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District Court Fails to Properly Apply Its Own Claim Constructions

00-1464
October 05, 2001

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Last Month at the Federal Circuit - November 2001

Judges: Mayer (author), Newman, and Clevenger (concurring)

In Xerox Corp. v. 3Com Corp., No. 00-1464 (Fed. Cir. Oct. 5, 2001), the Federal Circuit affirmed-in-part, reversed-in-part, and remanded a decision granting Defendants, 3Com Corporation, U.S. Robotics Corporation, U.S. Robotics Access Corporation, and Palm Computing, Inc. (collectively “3Com”) SJ of noninfringement of U.S. Patent No. 5,596,656 (“the ‘656 patent”) owned by Xerox Corporation (“Xerox”). Specifically, the Federal Circuit affirmed the district court’s claim constructions, but found that the district court had failed to properly apply its constructions to the accused device.

The ‘656 patent relates to a system for computer recognition of handwritten text using singlestroke symbols, called “unistrokes,” entered by a stylus or pen on a pressure-sensitive surface. The system employs a so-called delimiting operation by which successive unistroke symbols can be distinguished from each other without reference to and independently of “the spatial relationship” of the unistroke symbols with respect to each other. This delimiting operation can be accomplished by lifting the stylus or pen from the surface on which the unistroke symbols are written.

Xerox had brought suit against 3Com claiming that 3Com’s “PalmPilot” line of hand-held computers used the claimed unistrokes technology in its “Graffiti” software.

Both Xerox and 3Com had moved for SJ on the issue of infringement. The district court had granted 3Com SJ of noninfringement and denied Xerox’s motion. As part of its decision, the district court had construed the asserted claims and held: (1) the definition of “unistrokes” itself does not require an entire alphabet of symbols; (2) the term “unistroke symbols” requires sufficient graphical separation so that the computer can definitively recognize a symbol immediately upon delimitation or pen lift; and (3) “spatial independence” requires the accused device to be capable of properly distinguishing and recognizing symbols without reference to where a previous symbol was written on the writing surface.

Applying the construed claims to the accused device, the district court had found no infringement for three reasons: (1) some of the symbols used in Graffiti are not sufficiently “graphically separated” from each other to be “unistroke symbols”; (2) Graffiti does not employ “spatial independence”; and (3) Graffiti does not allow for “definitive recognition” of some symbols immediately upon pen lift by the user.

The Federal Circuit affirmed the district court’s claim construction, but reversed the district court’s judgment that those properly construed claims did not cover the accused device. First, the Federal Circuit found that the district court had erred in declaring that the Graffiti symbols are not sufficiently ”graphically separated” from each other to be “unistroke symbols.” This error occurred because the district court had looked only to the geometric overlap between symbols and had ignored the direction the pen must travel to create the symbol, an integral aspect of the claims of the ‘656 patent—namely, that each unistroke symbol has “geometric shape and direction.” According to the Federal Circuit, had the district court properly applied its own claim construction, it could not have said that Graffiti symbols are not graphically separated from each other sufficiently to be unistroke symbols.

Second, the Federal Circuit found that the district court had erred in declaring that Graffiti does not allow for “definitive recognition” of symbols immediately upon pen lift by the user. According to the Federal Circuit, the district court had failed to consider the difference between definitive recognition of a symbol, which is claimed, and definitive recognition of a character, which is not claimed. Thus, with respect to the two strokes required to form accented vowels in Graffiti (the example relied on by the district court), the first stroke is definitively recognized as the symbol for the vowel and the second stroke is definitively recognized as the symbol for the accent, which is all the claims require. Consequently, each symbol in a multistroke, multisymbol character in Graffiti is definitively recognized when the pen is lifted, even though the characters that are displayed may be altered by subsequent strokes.

The third error found by the Federal Circuit concerned the district court’s conclusion that Graffiti does not employ “spatial independence.” As noted above, the district court had correctly stated that spatial independence required the invention to be capable of properly distinguishing and recognizing symbols without reference to where a previous symbol was written on the writing surface. Nevertheless, in applying the claims, the district court had concluded that there was no infringement because Graffiti requires the computer to consider the placement of the stroke on the writing surface when performing recognition of a symbol after the pen is lifted. This was error because the location of the current symbol on the writing surface is not the issue in determining whether the “spatial independence” limitation was met. Rather, that limitation would be met if a computer recognizes the current symbol without reference to where a previous symbol was written.

In his concurring opinion, Judge Clevenger emphasized that for infringement to be found on remand, every symbol made by a single stroke that is used by the Defendants must be a “unistroke symbol,” as defined by the Court.

[Don Dunner, Tom Jenkins, and Bruce Bower of our firm successfully represented Xerox on this appeal.]