a new incandescent light bulb ?

If you can wade through all the proclamations of #awesome meetings interesting information sometimes finds its way through twitter. One interesting scrap about incandescent light bulbs came along a while ago.

Yes, I did say incandescent light bulbs; and yes they have been banned in several jurisdictions, including Canada.  A tweet linked to a BBC story about the work at MIT.  If you are so inclined the original scientific paper is published here in Nature Nanotechnology.  In short, this work claims a comparable, if not higher energy efficiency than that of LEDs, the current efficiency leader.

As everyone knows traditional incandescent light bulbs run hot.  In these bulbs a tungsten filament is heated to approximately 3000 deg.C, where it emits both infrared and visible light.  Something well over 90% of the input energy is emitted as infrared radiation i.e. heat.  With so much energy going to heat instead of light such bulbs are a rather inefficient source of light, thus the ban.  On the plus side  incandescent bulbs are simple.  There are no control electronics.  There are no discretes, ICs or circuit boards.  The bulb simply has a set of contacts to supply electricity to the tungsten filament.

What is this research doing?  How does it work?  A “cold-sided nano-photonic interference system” i.e. stack of very thin dielectric layers covers the tungsten filament.  In one example the 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.