(published on 10/22/2007)
Mary- In response to your question, I've modified the previous answer in this thread, which didn't seem quite accurate.
Mike W.
(published on 05/28/2013)
Did it gradually stop working? If so, the best guess is that you have the same problem that everyone else has. The atoms in the Indiglo device (maybe mostly in the form of Cu++ ions) get dragged out of place by the electric field. That gradually destroys the device.
Mike W.
(published on 01/20/2017)
(published on 10/22/2007)
John,
Indiglo watches take energy from the watch battery and give it to the atoms in the zinc sulfide-copper compound. This energy is then given off as light. After the atoms give off this light they can be exactly the same as they were before they got the energy from the battery. .
-matthew
People say that this Indiglo effect does wear out after long use, however. I bet what happens is a small amount of electromigration of atoms: under the influence of the electric field, atoms gradually get dragged out of position. As Matt said, it's not that the chemicals are getting used up like in a battery or a fuel tank. It's more that they just wear out, like the mechanical parts of an engine. In principle, they gradually wear out just by random thermal diffusion of the atoms, but it sounds like the electrically driven motion is more important under normal use.
Mike W.
(published on 10/22/2007)