Internet Library of Law
and Court Decisions

Xerox Corp. v 3 Com Corp., et al.

District Court holds invalid Xerox's patent for a computer system that recognizes handwritten symbols known as "Unistrokes" because it was rendered obvious by prior art.  The Court accordingly granted defendant 3Com Corp.'s motion for summary judgment, dismissing claims that defendant's Palm Pilot, which uses a computer based system known as "Graffiti" to recognize unistroke symbols, infringes Xerox's patent.

This is the fifth major court decision in this long running litigation.  On June 6, 2000, the District Court held that defendants' Palm Pilot did not infringe Xerox's patent.  This decision was reversed by Federal Circuit Court of Appeals in a decision dated October 5, 2001, which went on to affirm the District Court's interpretation of the patent's claims.  Thereafter, in a Decision dated December 20, 2001, the District Court upheld the validity of Xerox's patent, and found that defendants had infringed it.  Again the Court of Appeals reversed, this time finding the District Court had failed to consider whether the patent was valid in light of certain cited prior art references.  In its February 20, 2003 decision, the Appellate Court did affirm the District Court's determination that, if the patent was in fact valid, defendants had infringed it.

In its May 21, 2004 decision, the District Court once again addressed the validity of Xerox's '656 Patent.  A patent will be held invalid if the invention it discloses is anticipated 35 U.S.C. §102 or made obvious by prior art 35 U.S.C. § 103.  A claim is obvious if the patented invention would have been obvious to a person skilled in the art at the time the invention is disclosed.  The issuance by the US PTO of a patent, or its affirmation of the patent's validity, is not dispositive on this question.

In determining whether a patent claim is anticipated or obvious, the court must first construe the claims of the patent at issue, and then compare the claims as construed to existing prior art.  As stated above, here, the claims of Xerox's '656 patent had previously been construed both by the District Court and the Court of Appeals in prior decisions.  In those decisions, the claims were held to "contain two key elements: 'graphical separation' and 'spatial independence.'… '[G]raphical separation' [was construed by the Court of Appeals] to describe unistroke symbols that have 'sufficient graphical separation' for a computer to 'definitely recognize a symbol immediately upon delimitation or pen lift.'  … The term 'spatial independence' has been construed by the Court of Appeals to require that 'the accused device be able to distinguish between and recognize symbols without reference to where a previous symbol was written on the written surface."

The Court held that Xerox's '656 was anticipated and rendered obvious by two pieces of 'prior art' and hence was invalid.

The first of these prior art references was contained in a 1983 journal article authored by D.J. Burr, then working for Bell Labs.  "The article, entitled 'Designing a Handwriting Reader,' proposes the creation of a computer based handwriting recognition device in which a user inputs data using only single stroke curves."

The second piece of prior art relied upon by the Court in reaching its decision was a patent application published by the Japanese Patent Office in February 25, 1985.  Authored by Tadahico Nagayma, the application was titled "Control Method Using Real-Time Recognition of Handwritten Character Patterns" and "discloses a method for using handwriting recognition to enter commands into a computer.  The reference discloses the use of single-stroke characters or figures that can be written anywhere on a digitized surface, which, upon pen lift, are recognized by the device.  The recognized figures correspond to commands, functions, menu items, or other items."

The Court held that "both the Burr and Nagayama references teach the use of single-stroke symbols that are definitely recognized upon pen lift … [and] teach devices which allow symbols to be written anywhere on the recognition surface, without respect to where the previous symbol was written."

Accordingly, said the Court, "Because I find that the Burr and Nagayama references anticipate and render obvious the claims of the '656 patent, I find that the '656 patent is invalid in light of those prior art references."