A technology to put the mobile phone on the palm of your hand is being developed by researchers from the University of Tokyo.

Ishikawa said that the technique can detect movement of a 3-D object every two milliseconds, in other words, the high-speed vision allows the program to track moving objects, so users would be free to walk with the phone image in palm, without the display ever shifting.
Also the ultrasonic wave emitters are beamed by the computer system, so that user feels the keyboard pressing against their skin, without anything being in their hand.
Ishikawa said that the sensation is the equivalent to a 3-gram or 0.1- ounce object.
Source-ANI