A pen system for recording a track of handwritten information. The system includes a handheld pen device having an image sensor, a processor and a first memory unit. The pen device generates digital ink by interacting with a coded surface and transmits the digital ink to a second memory unit located...http://www.google.com/patents/US7860349?utm_source=gb-gplus-sharePatent US7860349 - Pen system for recording handwritten information
