Earlier this year, the Supreme Court finally resolved an issue that divided the U.S. Court of Appeals for the Federal Circuit (CAFC) for nearly 20 years. In Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, the Supreme Court unanimously held that a trial court’s underlying factual determinations with respect to extrinsic evidence used in patent claim constructions must be reviewed on appeal under the clearly erroneous standard rather than de novo.1
Before the Supreme Court’s decision in Teva, the CAFC reviewed patent claim constructions de novo, including any allegedly fact-based questions relating to the trial court’s claim construction. As a result, it was quite common for the CAFC to reverse a trial court’s claim construction well after the completion of a lengthy jury trial. The case would be remanded to the trial court (unless the CAFC determined that the error would not have affected the judgment), in some instances leading to an entirely new trial on the merits (and, perhaps, another appeal to the CAFC). After Teva, many hope that CAFC claim construction reversals will be less frequent, particularly when litigants are able to introduce extrinsic evidence such as expert witness testimony into the claim construction process.
The CAFC has now had an opportunity to reconsider on remand not only its decision in Teva, but also Lighting Ballast Control LLC v. Philips Electronics N.A. Corp. which the Supreme Court also remanded to the CAFC for reconsideration in light of Teva.
In Teva, the CAFC held firm and once again reversed the trial court’s claim construction. In Lighting Ballast, on the other hand, the CAFC changed course and affirmed the trial court’s claim construction, arguably giving more deference to the trial court’s decision than mandated by the Supreme Court. These two decisions, by different panels at the CAFC, demonstrate that though the issue of whether deference should be given to the trial court’s underlying factual findings has been resolved, the new challenge may be determining what is and is not a factual finding by the trial court.
In Part I we look at how the CAFC dealt with Teva on remand. In Part II (coming soon) we will examine the decision on remand in Lighting Ballast.
Patent claim construction2 and appellate review
The scope of a patent is defined by its claims, and construing and construing the meaning of patent claims is a question of law for the court — not a jury — to decide. Markman v. Westview Instruments, Inc., 517 U.S. 370, 390-91 (1996). Claim terms are given their ordinary and customary meaning to a person of ordinary skill in the relevant art, interpreted in the context of the patent as a whole. A court will also considers the prosecution history of the patent, with the claims, specification and prosecution history referred to as the “intrinsic evidence.” In some instances (but not all) a court will consider “extrinsic evidence” — evidence outside of the patent itself — if the court believes such evidence will aid in the claim construction. This extrinsic evidence typically includes things such as dictionaries, treatises and expert witness testimony.
Because patent claim construction is a question of law, the appellate court conducts a de novo review of the construction of a claim, without giving deference to the trial court. Claim constructions are sometimes based, in part, on underlying factual findings by the trial court, such as determining the meaning of a technical term in the relevant art based on extrinsic evidence (e.g., expert testimony). Findings of fact, however, are normally reviewed on appeal under the clearly erroneous standard — the appellate court will not overturn the trial court’s factual determinations unless it has a “definite and firm conviction that a mistake has been committed.” United States v. United States Gypsum Co., 333 U.S. 364, 395 (1948). Nevertheless, prior to the Supreme Court’s decision in Teva, the CAFC reviewed patent claim constructions de novo, including any allegedly fact-based questions relating to the trial court’s claim construction.
In Teva Pharmaceuticals USA, Inc. v. Sandoz Inc., the Supreme Court held that though the CAFC must continue to review de novo a trial court’s ultimate interpretation of the patent claims, any underlying factual findings of the trial court must be reviewed using the clearly erroneous standard. The Supreme Court also established a clear delineation between a trial court’s evaluation of intrinsic and extrinsic evidence. “[W]hen the district court reviews only evidence intrinsic to the patent (the patent claims and specifications, along with the patent’s prosecution history), the judge’s determination will amount solely to a determination of law, and the court of appeals will review that construction de novo.” 135 S. Ct. 831, 841. However, when the trial court must “consult extrinsic evidence in order to understand, for example, the background science or the meaning of a term in the relevant art during the relevant time period,” such “subsidiary factfinding[s] must be reviewed for clear error on appeal.” Id.
The court reiterated, however, that there remains a clear distinction between subsidiary findings of fact, reviewed for clear error, and the ultimate legal construction of a claim term that must be reviewed de novo on appeal. “[E]xperts may be examined to explain terms of art, and the state of the art, at any given time, but they cannot be used to prove the proper or legal construction of any instrument of writing.” Id. Thus, though “in some instances, a factual...
