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Prosecution Statement Must Be Clear and Unmistakable to Prevail over the Plain Language of the Claim

November 28, 2007

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Last Month at the Federal Circuit - December 2007

Judges: Dyk, Moore (author), Cote (District Judge sitting by designation, dissenting)

[Appealed from: S.D.N.Y., Judge Owen]

In Elbex Video, Ltd. v. Sensormatic Electronics Corp., No. 07-1097 (Fed. Cir. Nov. 28, 2007), the Federal Circuit held that the district court erred in its construction of the claim term “receiving means” of Elbex Video, Ltd.’s (“Elbex”) U.S. Patent No. 4,989,085 (“the ’085 patent”). In addition, the Court affirmed the district court’s grant of the SJ of noninfringement to Sensormatic Electronics Corporation (“Sensormatic”) with respect to two of its systems, but reversed the district court’s grant of SJ of noninfringement with respect to a third system and remanded.

The ’085 patent relates to closed circuit television (“CCTV”) systems. CCTV systems include a supervisory station and several remotecontrollable television cameras. According to the ’085 patent, an operator using a conventional system might inadvertently control the wrong camera, sometimes unknowingly. The ’085 patent seeks to solve this problem by employing a unique addressing scheme that includes using cameras to generate a first code signal unique to each camera in the system. That first code signal is sent, along with the video signal, to a receiving device located at the supervising station, where the first code signal is extracted by a decoder. After the receiving device receives a first code signal, that signal can be input into a “controlling means” that generates a second signal corresponding to the received first code signal and may transmit that second signal along with control commands to the camera.

Elbex sued Sensormatic, alleging that Sensormatic’s CCTV systems infringed claim 1 of the ’085 patent. Claim 1 requires, inter alia, “receiving means for receiving said video signals and said 1st code signals.” Slip op. at 3. The district court found that during prosecution, the inventor had limited the “receiving means” to a “monitor” that receives the video and first control signal. Id. at 4. Based on this construction, it granted SJ of noninfringement to Sensormatic because in Sensormatic’s systems, no data are ever sent from the camera to the monitor. In addition, the district court noted that Sensormatic’s CCTV systems did not satisfy the addressing limitations of claim 1. Elbex appealed.

On appeal, the Federal Circuit observed that because the “receiving means” limitation used “means for,” there was a presumption that the claim invoked 35 U.S.C. § 112, ¶ 6, and that the presumption had not been rebutted. The Court explained that its case law provides the appropriate framework for construing a claim limitation expressed in meansplus- function format, i.e., it must first determine the claimed function and then it must turn to the specification to determine which structures disclosed in the specification perform that function. Applying these principles, the Court noted that the function recited in the “receiving means” limitation is the reception of video signals and first code signals. Then, based on the specification, the Court found that the structure in the specification for performing this function included an input line, a low pass filter, an interface, and a television receiver or monitor and any equivalents.

The Court added that claim terms are entitled to a heavy presumption that they carry their ordinary and customary meaning to those skilled in the art in light of the claim term’s usage in the patent specification. However, noted the Court, when a patent applicant surrendered claim scope during prosecution before the PTO, the ordinary and customary meaning of a claim term may not apply. It explained that this doctrine of prosecution disclaimer does not apply where the alleged disavowal is ambiguous and that the disavowal must be both clear and unmistakable. The Court noted that the district court found that the inventor limited the “receiving means” to a “monitor” and that implicit in its determination was 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.

Disagreeing with the district court, the Federal Circuit concluded that the statement to the effect that the code signal was received by the monitor in the prosecution history did not amount to a clear and unmistakable surrender of claim scope. It noted that the statement was “unsupported by even a shred of evidence from the specification” and that read in isolation, the statement in the prosecution history could not be argued to be a disclaimer. Id. at 9. It observed that this statement, if taken literally, would result in an inoperable system and that Sensormatic’s own technical witness did not understand how such a system would operate. The Court stated that “[f]or 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.’” Id. at 10 (citation omitted). Accordingly, the Court concluded that this was not a case of prosecution disclaimer and that the receiving means was not limited to a monitor. Given its construction of the “receiving means” limitation, the Court found that the district court improperly granted SJ of noninfringement to Sensormatic.

The Federal Circuit then turned to the district court’s other rationale for SJ. It noted that the district court also concluded that SJ was appropriate because Sensormatic’s CCTV systems did not include a controller that generated a second code signal corresponding to a first code signal that is sent by the camera to the controller. The Federal Circuit agreed with this conclusion with respect to Sensormatic’s CCTV systems employing the RS-422 protocol and SensorNet protocols, and affirmed the district court’s grant of SJ with respect to those systems. However, with respect to Sensormatic’s CCTV systems using the Intellix IP protocols, the Court noted that it was unclear on the record before it whether address information within the data packages sent from a camera to the controller was used by the controller to address control signals to the camera. Because this fact was both material and disputed, the Court reversed the district court’s grant of SJ with respect to the Sensormatic systems using the Intellix IP protocol and remanded.

Judge Cote dissented. In a one paragraph opinion, she noted that when the prosecution history and the patent are considered together, the evidence is clear and ambiguous that Elbex’s reference to a “monitor” during prosecution was an unmistakable surrender of claim scope. She opined that Elbex made significant revisions to the claim to obtain the patent, and was now trying to recapture what it chose to abandon during prosecution.