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Plasma lamps are a type of gas discharge lamp energized by radio frequency (RF) power. They are distinct from the novelty plasma lamps that were popular in the 1980s. The internal-electrodeless lamp was invented by Tesla after his experimentation with high-frequency currents in evacuated glass tubes for the purposes of lighting and the study of high voltage phenomena. The first practical plasma lamps were the sulfur lamps manufactured by Fusion Lighting. This lamp suffered a number of practical problems and did not prosper commercially. These problems have gradually been overcome by manufacturers such as Ceravision and Luxim, and ''high-efficiency plasma'' (HEP) lamps have been introduced to the general lighting market. Plasma lamps with an internal phosphor coating are called external electrode fluorescent lamps (EEFL); these external electrodes or terminal conductors provide the radio frequency electric field. ==Description== Modern plasma lamps are a family of light sources that generate light by exciting plasma inside a closed transparent burner or bulb using radio frequency (RF) power. Typically, such lamps use a noble gas or a mixture of these gases and additional materials such as metal halides, sodium, mercury or sulfur. In modern plasma lamps, a waveguide is used to constrain and focus the electrical field into the plasma. In operation, the gas is ionized, and free electrons, accelerated by the electrical field, collide with gas and metal atoms. Some atomic electrons circling around the gas and metal atoms are excited by these collisions, bringing them to a higher energy state. When the electron falls back to its original state, it emits a photon, resulting in visible light or ultraviolet radiation, depending on the fill materials. The first commercial plasma lamp was an ultraviolet curing lamp with a bulb filled with argon and mercury vapor developed by (Fusion UV ). That lamp led Fusion Lighting to the development of the sulfur lamp, a bulb filled with argon and sulfur that is bombarded with microwaves through a hollow waveguide. The bulb had to be spun rapidly to prevent it burning through. Fusion Lighting did not prosper commercially, but other manufacturers, such as LG Group, continue to pursue sulfur lamps. Sulfur lamps, though relatively efficient, have had a number of problems, chiefly: #Limited life – Magnetrons had limited lives. #Large size #Heat – The sulfur burnt through the bulb wall unless they were rotated rapidly. #High power demand – They could not sustain a plasma in powers under 1000W. 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「Plasma lamp」の詳細全文を読む スポンサード リンク
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