Twisting a Nose of Wax While Splitting Hairs

| Karen Cassidy Selvaggio


Before Stoll, Reyna, and Schall. Appeal from U.S. District Court for the Northern District of Texas.

Summary: When a party distinguishes technology in the prior art to preserve validity, that same technology may not simultaneously be grounds for infringement when in an accused product.

CommScope filed suit against Dali alleging infringement of five of CommScope’s patents. Dali counterclaimed, alleging CommScope infringed two of Dali’s patents. The jury rendered verdicts of infringement, no invalidity, and damages for both parties. CommScope and Dali each appeal following the district court’s denial of their respective motions for judgment as a matter of law, a new trial, and attorney’s fees.

Dali’s ‘521 patent at issue described a system and method for digital predistortion of signals. Specifically, the patent describes an operating mode requiring: “switching a controller off to disconnect signal representative of the output of the power amplifier.” The district court construed this term to mean “[s]witching a controller to a nonoperating state to disconnect signal representative of the output of the power amplifier.”

First, the Federal Circuit rejected Dali’s challenge to the district court’s claim construction noting that an argument that is made only in a footnote is forfeited. Even if the argument had been properly raised, it was insufficiently developed. Seeing no meaningful challenge from Dali, the Federal Circuit adopted the district court’s construction.

Second, the Federal Circuit turned to noninfringement, finding that Dali cited no evidence showing that the switch, the controller, or a combination of the two are put into a “nonoperating state” in the accused product. Moreover, CommScope argued that Dali did not dispute testimony from CommScope’s expert that both the switch and controller are continuously operating, instead explaining why that operation infringes. The Federal Circuit rejected Dali’s argument that this distinction was “splitting hairs.”

Third, the Federal Circuit determined that Dali’s infringement argument could not stand in light of its arguments of no anticipation. Dali distinguished the prior art by arguing that the patent requires “a controller that controls a switch and places itself and the switch in a non-operating state in order to disconnect the output from the training circuit.” However, in its argument that CommScope’s technology infringed the patent, Dali argued that “CommScope’s premise that the controller itself must be turned off is . . . literal nonsense.” The Federal Circuit found the case fell squarely within the principle that “a patent may not, like a nose of wax, be twisted one way to avoid anticipation and another to find infringement.” Accordingly, the Federal Circuit reversed the denial of CommScope’s motion for JMOL of noninfringement and affirmed the denial of CommScope’s motion for JMOL of invalidity.

Editor: Paul Stewart