By a 6-4 vote, the en banc U.S. Court of Appeals for the Federal Circuit tackled one of the most contentious issues in patent law, reaffirming in Lighting Ballast Control v. Philips Electronics North America, 2014 WL 667499 (Fed. Cir. Feb. 21, 2014), that trial court claim construction rulings will be reviewed without deference in the circuit court.
Claim construction—the interpretation of the meaning of terms in the patent claims—is a central issue (sometimes the central issue) in many patent litigations. In some actions, a claim interpretation ruling can mean the difference between an easy infringement case and an impossible one. The Supreme Court held in Markman v. Westview Instruments, 517 U.S. 370 (1996), that claim construction “is a matter of law reserved entirely for the court,” rather than a jury issue. Following on Markman, in Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998), the en banc Federal Circuit held that district court claim construction rulings are reviewed de novo on appeal, meaning that findings of the trial court—including findings on factual issues—receive no deference in the circuit court.
