Get a second chance to the good old, unfortunately extremely inefficient bulb maybe? American scientists succeeded thanks to nanotechnology, to redirect the strong thermal radiation of the light bulb and dramatically increase its luminosity. Bulbs fans may hope for a comeback.
The resistance of the consumer was great, as the European Commission 2008 announced the progressive manufacturing and sales ban of the bulb. Alternative light sources such as halogen lamps or LEDs have been improved since then always continue, but they don’t get to the warm glow of the light bulb of the environment in particularly full color quality seems.
However, the fans of the bulb to the fact not came around that this is extremely ineffective. Approximately 95% of their energy radiates it as heat, rather than visible light. An American team of researchers has now apparently found a way to drastically reduce this heat loss, and to make the light bulb in a new light.
The heat energy is reflected and recycled
The physicist from Massachusetts of technology (MIT) have presented their potentially groundbreaking invention in the journal Nature Nanotechnology Institute in Cambridge and at Purdue University in West Lafayette. Nano-technology is the key to the new method, with which the bulb could experience a revival. The traditional glow-wire, which is heated up to 2700 ° c, remains in principle as before and was changed only in its form. But now the heat energy that is emitted in the form of infrared radiation and mostly lost, from there is led back and again harnessed. The researchers speak of a ‘recycling’.
For this they have surrounded the glow with a nano-structure, but lets through visible light, infrared radiation. Up to 90% of this radiation are reflected, absorbed by the glow wire and broadcast as visible light. The nano-structure consists of Photonic crystals in many layers that allow visible light, but reflect infrared radiation at different angles. In addition, to improve the recovery of heat radiation, the researchers instead of a filament used a flat sheet of tungsten.
Light output is two to three times as large as before
In the first prototype, the new bulb reached a light yield of 6.6%. The light yield represents the light output of a lamp in relation to the recorded performance. The greater the number of, the luminous flux usable for the eye is greater. These luminous efficacy is a light bulb of the old type 2-3%, with energy saving lamps between 7% and 15% and LEDs between 5% and 15%. The nanostructure method would be so already now comparable with modern bulbs, the scientists assume that the efficiency of the new bulb can be considerably increased by the luminous efficacy.
With significantly higher efficiency of the light bulb whose warm glow go not lost yet, the researchers report. It should also be the bulbs quite inexpensive to produce, because the materials that are abundant and cheap. The technology not only on light bulbs would apply but for example also in the Thermophotovoltaics is combined in the electricity and heat generation.
Smallest incandescent lamp in the world
Researchers from New York have also nanotechnology experimented with: you have heated graph by electricity and hoped that that begins to glow only one atomic layer thick lattice structure.
And there was light. Now, the simple design is known as the smallest incandescent lamp in the world.