Prosecution Disclaimer Applies Even if the Disclaimer Results in a Negative Claim Limitation

RFID Tracker, Ltd. V. Wal-Mart Stores, Inc. (Fed. Cir. Aug. 18, 2009) (nonprecedential)

In this case, the district court (Eastern District of Texas) entered final judgment of noninfringement after claim construction and a stipulation by the plaintiff that the defendants did not infringe under the entered claim construction. The Federal Circuit, in a per curiam opinion, affirmed.

The disputed claims relate to an inventory control system that includes radio frequency identification ("RFID") tags attached to inventory items, an interrogator/reader, and a computer. The district court construed the claim term "interrogator/reader" as "an interrogator/reader includes a field generator and a receiver, but not a transmitter." As none of the parties disputed that the accused devices contained a transmitter, the district court entered final judgment of noninfringement.

One disputed claim recited, in part, an "interrogator/reader" that included a "field generator" and a "receiver." RFID argued that the claim used "the open-ended term 'including,' which, similar to 'comprising,' raises a presumption that the 'interrogator/reader' is not limited to a 'field generator' and a 'receiver' and may include a transmitter." The Federal Circuit found that while "the specification does not rebut RFID's alleged presumption that the interrogator/reader can include a transmitter ... [during prosecution] [t]he applicant differentiated its claims from the prior art on the ground that the claimed interrogator/reader was simple, unlike the complex readers of the prior art that contained and used a transmitter." Father, "[i]n light of these statements during prosecution, RFID cannot now contend that the claimed interrogator/reader is anything more than 'simply a receiver and a field generator in its simplest form.'"

While the district court's construction included a negative limitation (the phrase "but not a transmitter"), "[i]f the applicant unequivocally disavows claim scope, the doctrine of prosecution disclaimer applies even if the disclaimer results in a negative claim limitation," (citing Am. Container Inc. v. Plastipak Packaging, Inc., 415 F.3d 1335 (Fed. Cir. 2005)). The Federal Circuit therefore affirmed both the claim construction and the final judgment.

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