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→LED
Before 2007, LEDs used less than 10% of the energy of an incandescent lamp, but did not produce as much light output per watt of energy consumed. To disguise this, some vendors rated LED efficiency as the amount of light output generated per watt of total output energy instead of the input energy.
However, ongoing research has dramatically improved the efficiency of LEDs; although this is only starting to appear in production versions. LED efficiency improved dramatically in 2006. Nichia Corporation of Japan demonstrated white LED prototypes with an efficiency of 113 lumens per watt. The industry target is 100 lumens per watt, which is better than fluorescent tubes. The Nichia work was partly funded by the UK Department of Trade & Industry. (White LEDs are actually blue in wavelengths of 450 nm – 470 nm.) In addition, LEDs produce no discernible heat and are more robust than fluorescents and incandescents. They LEDs have become the lighting of choice for many marine applications.
LEDs have a long life (100,000 hours) and low heat output. They give off a soft natural light in white, red, green or blue. White or blue are used for reading, e.g., a reading spot lamp. Red, green or blue are used for night vision.