(Reuters) - British scientists have created what they believe is the world's smallest Christmas card, a seasonal greeting so tiny that over 200 million of them could fit into a standard postage stamp.
The card, created by the National Physical Laboratory (NPL), the U.K.'s national measurement standards laboratory, measures 15 x 20 micrometers. A micrometer is one millionth of a meter.
It is made from platinum-coated silicon nitride, and was illustrated using a focused ion beam. The card's cover features an etching of a snowman, above the words "seasons greetings," as well as a seasonal message inside.
One of the card's inventors, NPL's Dr David Cox, who created the card along with his colleague Dr Kin Mingard, said the technology used in its making had more practical uses.
"We are using the tools that created the card to accurately measure the thickness of extremely small features in materials, helping to unlock new battery and semiconductor technologies. It's a genuinely exciting development."
The NPL said that the previous smallest Christmas card measured 200 x 209 micrometers, making their effort over 100 times smaller.
(Writing by Mark Hanrahan in London, Editing by William Maclean)