12.1'' mobile screen boasts 4K resolution
 

We've seen televisions and PC monitors with 4K resolutions. Now, a compact mobile display has joined the club. Japan Display has developed a 12.1" panel with a 3840x2160 resolution. The resulting pixel density works out to 365 PPI—the highest we've seen from a display suitable for notebooks and tablets.

http://techreport.com/news/25552/12-...-4k-resolution