Patent ID: 8035850

Claim:
A method of retrieving display data for a handheld display device, said method comprising the steps, in a server, of: receiving interaction data from the handheld display device, said interaction data being generated by the device using image data acquired by imaging an area of a printed substrate containing printed content; identifying a page description corresponding to the interaction data; retrieving display data using the identified page description, said display data corresponding to at least some of the printed content imaged by the device; and sending the display data to the handheld display device, thereby causing the device to display display-information based on said display data so as to enable user interaction with the display-information via an opaque touch-sensitive display screen of the device, wherein, from a user's perspective, the opaque screen has real-time virtual transparency through the opaque screen to the printed content underlying said screen to provide a virtual window to the printed content underlying said screen.