The Federal Circuit recently addressed the claim definiteness requirement of 35 U.S.C. §112 (¶2) in the context of means-plus-function claims, holding that a controller circuit shown in the patent specification as a “black box” with no description of its inner circuitry was an adequate disclosure of structure corresponding to the “monitoring means” recited in the claim because an ordinary artisan would have recognized the controller as an electronic device with a known structure. The opinion also addresses the broad discretion of district courts to interpret ambiguous verdict forms. Telcordia Technologies, Inc. v. Cisco Systems, 612 F.3d 1365 (Fed. Cir. 2010).


Telcordia Technologies, Inc. (“Telcordia”) sued Cisco Systems, Inc. (“Cisco”) for infringement of three patents relating to router and switching technology. The district court granted Cisco summary judgment of noninfringement with respect to one patent, but a jury found that Cisco willfully infringed the other two patents and also found that all three asserted patents were valid. The jury additionally awarded Telcordia damages of $6.5 million. Following trial, the district court denied Cisco’s motion for judgment as a matter of law (“JMOL”) with respect to validity of two patents (one by anticipation and the other by indefiniteness) and also ordered the parties to negotiate an ongoing license for Cisco’s continued infringement.

On appeal, the Federal Circuit vacated the judgment that one patent was not anticipated because it was based on an erroneous claim construction, but upheld the summary judgment of noninfringement. The court then turned to the indefiniteness issue.

“Black Box” In Figure Did Not Render Means-Plus-Function Claim Indefinite

One of the patents at issue recited “monitoring means. . . for evaluating the integrity of the multiplexed substrate communications. . . .” The accused infringer (Cisco) had challenged this limitation on grounds of indefiniteness under 35 U.S.C. §112 (¶2). Cisco asserted that the only structure corresponding to the recited function described in the specification was a controller circuit, but that the disclosure of that circuit was inadequate because it was shown simply as “a black box, i.e., nothing in the figures describe[d] the details of its inner circuitry.” The Federal Circuit disagreed.

“For a means-plus-function claim to satisfy the definiteness requirement, the written description must clearly link or associate structure to the claimed function,” the court explained. The patent at issue satisfied this standard, the court determined, because “claim definiteness depends on the skill of the ordinary artisan.” In light of that level of skill, the absence of internal circuitry alone may not be sufficient to render a claim indefinite. Relying primarily on testimony from Telcordia’s expert and language from the patent’s specification, the court determined that even though the corresponding structure was a “black box” without details of its inner circuitry, the claim was not indefinite because an “ordinary artisan would have recognized the controller as an electronic device with known structure” and “the specification along with the figures shows sufficient structure to define the claim terms for an [ordinary] artisan in the relevant field.”

District Court Had Broad Discretion To Interpret Verdict Form

With respect to damages, the court held that the district court did not abuse its discretion in interpreting the verdict form and granting Telcordia additional relief. Because Telcordia and Cisco together presented three sets of damages numbers, with each side using different royalty rates and royalty bases, and because there was no express statement in the verdict, it was “unclear whether the jury based its award on a lump-sum, paid-up license, running royalty, some variation or combination of the two, or some other theory.” Even though the $6.5 million award was closer to the $5 million proposed by Cisco for past and ongoing infringement than the $75 million proposed by Telcordia for past infringement only, the Federal Circuit determined that district courts, as direct participants in the jury trial process, have broad discretion in interpreting jury verdict forms and that the lower court in this case was well within its discretion in deciding that the jury award was for past infringement only and not for any ongoing infringement.

Dissenting only on indefiniteness, Judge Prost noted that there were two possible components which could be linked to the claimed function and the that the majority’s opinion was that one skilled in the art could, by “process of elimination,” deduce which structure was linked to the claimed function. Disagreeing with the standard used by the majority, Judge Prost stated that “[i]t is not enough . . . that a skilled artisan can follow the clues in the patent and solve the mystery of what structure must perform the claimed function” and that Federal Circuit “precedent requires that the specification clearly link a particular structure with a claimed function.”

Rehearing En Banc Rejected

Cisco petitioned for rehearing en banc. Cisco’s primary point of contention was that indefiniteness should be treated like claim construction, i.e., that it should be decided only by a judge and not a jury. Cisco argued that in the wake of Markman the Federal Circuit has found that indefiniteness is a legal issue just like claim construction and that Federal Circuit decisions such as Atmel Corp. v. Information Storage Devices, Inc., Exxon Research & Eng’g Co. v. United States and Praxair, Inc. v. ATMI, Inc. all strongly support that position. Acknowledging that there is Federal Circuit precedent allowing issues of indefiniteness to be decided by a jury, Cisco argued that such cases represent a “renegade line of authority . . . creating confusion and derailing the otherwise settled principle that judges are responsible for determining whether the scope of claims is sufficiently precise to pass statutory muster.” Although Cisco’s petition was supported by General Motors and Microsoft as amici curiae, it was denied.