The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 09, 2004
Filed:
May. 10, 2000
Gregory Fraser Russell, Yorktown Heights, NY (US);
Barton Allen Smith, Campbell, CA (US);
Thomas Guthrie Zimmerman, Cupertino, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A digital pen that has a writing tip includes an ultrasonic (US) transducer on a pen body that generates frames of US pulses toward a receiver base in response to an infrared (IR) synchronizing signal from the base. The first pulse of a frame is adjusted by a modulo of the US period &tgr; when the time of arrival (TOA) of the first pulse varies from an expected TOA by more than one-half &tgr;. The TOAs of successive i pulses in the frame, which are one wavelength apart from each other, are adjusted forward in time by subtracting from each pulse TOA (i−1)&tgr;, and then several of the adjusted pulse TOAs in a single frame are averaged together to determine a frame TOA. The frame TOAs from plural receivers on the base are then triangulated to determine a pen position for that frame, with the pen positions being input to a handwriting recognition module.