A projector within a smartphone is nothing new. Years ago, Samsung did it in the Galaxy Beam. Lenovo, world's largest computer manufacturer, went a step further.
A new phone concept (Smart Cast) has been recently announced. Smart Cast will project its screen or keyboard (magnified, of course) onto a chosen surface, while built in sensors (probably infra-red) ensure the smartphone can be used through the projected image. When, for example, the keyboard is projected onto a wall, the user could type on it and the smartphone will recognise the input. If a piano keyboard was projected, one could "play" the piano on the projected image and corresponding sounds would be heard. Advantage? Size, more than anything. It is much easier to type on a larger keyboard or screen than on a small one...
The mini projector can, of course, be used for playback of videos or active use of games.
Lenovo corporation, fighting for as much of a smartphone market share as possible, said it would also be possible to browse the Smart Cast as a phone, independently from any contents being simultaneously projected. For now, no launch or shipping date has been announced.