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Floodlights are broad-beamed, high-intensity artificial lights. They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions. More focused kinds are often used as a stage lighting instrument in live performances such as concerts and plays. In the top tiers of many professional sports, it is a requirement for stadiums to have floodlights to allow games to be scheduled outside daylight hours. Evening or night matches may suit spectators who have work or other commitment earlier in the day. The main motivation for this is television marketing, especially in sports such as gridiron football which rely on TV rights money to finance the sport. Some sports grounds which do not have permanent floodlights installed may make use of portable temporary ones instead. Many larger floodlights (see bottom picture) will have gantries for bulb changing and maintenance. These will usually be able to accommodate one or two engineers. == Types == The most common type of floodlight is the metal-halide lamp, which emits a bright white light (typically 75-100 lumens/Watt). Sodium-vapor lamps are also commonly used for sporting events, as they have a very high lumen-to-watt ratio (typically 80–140 lumens/Watt), making them a cost-effective choice when certain lux levels must be provided.〔(【引用サイトリンク】url=http://www.webcitation.org/6SgspoCES )〕 In the recent years there have been new developments, and LED technology has come a long way. Now LED flood lights are bright enough to be used for illumination purposes on large sport fields.〔("Flood light types" ), www.ledsolarfloodlights.com〕 The main reason for the use of LEDs is the lower power consumption and the fact that LED bulbs last longer. The first LED lit sports field in the United Kingdom was switched on at Taunton Vale Sports Club on 24 March 2014. 〔http://www.sportengland.org/media/694946/taunton-taunton-vale-sports-club.pdf〕 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「floodlight」の詳細全文を読む スポンサード リンク
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