Disclaimer in the Parent Application Affect Different Words in Continuation Applications Without Sufficiently Clear Warning to Examiner

Hakim v. Cannon Avent Group, PLC, [05-1398](February 23, 2007)[NEWMAN, Michel, Rader] The Federal Circuit affirmed summary judgment that U.S. Patent No. 6,321,931 is not infringed, and that U.S. Patent No. 6,357,620 is invalid.
SIGNIFICANCE: Different words in the same family of patents may have the same meaning, without a clear indication that different scope is intended. When pursuing broader claims after prosecuting a parent application, the applicant must provide a signal to the Patent Office when attempting to avoid affects of prosecution disclaimer.
BRIEF: After receiving a notice of allowance on a patent application on a no-spill drinking cup having a membrane with a slit, Hakim filed a continuation application using the term "opening" instead of "slit". This amendment was accompanied by a letter explaining that Hakim was broadening the claims. In construing the claims in the continuation patent, the district court held Hakim to his arguments in the parent application that the invention includes the presence of a slit in the flexible material because Hakim did not retract any of the arguments he made distinguishing the prior art in the abandoned parent application. While acknowledging that Hakim had the right to pursue broader claims in a continuation application, when rescinding a disclaimer made during prosecution, "the prosecution history must be sufficiently clear to inform the examiner that the previous disclaimer, and the prior art it was made to avoid, may need to be revisited." The Federal Circuit cited the public notice function of patent and its prosecution history requires that a patentee be held to what he declares during the prosecution of his patent. The trial court held that the '620 patent was invalid for anticipation. On appeal Hakim argued that it was improper to hold a claim invalid without first construing it. The Federal Circuit said that construction is not always necessary, where there is not dispute as to the meaning of a term that could affect the disputed issues of the litigation.