a new incandescent light bulb ?
After wading through all the proclamations of #awesome meetings, twitter does sometime point to interesting bits of information. One of these bits highlighted research in incandescent light bulbs.
Yes, I said incandescent light bulbs and yes they have been banned in several jurisdictions, including Canada. The tweet linked to a BBC story about work at MIT. If you are so inclined the original scientific paper is published here in Nature Nanotechnology. In short, incandescent lightning with a comparable, if not higher energy efficiency than that of LEDs, the current efficiency leader, is being developed.
background
Traditional incandescent light bulbs are quite simple and they run hot. There are no “extra” electronics. There are no ICs. There are no circuit boards. The bulb simply has a set of contacts to supply electricity to a tungsten filament. When switched “on” the electrical current heats the filament to approximately 3000 deg.C. At this temperature it emits both infrared and visible light. Over 90% of the input energy is emitted as infrared radiation i.e. heat i.e. only 10% generates light. With so much energy going to heat instead of light such bulbs are a rather inefficient source of light, thus the ban.
a new filament
The current research developed a so-called “cold-sided nano-photonic interference system”. Say again. The new filament still has a tungsten core, but a stack of very thin dielectric i.e. non-conducing layers is formed on the outer surface of the tungsten filament. In one example this stack contains several hundred layers of various oxides. In the end, the stack allows visible light to pass through, but infrared light is reflected back into the filament. This reflected infrared light contributes to the heating of the filament, reducing energy consumption.
At the moment this development seems to be in early stages. There will certainly be more work at the research stage and then there will be engineering and process development before any commercialization. For sure there will be plenty of questions that will need to be answered. Is the process scalable? Can the efficiency be further improved? What are the best material systems for the stack?
What about Intellectual Property? The Nature article indicates that improving the efficiency of incandescent bulbs by recycling infrared radiation is known. It then indicates how the current work is novel. Thus, even with the very broadest concept known there is very likely patentable subject matter around this concept and work. One can envision patents around the stack structure, stack materials, methods of fabrication, methods of use. The list goes on and on. If this concept can advance to a commercial scale it may well present an interesting competitor to current lighting paradigms.
Stay tuned.