Everlasting light

Scientists have devised a light bulb that lasts forever — that is, it is expected to last longer than the devices into which it is inserted.

Despite its use to symbolize a bright idea, the traditional incandescent light bulb 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 light bulb that is not only much more energy efficient. While traditional light bulbs emit just 5% of their power as light and fluorescent tubes about 15%, the Ceravision lamp has 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. Moreover the light it generates comes from what is almost a single point, which means that the bulbs can be used in projectors and televisions. Because of this, the light is much more directional and the lamp could thus prove more efficient than bulbs that scatter light in all directions. Its long life would make the new light ideal for places where the architecture makes changing light bulbs a complicated and expensive job. Its small size makes it comparable to light-emitting diodes but the new lamp generates much brighter light than do those semiconductor devices.

The Economist