The world's smallest radio frequency identification tags have been unveiled by Japanese electronics firm Hitachi. The minute devices measure just 0.05mm by 0.05mm (0.002x0.002in) and to the naked eye look like spots of powder.

Here the tiny tags can be seen next to a human hair

They are thin enough to be embedded in a sheet of paper, Hitachi spokesman Masayuki Takeuchi says. Hitachi says it wants to study the tags' possible uses, but it does not yet have any plans to put its latest creation into commercial production.