Last Month at the Federal Circuit
Last Month at the Federal Circuit

August 2012

Prosecution Disclaimers Must Be Clear and Unmistakable to Limit Claim Scope


Judges:  Rader, Wallach, Fogel (author, district judge sitting by designation)
[Appealed from E.D. Va., Senior Judge Hilton]

In 01 Communique Laboratory, Inc. v. LogMeIn, Inc., No. 11-1403 (Fed. Cir. July 31, 2012), the Federal Circuit vacated the district court’s SJ of noninfringement in favor of LogMeIn, Inc. (“LogMeIn”) because the district court erred in construing the claim term “location facility.”

01 Communique Laboratory, Inc. (“Communique”) owns U.S. Patent No. 6,928,479 (“the ’479 patent”) directed to enabling one computer to access another via the Internet.  All of the claims asserted by Communique against LogMeIn require “a locator server computer . . . including a location facility.”  During claim construction, the district court concluded that the “location facility” must be located on a single physical computer, relying primarily on a “perceived” disclaimer by Communique during reexamination.  Slip op. at 5.   Because LogMeIn’s system did not contain a single component that performed all the claimed functions of the location facility, the district court granted SJ of noninfringement in favor of LogMeIn.  Id.

On appeal, LogMeIn argued that the district court’s claim construction was supported by claim language referring to the “locator server computer” in the singular, e.g., “a locator server computer linked to the Internet, its location on the Internet being defined by a static IP address.”  Id. at 7 (citation omitted).   LogMeIn also argued that Communique disclaimed distribution of the location facility among multiple computers during reexamination to avoid prior art.


“An ambiguous disclaimer, however, does not advance the patent’s notice function or justify public reliance, and the court will not use it to limit a claim term’s ordinary meaning.”  Slip op. at 9 (quoting SanDisk Corp. v. Memorex Prods., Inc., 415 F.3d 1278, 1287 (Fed. Cir. 2005)).

The Court disagreed.  Initially, the Court observed that while the district court considered the location facility to be a “device,” both Communique and LogMeIn agreed that the location facility was software that runs on the locator server computer.  The Court noted its well-established precedent of interpreting the words “a” or “an” in a patent claim as meaning one or more and nothing in the record necessitated a departure from this rule.  Failing to find “a clear intent” to limit the scope of claims of the ’479 patent and given that the patent specification expressly discloses that the locator server computer “may comprise one or more computers, as is well known,” the Court found LogMeIn’s textual argument unavailing.  Id. at 8-9 (citation omitted).

The Court considered whether Communique had effectively disclaimed having more than one “device” perform the function of the location facility.  “When the patentee makes clear and unmistakable prosecution arguments limiting the meaning of a claim term in order to overcome a rejection, the courts limit the relevant claim term to exclude the disclaimed matter.”  Id. at 9 (quoting SanDisk Corp. v. Memorex Prods., Inc., 415 F.3d 1278, 1286 (Fed. Cir. 2005)).  During an inter partes reexamination of the ’479 patent initiated by Citrix Systems, Inc. (“Citrix), Communique’s expert indicated that “the location facility creates a communication channel . . . and that this ‘create’ limitation would not be satisfied by a location facility ‘that is simply used by some other component that creates the communication channel.’”  Id. at 10 (citation omitted).  Rather than finding a prosecution disclaimer, the Court found that the expert merely “differentiat[ed] between technology in which the location facility itself creates the communication channel and technology in which some component other than the location facility creates the communication channel.”  Id.  Because the expert’s opinion did not address whether the location facility must be contained on a single locator server, the Court held that the expert’s opinion failed to give a “clear and unmistakable” argument amounting to a prosecution disclaimer.

LogMeIn contended that prosecution disclaimer applied based on either representations to the PTO made by the same expert in order to avoid prior art rejections, or cancellation of dependent claims that defined the “locator server computer” to encompass multiple computers.  After examining the expert’s statements, the Court found no unambiguous disclaimer and noted that the district court’s understanding of the location facility as a “device” as a possible reason for the misinterpretation.  The Court also did not consider the cancellation of the dependent claims to effect a disclaimer; the cancellation of dependent claims defining the locator server computers to encompass multiple computers was necessitated by a rejection based on the written description requirement of 35 U.S.C. § 112 and not out of any desire to disclaim scope.  Moreover, the Court emphasized an explicit finding by the examiner that “the specification of the ’479 Patent clearly defines that the server computer comprises one or more computers,” contrary to LogMeIn’s contentions.  Id. at 13 (citation omitted). 

Accordingly, the Court construed the term “location facility” as “[s]oftware on a locator server computer,” wherein “[t]he locator server computer may comprise one or more computers, and the location facility may be distributed among one or more locator server computers.”  Id. at 13-14.  Because the district court’s grant of SJ to LogMeIn was based on an erroneous claim construction, the Court vacated the SJ of noninfringement and remanded for further proceedings.