The US Patent Office has got a patent application from Sony Ericsson. The project describes a mobile phone with two detachable connected housings. The idea can be implemented in a clamshell, slider or a rotator-type phone. The phone consists of two parts: the one with the keypad and the battery (GPS-receiver and camera can go in there too) and the other with the display, some buttons and another battery. Both housings communicate with each other via Bluetooth.

The developers believe such design serves two opposite goals – while being compact, it provides a convenient hardware keypad. That is, you can use only the display housing and the rest of the phone put deep in your bag. Besides you can joint two parts with the main display on the inside or outside of phone, when closed.