Because Prosecution is a Negotiation, Prosecution Disclaimer Must Be Clear and Unambiguous

Elbex Video, Ltd. v. Sensormatic Electronics Corp., [2007-1097](November 28, 2007)[MOORE, Dyk, Cote] The Federal Circuit affirmed in part, reversed in part and remanded the district courts determination that Sensormatic’s accused closed circuit television (CCTV) systems do not infringe claim 1 of United States Patent No. 4,989,085.
SIGNIFICANCE: A prosecution disclaimer must be clear and unambiguous.
BRIEF: The district court found that the inventor limited the "receiving means" that receives the first code signal to a "monitor" that receives the first code signal. The Federal Circuit said that implicit in its determination is a finding that the inventor clearly and unmistakably surrendered any claim scope between the "receiving means" that receives first code signals as expressly recited in the claims, and a "monitor" that receives first code signals. The Federal Circuit disagreed. First, the Federal Circuit found that statement in the prosecution history is unsupported by even a shred of evidence from the specification. Second, when read in isolation, the statement in the prosecution history could be argued to be a disclaimer, but when the prosecution history as a whole is considered, the inventor’s response to the PTO is not as clear.
Third, reading the specification and remainder of the intrinsic record as a whole would lead those skilled in the art to the conclusion that the inventor’s statement was not a clear and unmistakable surrender of claim scope. The Federal Circuit said: "For a prosecution statement to prevail over the plain language of the claim, the statement must be clear and unmistakable such that the public should be entitled to rely on any 'definitive statements made during prosecution.'"
The Federal Circuit remanded this aspect of the case, but did affirm summary judgment of some of the systems on other grounds.