An Incandescent Lightbulb Comeback?

A team of researchers at MIT have reinvented the traditional incandescent lightbulb by incorporating a special crystal structure filter around the filament of the bulb that allows visible light waves to pass through while ‘recycling’ or ‘bouncing back’ the energy that would normally be lost in a conventional bulb. The researchers claim this development could significantly improve the efficiency of the traditional incandescent light bulb, and perhaps even lead to its reintroduction to the market.

The traditional incandescent lightbulb has been phased out of the lighting industry in recent years, being banned in the EU and Canada and sharply restricted in the United States in favour of more energy efficient florescent and LED bulbs. A traditional bulb for instance demonstrates only around 5% efficiency, losing 95% of its energy to its surroundings. By contrast, florescent or LED bulbs demonstrate around 14% energy.

The appeal of and nostalgia for the warm glow of a traditional bulb has remained though, particularly with many complaining that more energy efficient LEDs have a time delay and their white light results in a clinical, unnatural feel.

Thanks to advances in nanotechnology however, MIT researchers have shown that a specially developed filter of photonic crystals surrounding the traditional filament captures the infrared radiation that would normally escape as heat. Rather than escaping, this radiation ‘bounces back to the filament and continues a cycle of reflecting, reabsorbing and re-emitting in the form of visible light. With this new technique, scientists anticipate that the reinvented traditional bulb could achieve an efficiency level of 40%. As an added benefit, the light that is given off is far warmer and more natural than that emitted by current energy efficient bulbs. Traditional bulbs have a ‘colour rendering index’ rating of 100, which is comparable to natural daylight. By contrast, LED and florescent bulbs manage a maximum rating of 80, which the majority being far less.

And it gets better. There is currently considerable concern from advocates about the dangerous chemicals contained within modern efficient bulbs. And furthermore, researchers have indicated that the blue light emitted by then could prevent people getting proper sleep at night. So in this sense, a return to the traditional bulb could even be good for your health!

These new findings are published in the journal Nature Nanotechnology.

Source via MIT news.