Lighting Ballast Control LLC v. Philips Elecs. N. Am. Corp.

Lighting Ballast's argument that the assessment of expert testimony and other factual questions, which are often raised during claim construction, justified a more deferential standard of appellate review did not provide a compelling justification for abandoning the current de novo standard applied to claim construction appeals.

Opinion (Newman): Following the Federal Circuit’s de novo review of the district court’s claim construction, Lighting Ballast appealed to the Federal Circuit en banc challenging the de novo standard of review applied to appeals of claim construction, established in Cybor Corp. v. FAS Tech., Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc). Because of the enhanced predictability and efficiency the doctrine of stare decisis provides, a court will not depart from the doctrine absent “compelling justification.” Lighting Ballast and several amici argued that claim construction is an essentially factual inquiry and can involve assessment of expert credibility, and therefore should be subject to deferential review on appeal, instead of being reviewed as a question of law. While the en banc court agreed that the assessments of experts and other factual considerations may be important elements in the determination of what a skilled person in the relevant art would have understood a patent claim to mean, ultimately “[c]laim construct is a legal statement of the scope of a patent right.” Accordingly, although a court may benefit from the testimony of experts and the knowledge contained in treatises, the assistance of those sources does not convert claim construction into a question of fact. The court also noted that the consistency and stability that stare decisis provides are the same concerns that compelled the creation of the Federal Circuit. Given the often multi-jurisdictional nature of modern patent litigation, a more deferential standard of review could require the Federal Circuit to affirm dissimilar constructions of the same patent’s claims when those differing constructions are not clearly erroneous. Affirming dissimilar constructions would undermine the purpose underlying the Federal Circuit’s exclusive patent jurisdiction. Because Lighting Ballast was unable to provide a compelling justification for abandoning the de novo standard established in Cybor, the court refused to modify the standard applied to appellate review of claim construction.