For the wearable devices that have embedded projectors, Samsung filed a patent application. In the pre defined spaces, these projectors display a UI, and can take inputs from the users based on direct interaction in those pre-defined spaces.

A projector embedded in a smartwatch is one set of uses for a device.

Mapping out the user's hand shape, the projector projects a screen that will fit within the boundaries of that hand. However, the projection does not extend to back of the hand, but can be projected downwards right along the arm, or upwards into the fingers.

For a large screen UI, the same smartwatch can even be used to project on wall.

Ranging from simple interfaces, for dialing and messaging, to showing related information related to navigational searches, the usage scenarios exist.

The projected area can also have a number pad, a keyboard, or show extended menu functions for one of the applications being used. The users in the interface screen projected, can even draw or write, on the back of the hand or anywhere else.

Not just the smartwatch, the patent also covers use of the interactive projector on a VR headset, or a headset like device. This could mean using the embedded projecter, as an input device in augumented reality spaces.

One important aspect of the patent application is the tracking resolution for the fingers and understanding gestures.
 
The wearable devices even include an omni directional lense, to capture images of the projected UI's operating area. Several other wearable things like ring, headband and belt also includes patent application.

By Phani Ch