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Genuine Issue of Material Fact as to Whether Prior Art Identified Symbols Based on Stroke Direction Renders Summary Judgment Inappropriate

June 08, 2006

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Last Month at the Federal Circuit - July 2006

Judges: Newman, Rader, Bryson (author)

In Xerox Corp. v. 3Com Corp., No. 04-1470 (Fed. Cir. June 8, 2006), the Federal Circuit reversed and remanded a grant of SJ of invalidity for anticipation and obviousness of Xerox Corporation’s (“Xerox”) U.S. Patent No. 5,596,656 (“the ’656 patent”), finding there to be a genuine issue of material fact as to whether the prior art identified shapes based on “strokedirection,” as required by the asserted claims. The Federal Circuit also concluded that dependent claims 9 and 11 of the ’656 patent were not insolubly ambiguous and thus reversed the district court’s grant of SJ holding those claims invalid for indefiniteness.

The ’656 patent discloses a system and method for “computerized interpretation of handwritten text.” The system employs an alphabet of “unistroke symbols” that correspond to alphanumeric characters, such as Arabic numerals and the letters of the English alphabet. Xerox brought suit against 3Com Corporation and six other defendants (collectively “3Com”). Xerox alleged that the ’656 patent was infringed by 3Com’s “Graffiti” system for handwriting recognition, which is used with 3Com’s PalmPilot handheld digital devices.

The district court granted SJ of invalidity, holding that the asserted claims were anticipated by a journal article written by D.J. Burr and a Japanese patent application by Tadahiro Nagayama. The district court also concluded that the term “sloppiness space” in asserted claims 9 and 11 was ambiguous and thus held those claims invalid for indefiniteness.

On appeal, Xerox argued that the ’656 patent was not anticipated by Burr because the invention of Burr failed to definitively recognize a symbol immediately upon pen lift, which was required by the asserted claims as construed by the Federal Circuit in a prior opinion. Xerox contended that symbol recognition in Burr is not complete until after “dictionary lookup” occurs. The Federal Circuit rejected this argument because Burr’s dictionary lookup is not a step necessary for recognition of a character to occur but simply serves as a means for later determining that a particular recognition may be erroneous. Likewise, the Court found that Nagayama’s “confirmation” step serves only as a means to correct errors in the recognition that has already occurred.

Next, Xerox contended that Burr did not disclose a system in which the symbols have “sufficient graphical separation to permit the computer to definitively recognize the symbol” upon pen lift, a requirement of the claims as construed by the Federal Circuit in its prior opinion. The Court rejected this argument because, having found that Burr did disclose definitive recognition of symbols upon pen lift, there must necessarily be sufficient graphical separation among those symbols to permit the computer to achieve definitive recognition.

Xerox similarly argued that Burr and Nagayama failed to disclose symbols that were accurately recognized on pen lift. The Federal Circuit rejected this argument, noting that nothing in the language of the claims or in the specification required a particular degree of accuracy for a system to qualify as producing “definitive recognition.” Moreover, in a journal article published prior to the litigation, an expert for the defendants reported that Burr’s invention achieved 90 percent character recognition accuracy without dictionary lookup.

Xerox further argued that Burr and Nagayama did not anticipate the ’656 patent claims, because neither reference disclosed a set of reference symbols that a user would emulate. The Court found, however, that the claims did not require such reference symbols and, regardless, such reference symbols were in fact disclosed by both Burr and Nagayama.

Xerox further contended that there was a material factual dispute between the parties as to whether Burr disclosed symbols that have “spatial independence,” as required by the claims. The Court dismissed this argument, finding that Burr did in fact disclose spatial independence because Burr’s system could distinguish and recognize symbols without reference to where a previous symbol was written.

Xerox also argued that Burr failed to disclose the claim limitation of “some of said unistroke symbols being linear.” In particular, Xerox contended that the district court erred in concluding that Burr’s T-shaped symbol was linear. The Court again dismissed this argument, noting that one dictionary definition of the term “linear” is “of or pertaining to a line or lines.” Moreover, the Court noted, each time the term “linear” is used in the claims, it is used in contrast to the term “arcuate.” Thus, the Court held, the term “linear” was used in the patent to denote consisting of a straight line or lines, as opposed to consisting of curves, and thus Burr’s T-shaped symbol would be considered linear.

Xerox also contended that Burr did not rely on stroke direction to identify symbols, as required by the claims. On this issue, the Federal Circuit agreed that there were genuine issues of material fact. The Court concluded that a close reading of the Burr article suggested that although Burr’s invention undoubtedly captures stroke direction data, it may not use that data to distinguish one symbol from another. Similarly, the Court found that although Nagayama appears to disclose the capture of directional data and subsequent shape matching, it was not clear that Nagayama distinguishes symbols based on both geometric shape and stroke direction. Consequently, the Court concluded that a genuine issue of material fact remained as to whether the Burr and Nagayama references disclose the various “stroke direction” limitations of the asserted claims of the ’656 patent. The Court therefore vacated the district court’s grant of SJ of invalidity for anticipation and obviousness, and remanded the case to the district court for further proceedings with particular focus on whether the Burr or Nagayama references disclose the use of stroke direction in distinguishing symbols.

The Federal Circuit then turned to the issue of indefiniteness of dependent claims 9 and 11, which required that the symbols must be “well separated from each other in sloppiness space.” The district court had concluded that the claim term “sloppiness space” was ambiguous and not adequately defined in the patent. The Federal Circuit reversed, finding that the specification explicitly defines symbols that are “well separated from each other in sloppiness space” as those distinguished by substantial angular offset (e.g., at least 45 degrees and preferably 90 degrees) or directional distinction (opposing directions). The Court noted that the specification also contrasts symbols that are well separated from each other in sloppiness space from the characters of the ordinary Roman alphabet, which are not reliably distinguishable from each other in the face of rapid or otherwise sloppy writing. The Court explained that “[w]hile those descriptions are not rigorously precise, they provide adequate guidance as to the types of symbols that are ‘well separated from each other in sloppiness space,’ particularly in light of the difficulty of articulating a more exact standard for the concept.” Slip op. at 23. Thus, the Court held that claims 9 and 11 were not insolubly ambiguous and, therefore, not invalid for indefiniteness.