A US court has ruled that Xerox's patent for its Unistrokes single-stroke handwriting recognition software is invalid and, as a result, dismissed its suit against PalmOne.
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Xerox had contended that Palm's handwriting recognition technology for PDAs violated one of its patents, which covers Unistrokes symbols. But for the second time, judge Michael Telesca terminated the patent infringement lawsuit.
Unistrokes was developed by Xerox in the early 1990s as a technology for allowing users to input information to a computer by printing in a special shorthand. Its patent for Unistrokes was granted in January 1997 and the following April, Xerox sued US Robotics, charging that the Graffiti software used in Palm handheld organisers infringed upon its patent.
As the lawsuit made its way thorough the courts, US Robotics was acquired by 3Com, which then spun off Palm in March 2000. Palm in turn spun off PalmSource, the maker of the Palm OS platform, acquired Handspring and renamed the new configuration PalmOne in October 2003. PalmOne retained liability for the Xerox action.
Telesca had first dismissed the lawsuit in June 2000, when he ruled that Palm's Graffiti did not use the same recognition patterns as Xerox's technology. The lawsuit was revived in October 2001 after an appeal ruled that Telesca had misunderstood how and where symbols must be writtento be recognised by the handheld device.
That December, based on the guidelines put forth by the Court of Appeals, Telesca found in Xerox's favour, stating that its patent was "valid and enforceable" and clearing the way for Xerox to seek damages.
But the appeals and requests for summary judgements continued, and Telesca was required by the Court of Appeals to conduct a full analysis regarding the validity of the patent.
In the latest ruling, Telesca agreed with PalmOne's contention that the Unistrokes handwriting-recognition software should not have been granted a patent as the technology in question already existed when the patent was applied for, a common antipatent argument known as "prior art".
In total, PalmOne said there were three cases of prior art that, like Unistrokes, "disclosed spatially independent, graphically separated single-stroke symbols that are recognised immediately upon delimitation", according to the ruling.
Telesca found that a 1983 journal article, Designing a Handwriting Reader, by DJ Burr, who at the time of authorship worked for Bell Laboratories, and a patent application granted by the Japanese Patent Office in 1984 to Tadahiro Nagayama for the “Control Method Using Real-time Recognition of Handwritten Character Patterns” were both cases of prior art.
"The prior art references anticipate and render obvious the claim," the judge wrote in his ruling.
PalmOne's third prior art reference, Microsoft's PenWindows for pen-based computing systems, which was shipped to customers in 1992, was not ruled on by the judge.
Representatives for Xerox and PalmOne could not be reached for comment, though in a statement PalmOne said it was pleased with the ruling.
Laura Rohde writes for IDG News Service