraviolet sources are low power. Powerful ultraviolet sources present a hazard to eyes and skin; apparatus using these sources requires personal protective equipment.