Scientists in Britain have developed a super-efficient light bulb that works without filament -- thus making it likely to last longer than the machine that contains it:
Scientists working for Ceravision, a company based in Milton Keynes, in Britain, have designed a lamp that eliminates the need for electrodes. Their device uses microwaves to transform electricity into light. It consists of a relatively small lump of aluminium oxide into which a hole has been bored. When the aluminium oxide is bombarded with microwaves generated from the same sort of device that powers a microwave oven, it generates a concentrated electric field in the void.
If a cylindrical capsule containing a suitable gas is inserted into the hole, the atoms of the gas become ionised. As electrons accelerate in the electric field, they gain energy that they pass on to the atoms and molecules of the gas as they collide with them, creating a glowing plasma. 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. 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 lightbulbs 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.
See, now that's thinking outside the box. Someone put a fork in their microwave and said to themselves, "You know that did fry my microwave, but it also produced a lot of light doing it. Perhaps I could have one without the other..."
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Their website says:
Varying the chemistry of the metal halide salt mix allows the spectral emission to be tuned to the needs of specific applications. This includes various colour temperature variants of "white light", "UV light" or exclusively "IR light".
Very cool. Or hot, whatever.
The standard flourescent and compact flourescent bulbs have no filament.
LEDs have no filament.
Microwave generation is not trivial and requires parts that are far more prone to failure than LEDs, and no less prone to failure than good quality flourescent light ballasts.
This is interesting as pure science, but it's not particularly interesting as a means of commercial or residential lighting. LEDs are in no danger of being dethroned as the longest-lasting and most efficient form of mass-market lamp.
Well, I certainly hope someone comes up with a practical, efficient replacement for flourescent lights. I hate the stupid tube type (what kind of brain-damanged idiot came up with the design of the contacts?) and the much-touted CF, which are supposed to last for next-to-forever, seem to burn out much quicker than that, I have found. So, bring on the LEDs or the plasma bulbs or whatever it's going to be.
If this works, imagine what it will do to the future of "how many [category of person] does it take to change a lightbulb" jokes.
Question: How many people does it take to change a plasma lightbulb?
Answer: How many do you have after five generations?
This is a amazing. I'm glad it's a green festival. Since green businesses are popping up left and right, I love that The Social Venture Network is holding a contest to reward business leaders
of socially responsible companies! If you know a CEO or high-level
person in such a company, please send this link to them:
www.svn.org/imaginewhatsnext .