What is Projectable Interface

Mobile devices have so far been personal tools. With their evolution of increased functionality, however, these devices have begun to be used in a shared fashion by multiple people. This chapter discusses techniques allowing multiple people to share mobile devices by projecting their displays and conducting intuitive manipulations on them. The chapter first shows overviews of systems and technologies related to location-aware projection and several interaction techniques. Then, a system called Hotaru that implements intuitive manipulation techniques on projected displays of multiple mobile devices is described. Hotaru allows a user to annotate or rotate a picture or a document on a projected display by using his finger and intuitively to transfer a file between multiple devices by overlapping their projected displays. User studies of Hotaru indicated that the proposed manipulation techniques could support multiple people in a single location in conducting their tasks. Research issues on projected displays of mobile devices are raised.