Interpreting Change—A Recent U.S. Court Decision Highlights the Importance of Claim Construction and How It Can Affect Your Patents

Claim construction is the process of determining the scope and meaning of patent claims. It is at the heart of all patent disputes in the United States. Before a court or jury can rule on whether a patent is infringed or invalid, the scope and meaning of the claims of the patent must first be decided. U.S. case law on how claims should be construed has been constantly evolving, as courts continue to try to provide some meaningful guidelines. The latest significant leap in this evolution took place in January 2015, when the Supreme Court of the United States changed the standard of appellate review of lower court claim construction determinations, which had been applied by the Federal Circuit for decades. This article provides a brief overview of the law of claim construction, how the new Supreme Court case changed that law, and provides some practical considerations given the current state of the law on claim construction.

OVERVIEW OF CLAIM CONSTRUCTION

The starting point for claim construction is, of course, the words of the claim itself. Claim terms are generally given their ordinary and customary meaning understood by one of ordinary skill in the relevant art at the time of the invention. In other words, what would a person of average knowledge and skill in the relevant technology area think the claim means? Answering this question involves determining the level of skill in the art at the time the invention was made. In U.S. patent litigation, this is typically determined by a judge after considering expert testimony. Once the level of ordinary skill is decided, the claims are read from the perspective of a person with such ordinary skill. The words of the claims themselves can often be clear on their own. For example, if a patent uses both “a hammer” and “a metal hammer” in its claims, the phrase “a hammer” is broader and does not necessarily mean the hammer is made of metal.

If ambiguity remains after reviewing the claim language, the specification of a patent should be consulted next. In particular, the specification may reveal that the patentee has used claim terms in a manner inconsistent with or narrower than their ordinary meaning. The specification may also provide a special definition for a claim term, or may intentionally disclaim a possible meaning.

Along with the specification, a patent’s prosecution history may also shed light on the meaning of claims. Courts have recognized, however, that because the prosecution history reflects an ongoing negotiation process between the patent office and the patent applicant, it may be less clear and less useful than the specification for claim construction purposes. Nevertheless, the prosecution history may demonstrate how the inventor understood the invention and may reveal clear disavowals of claim scope in order to overcome prior art.

The claims, specification, and prosecution history together make up what is called “intrinsic evidence.” A second category of evidence called “extrinsic evidence” may also be used to help further understand the meaning of a claim. These include sources such as expert and inventor testimonies, dictionaries, and technical treatises. Courts have recognized the usefulness of extrinsic evidence, but have stated a clear preference for intrinsic evidence because extrinsic evidence is either created for litigation or not directly related to a specific patent, and therefore seen as generally less reliable. As such, claims should first be construed based on intrinsic evidence. Only when a claim term remains ambiguous after considering the intrinsic evidence may extrinsic evidence be considered.

THE SUPREME COURT’S RECENT DECISION IN TEVA

In U.S. patent litigation, the losing party in the court of first instance (e.g., district courts and the United States International Trade Commission) may decide to appeal one or more findings to the Court of Appeals for the Federal Circuit. Given that claim construction is at the heart of a determining infringement and patent validity, it should come as no surprise that it is an issue commonly raised on appeal. The Supreme Court’s decision in Teva Pharm. U.S.A. Inc. v. Sandoz, Inc., dramatically changed the way the Federal Circuit reviews claim construction determinations.

For decades prior to the Teva decision, the Federal Circuit viewed claim construction as purely a question of law, even though questions of fact may be involved, particularly when weighing extrinsic evidence. As such, claim construction determinations were reviewed de novo, as if the Federal Circuit were the first court to decide the issue. Under the de novo standard of review, no deference was given to the lower court’s decision. Ironically, the Federal Circuit view’s were guided by the landmark Supreme Court decision in Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), which held that the judges, rather than the juries, should construe disputed claims.

The Supreme Court in Teva changed the Federal Circuit’s long-standing practice and now requires it to apply a higher “clearly erroneous” standard of review where claim construction relied on extrinsic evidence. The Supreme Court explained that “when the [lower] 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.” But if the lower court has to rely on extrinsic evidence “to understand, for example, the background science or the meaning of a term in the relevant art during the relevant time period,” the judge’s determination on these facts is reviewed for clear error. The Supreme Court recognized that the trial court judge sometimes needs to consult extrinsic evidence to determine a “subsidiary factual dispute.” After deciding the factual dispute, the trial judge then construes the patent claim in light of the decided facts. Although the ultimate claim construction is a legal question that the appeals court reviews de novo, it can overturn the trial judge’s factual determination only if it is clearly erroneous.

PRACTICAL CONSIDERATIONS BASED ON THE CURRENT CLAIM CONSTRUCTION LAW

The ultimate impact and practical application of the Teva case remains to be seen, but in theory, it should lower the number of claim construction reversals by the Federal Circuit. This would be especially true if more judges in courts of first instance base their claim construction decisions, at least in part, on extrinsic evidence. But then again, it may not affect the reversal rate much at all. For example, in the first Federal Circuit decision following Teva, the court still reviewed the lower court’s claim construction decision under the de novo standard because the trial judge made it clear that she relied only on the intrinsic evidence to render the claim construction. In Re Papst Licensing Digital Camera Patent Litigation, No. 2014-1110, at 8 (Fed. Cir. February 2, 2015). The claim construction in that case was reversed.

Nevertheless, in evaluating one’s own patents or the patents of others, it is important to keep in mind that the scope of the patent may not be as broad as the claim language itself seems to suggest, or as narrow as the specification may suggest. One should consider and focus on all of the intrinsic evidence—the patent claims, specification, and prosecution history.

When it comes to litigation, while the focus for claim construction should still be on intrinsic evidence, it may be advantageous to further support a proposed claim construction with extrinsic evidence, as a lower court judge may look more and more to such evidence to support their decisions.

When prosecuting a patent application, keep in mind that the specification, claims, and submissions to the USPTO create intrinsic evidence that may later affect the scope of the issued claims. Claims should be carefully drafted to avoid ambiguity and special attention should be paid to what is written in the specification. This will undoubtedly take more time and increase costs for preparing the application, but it will pay off in the long run when the time comes to enforce or monetize the patent.

As always, you shold consult with a qualified U.S. patent attorney when questions arise about the scope and interpretation of patent claims. As U.S. patent law constantly evolves, the attorney will be able to provide you with advice based on the most recent developments in the law.