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A germicidal lamp is a special type of lamp which produces ultraviolet light (UVC). This short-wave ultraviolet light disrupts DNA base pairing causing thymine-thymine dimers leading to death of bacteria on exposed surfaces. It can also be used to produce ozone for water disinfection. There are two common types available: * Low pressure lamps * Medium pressure lamps ==Low pressure lamps== Low-pressure lamps are very similar to a fluorescent lamp, with a wavelength of 253.7 nm (1182.5 THz). The most common form of germicidal lamp looks similar to an ordinary fluorescent lamp but the tube contains no fluorescent phosphor. In addition, rather than being made of ordinary borosilicate glass, the tube is made of fused quartz. These two changes combine to allow the 253.7 nm ultraviolet light produced by the mercury arc to pass out of the lamp unmodified (whereas, in common fluorescent lamps, it causes the phosphor to fluoresce, producing visible light). Germicidal lamps still produce a small amount of visible light due to other mercury radiation bands. An older design looks like an incandescent lamp but with the envelope containing a few droplets of mercury. In this design, the incandescent filament heats the mercury, producing a vapor which eventually allows an arc to be struck, short circuiting the incandescent filament. At the last two decades the rapid development is acquired so-called excimer lamps having a number of advantages over the other sources of ultraviolet and even vacuum ultraviolet radiation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Germicidal lamp」の詳細全文を読む スポンサード リンク
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