The Compose music tablet is a design concept, by Ouyang Xi, He Binbin, Zeng Li & Li Bo, intended to provide a mobile composition solution.
The pen acts as a mic that you sing into. When docked into the digital paper tablet, your vocal harmonies are automatically transcribed from the recording in the pen into a score.
For old schoolers, you can write directly on the display. It also contains sound libraries for an entire orchestra – so once your composition is finished, you can play it back.
I saw this at Yanko Design, which, unfortunately, does not link to the designers’ page or offer much in the way of information. If you’ve got any additional info on this, let me know in the comments.