A NEW new lightbulb that lasts forever?

Extracts from
Everlasting light
An environmentally friendly bulb that may never need changing
From economist.com, June 19th 2007
The traditional incandescent lightbulb is a dud. It wastes electricity, radiating 95% of the energy it consumes as heat rather than light. Its life is also relatively short, culminating in a dull pop as its filament fractures.

Now a team of researchers has devised a lightbulb that is not only much more energy efficient. It also lasts, in effect, forever — that is, it is expected to last longer than the devices into which it is inserted.

The trick to a longer life, for lightbulbs at least, is to ensure that the lamp has no electrodes. [Electrodes wear out.]

[The new system] uses microwaves to transform electricity into light... The light is bright, and the process is energy efficient. Indeed, while traditional lightbulbs emit just 5% of their power as light, and fluorescent tubes about 15%, the Ceravision lamp has an efficiency greater than 50%.

Because the lamp has no filament, the scientists who developed it think it will last for thousands of hours of use—in other words, decades.

Another environmental advantage of the system is that it does not have to use mercury. The metal is highly toxic and is found in most of the bulbs used today, including the energy-saving bulb, fluorescent tubes and the high-pressure bulbs used in projectors.

Its developers reckon it should be cheap to make.

With lighting accounting for some 20% of electricity use worldwide, switching to a more efficient system could save not only energy but also on emissions of carbon.

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