	US 7,463,794 B2
	Optical imaging pen having an orthogonal accelerometer
Paul Lapstun, Balmain (Australia); Jacqueline Anne Lapstun, Balmain (Australia); and Kia Silverbrook, Balmain (Australia)
Assigned to Silverbrook Research Pty Ltd, Balmain, New South Wales (Australia)
Filed on May 04, 2008, as Appl. No. 12/114,805.
Application 12/114805 is a continuation of application No. 11/756624, filed on Jun. 01, 2007, granted, now 7,376,273.
Application 11/756624 is a continuation of application No. 10/943874, filed on Sep. 20, 2004, granted, now 7,388,985.
Application 10/943874 is a continuation of application No. 10/291589, filed on Nov. 12, 2002, granted, now 6,829,387.
Application 10/291589 is a continuation of application No. 09/575185, filed on May 23, 2000, granted, now 6,681,045.
Claims priority of application No. PQ0559 (AU), filed on May 25, 1999; and application No. PQ1313 (AU), filed on Jun. 30, 1999.
Prior Publication US 2008/0205762 A1, Aug. 28, 2008
Int. Cl. G06K 9/22 (2006.01)

U.S. Cl. 382—313 [382/187]

7 Claims

1. An optical imaging pen configured to capture and decode infrared (IR) position tags from a page, said pen comprising:

a force sensor photodiode configured to sense when a nib of the pen is in contact with the page;

an LED configured to project IR radiation onto a portion of the page when the nib is in contact therewith;

an image sensor configured to image the portion of the page when the nib is in contact therewith by receiving reflected IR radiation;

at least one orthogonal accelerometer configured to sense motion of the pen by sensing acceleration in x and y directions and integrating with respect to time to produce an instantaneous velocity; and

a controller arranged in signal communication with the accelerometer, photodiode and image sensor, said controller configured to control the photodiode and image sensor to capture, decode and encrypt the tags into digital ink data, and to include the instantaneous velocity of the pen into the digital ink data.