The incandescent light bulb or lamp is a source of electric light that works by incandescence, which is the emission of light caused by heating the filament. Incandescent bulbs are the original form of electric lighting and have been in use for over 100 years. While Thomas Edison is widely considered to be the inventor of the incandescent bulb, there are a number of people who invented components and prototypes of the light bulb well before Edison did.
An incandescent bulb typically consists of a glass enclosure containing a tungsten filament. An electric current passes through the filament, heating it to a temperature that produces light. Incandescent light bulbs usually contain a stem or glass mount attached to the bulb's base which allows the electrical contacts to run through the envelope without gas/air leaks. Small wires embedded in the stem support the filament and/or its lead wires. The enclosing glass enclosure contains either a vacuum or an inert gas to preserve and protect the filament from evaporating.
Incandescent lamps are often considered the least energy efficient type of electric lighting commonly found in residential buildings. Although inefficient, incandescent lamps possess a number of key advantages--they are inexpensive to buy, turn on instantly, are available in a huge array of sizes and shapes and provide a pleasant, warm light with excellent color rendition.Despite the advantages, there have been restrictions on the sales of the light bulbs.
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| Incandescent Light Bulbs |
Are they making a comeback?
Scientists in the US believe they have come up with a solution which could see a reprieve for incandescent bulbs.
Researchers at MIT have shown that by surrounding the filament with a special crystal structure in the glass they can bounce back the energy which is usually lost in heat, while still allowing the light through.
They refer to the technique as ‘recycling light’ because the energy which would usually escape into the air is redirected back to the filament where it can create new light.
"It recycles the energy that would otherwise be wasted," said Professor Marin Soljacic.
An energy efficient light bulb
Usually traditional light bulbs are only about five per cent efficient, with 95 per cent of the energy being lost to the atmosphere. In comparison LED or florescent bulbs manage around 14 per cent efficiency. But the scientists believe that the new bulb could reach efficiency levels of 40 per cent.
And it shows colours far more naturally than modern energy-efficient bulbs. Traditional incandescent bulbs have a ‘colour rendering index’ rating of 100, because they match the hue of objects seen in natural daylight. However even ‘warm’ finish LED or florescent bulbs can only manage an index rating of 80 and most are far less.
"The lighting potential of this technology is exciting." Prof Gang Chen, MIT
Researchers at MIT have shown that by surrounding the filament with a special crystal structure in the glass they can bounce back the energy which is usually lost in heat, while still allowing the light through.
They refer to the technique as ‘recycling light’ because the energy which would usually escape into the air is redirected back to the filament where it can create new light.
"It recycles the energy that would otherwise be wasted," said Professor Marin Soljacic.
An energy efficient light bulb
Usually traditional light bulbs are only about five per cent efficient, with 95 per cent of the energy being lost to the atmosphere. In comparison LED or florescent bulbs manage around 14 per cent efficiency. But the scientists believe that the new bulb could reach efficiency levels of 40 per cent.
And it shows colours far more naturally than modern energy-efficient bulbs. Traditional incandescent bulbs have a ‘colour rendering index’ rating of 100, because they match the hue of objects seen in natural daylight. However even ‘warm’ finish LED or florescent bulbs can only manage an index rating of 80 and most are far less.
Get the full story.........http://www.telegraph.co.uk/news/science/science-news/12093545/Return-of-incandescent-light-bulbs-as-MIT-makes-them-more-efficient-than-LEDs.html
