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The internal electrodeless lamp or induction light is a gas discharge lamp in which the power required to generate light is transferred from outside the lamp envelope to the gas inside via an electric or magnetic field, in contrast with a typical gas discharge lamp that uses internal electrodes connected to the power supply by conductors that pass through the lamp envelope. There are three advantages to elimination of the internal electrodes: * Extended lamp life, because the internal electrodes are usually the limiting factor in lamp life. * The ability to use light-generating substances of higher efficiency that would react with internal metal electrodes in normal lamps. Two systems are described below – plasma lamps, which use electrostatic induction to energize a bulb filled with sulfur vapor or metal halides, and fluorescent induction lamps, based upon a conventional fluorescent lamp bulb in which current is induced by an external coil of wire via electrodynamic induction. ==History== In 1705, the scientist Francis Hauksbee demonstrated that in a rotating glass globe with internal vacuum like in a barometer, filled with mercury, and statical charged by holding a hand against the rotating globe, a light phenomenon occurred, so bright that one could read a paper. Nikola Tesla demonstrated wireless transfer of power to electrodeless lamps in his lectures and articles in the 1890s, and subsequently patented a system of light and power distribution on those principles.〔("Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination", AIEE, Columbia College, N.Y., May 20, 1891 )〕 In 1967 and 1968, John Anderson of General Electric〔(Electrodeless gaseous electric discharge devices utilizing ferrite cores )〕〔(High frequency electrodeless fluorescent lamp assembly )〕 applied for patents for electrodeless lamps. In 1971, Fusion UV Systems installed a 300-watt electrodeless microwave plasma UV lamp on a Coors can production line.〔(A History of Heraeus Noblelight Fusion UV and its Industry Leadership in UV Curing Equipment and Products )〕 Philips introduced their ''QL'' induction lighting systems, operating at 2.65 MHz, in 1990 in Europe and in 1992 in the US. Matsushita had induction light systems available in 1992. Intersource Technologies also announced one in 1992, called the ''E-lamp''. Operating at 13.6 MHz, it was to be available on the US market in 1993. In 1990, Michael Ury, Charles Wood and colleagues formulated the concept of the sulphur lamp. With support from the United States Department of Energy, it was further developed in 1994 by Fusion Lighting of Rockville, Maryland, a spinoff of the Fusion UV division of Fusion Systems Corporation. Its origins are in microwave discharge light sources used for ultraviolet curing in the semiconductor and printing industries. Since 1994, General Electric has produced its induction lamp ''Genura'' with an integrated ballast, operating at 2.65 MHz. In 1996, Osram started selling their ''Endura'' induction light system, operating at 250 kHz. It is available in the US as the Sylvania ''Icetron''. In 1997, PQL Lighting introduced in the US the ''Superior Life Brand'' induction lighting systems. Most induction lighting systems are rated for 100,000 hours of use before requiring absolute component replacements. In 2005, Amko Solara in Taiwan introduced induction lamps that can dim and use IP (Internet Protocol) based controls. Their lamps have a range from 12 to 400 watts and operate at 250 kHz. From 1995, the former distributors of Fusion, Jenton / Jenact, expanded on the fact that energised UV-emitting plasmas act as lossy conductors to create a number of patents regarding electrodeless UV lamps for sterilising and germicidal uses. Around 2000, a system was developed that concentrated radio frequency waves into a solid dielectric waveguide made of ceramic which energized a light-emitting plasma in a bulb positioned inside. This system, for the first time, permitted an extremely bright and compact electrodeless lamp. The invention has been a matter of dispute. Claimed by Frederick Espiau (then of Luxim, now of Topanga Technologies), Chandrashekhar Joshi and Yian Chang, these claims were disputed by Ceravision Limited.〔(Ceravision Steps up Legal Action Against Luxim to Recover IP )〕 A number of the core patents were assigned to Ceravision.〔(Microwave Energized Plasma Lamp with Solid Dielectric Waveguide )〕〔(Plasma Lamp with Dielectric Waveguide )〕 In 2006, Luxim introduced a projector lamp product trade-named LIFI. The company further extended the technology with light source products in instrument, entertainment, street, area and architectural lighting applications among others throughout 2007 and 2008. In 2009, Ceravision Limited introduced the first High Efficiency Plasma (HEP) lamp under the trade name Alvara. This lamp replaces the opaque ceramic waveguide used in earlier lamps with an optically clear quartz waveguide giving greatly increased efficiency. In previous lamps, though the burner, or bulb, was very efficient, the opaque ceramic waveguide severely obstructed the collection of light. A quartz waveguide allows all of the light from the plasma to be collected. In 2012, Topanga Technologies introduced a line of advanced plasma lamps (APL), driven by a solid state radio frequency (RF) driver,〔(Topanga :: Home )〕 thereby circumventing the limited life of magnetron-based drivers, with system power of 127 and 230 watts and system efficacies of 96 and 87 lumen/watt, with a CRI of about 70. 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「electrodeless lamp」の詳細全文を読む スポンサード リンク
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