In Lighting Ballast Control LLC v. Philips Electronics North America Corp., Appeal No. 12-1014, the Federal Circuit sitting en banc reinstated the previous panel decision and upheld the standard of de novoreview of claim construction enunciated in Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc).

The Federal Circuit granted en banc a petition by plaintiff-appellee Lighting Ballast to reconsider the holding ofCybor, which established de novo review for issues of claim construction. This new en banc decision addresses: (a) whether the Federal Circuit should overrule Cybor; (b) whether the Federal Circuit should afford deference to any aspect of a district court’s claim construction; and, if so, (c) which aspects should be afforded deference.

The Federal Circuit, divided 6-4, upheld the Cybor standard of de novo review based largely on stare decisis.Accordingly, the Federal Circuit reinstated the panel’s decision reversing the district court’s construction, where the district court had construed a “voltage source means” limitation as not invoking 35 U.S.C. § 112, sixth paragraph.

Judges O’Malley, Rader, Reyna, and Wallach dissented, arguing that claim construction requires district courts to resolve questions of fact. Consequently, the dissent argued that Cybor misapprehends Supreme Court precedent, including Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), and contradicts Fed. R. Civ. P. 52(a)(6), which requires deference to district court findings of fact.