Just think of the logistics. Using a multi milion dollar laser to make a lowly lightbulb more efficient. Does this thing work on only one bulb at a time or could it do a whole batch at once? 'seems like a really expensive way to do it. It's still really cool though.
I know that it would be done in a factory making these things. I was just curious about the logistics of a factory doing this. Obviously, if you had to do it one bulb at a time, a factory could not use this technique.
Greg I wondered about that too. The life of a tungsten filament [at design temperature 3100º-5400ºF] is a factor of surface damage to the filament, at a heat approaching the fusion point of tungsten [6192ºF] and by cyling on and off. Minute cracks and 'hot spots' appear, which slowly enlarge and lead to failure, buffered by the choice of inert gas fill, argon, nitrogen, halogens. If this 'laser surface' treatment is degraded by the heat in less than the normal bulb life, the whole idea will be useless.
Ian, the pulse is so short that it wouldn't really slow down the line if they shot each bulb one at a time as they go by. I assume they would cost a little more but if I was in the incandescent bulb business I would be willing to do a lot to save my business.
It seems that it takes more than one shot with the laser. The article stated that the treated "spot" was brighter. There is no report on the size of the spot, could be anywhere from 1/3 of the filiment (meeting the largest size I could call a spot) to the size of the pointed end on a pin or smaller depending on what they were using to observe the spot.
Very good point. Lasers, at the power levels they are working with, have beam diameters of just a few microns. So, I would imagine, the affected area of the filament would be very small indeed.
