Patent ID: 8040554

Claim:
A method of revealing hidden content associated with a printed substrate using a handheld display device having an image sensor, a transceiver and an opaque touch-sensitive screen, said method comprising the steps of: overlaying said device on part of said printed substrate; imaging an area of said substrate containing printed content but no hidden content printed thereon, and generating image data using the image sensor; determining interaction data using said image data, said interaction data identifying a page description corresponding to the printed substrate; sending the interaction data to a computer system, thereby causing the computer system to identify the page description and retrieve display data comprising first data corresponding to said printed content and second data corresponding to the hidden content; receiving the display data from the computer system; displaying, on said opaque touch-sensitive screen, display information based on said display data, said display information including first content matching with the printed content underlying said opaque screen and second content corresponding to the hidden content, such that the opaque screen has real-time virtual transparency through the screen to the printed content underlying said screen from a user's perspective to provide a virtual window to the printed content underlying said screen and wherein the opaque screen additionally reveals the hidden content in real-time as if it were printed on the underlying printed substrate.