Lenovo has unveiled the Smart Cast, a phone with a built-in laser projector that can be used to display a virtual keyboard or display.

The interactive display can replicate the phone’s touch screen, a full-size computer keyboard or even piano keys.

The laser projector can also be used to beam images and videos onto walls.

The Smart Cast phone was unveiled at Lenovo’s Tech World conference in Beijing, where the Chinese electronics giant also unveiled a new type of smart watch, called Magic View.

The laser projector measures just 34mm by 26mm by 5mm and, said Lenovo, does not need focusing to project sharp images onto walls or other flat surfaces.

A video showing the Smart Cast in action shows how twisting the mounting for the device’s lens turns it from a standard wall projector into “surface mode” that beams the display on to a table top.

A kickstand mounted on the back of the phone keeps the device upright while the virtual keyboard is in use.

At the Tech World conference, Chinese concert pianist Lang Lang used the virtual keyboard to play a version of The Entertainer.

Tech World also saw Lenovo show off a smartwatch, called Magic View, that has two screens.

Magic View smartwatch has a standard “public” screen viewable by anyone and a second “private” projected screen only visible when the watch is held close to the face and at a specific angle.