Sunday, October 4, 2009

Properties of black bodies and white bodies

Duh!

Black bodies are perfect absorbers of radiation and perfect emitters of radiation;
white bodies are perfect reflectors of radiation and perfect retainers of radiation.

The filament in a light bulb is shiny. If you treat it with a laser to make it black, not only does it become a better absorber, but it becomes a better emitter!


This still does not bring it anywhere near to LED efficiency, however.

I wonder if the process could be used to improve light emission from LEDs or heat dissipation from the bulb stem. The stems do get quite hot. It is puzzling to me why the stems of LED light bulbs are silver. Shouldn't they be black or at least a dark color? Perhaps it is maximally transparent in the infrared already. That would seem to be obviously desirable.

Perhaps the aluminum used in the stem could be made black, or another metal could be used that could be made black.
http://www.rochester.edu/news/show.php?id=3106

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