On October 15, 2014, the U.S. Supreme Court expressed skepticism regarding an exception to Rule 52 for patent appeals. Teva Pharm. USA, Inc. v. Sandoz, Inc., No. 13-854, U.S., oral argument 10/15/14.
In general, an appeals court will review a lower court’s factual findings for clear error, and typically an appeals court will not overturn a lower court’s decision unless certain that the lower court made a mistake. However, Universal Lighting argued that claim construction is a matter of law, and therefore de novo review is appropriate except where there are “disputed historical facts.” Lighting Ballast Control LLC v. Philips Elecs. N. Am. Corp., 744 F.3d 1272 (Fed. Cir. 2014) (No. 2012-1014), 2013 WL 3816455, at 5.
Taking up the question of whether the term “molecular weight” was indefinite in Teva, the court appeared weary of this exception its form as articulated in Lighting Ballast. As Justice Alito noted on October 15, the answer may hinge on whether claim construction is more like statutory interpretation or more like contract interpretation.