Claim construction is arguably the most crucial aspect of a patent infringement case. As some prominent legal scholars and practitioners note, “[claim construction] is central to evaluation of infringement and validity, and can affect or determine the outcome of other significant issues such as unenforceability, enablement, and remedies.” To date, there have been three important claim construction cases. In Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), the Supreme Court, while not categorizing claim construction as a question of fact or law, nonetheless ruled that courts are better suited than juries for interpreting patent claims. Then, in Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998), the Federal Circuit held that “claim construction, as a purely legal issue, is subject to de novo review on appeal.” Finally, in Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005), the Federal Circuit, “after consideration of the matter,” decided not to address the issue and therefore “leave undisturbed [its] prior en banc decision in Cybor.”
On September 13, 2013, the Court of Appeals for the Federal Circuit, in Lighting Ballast Control LLC v. Philips Electronics North America Corp., had convened en banc “to reconsider the principle of de novo review of claim construction … and the following questions:”
- Should the court “overrule Cybor?”
- Should the court “afford deference to any aspect of a district court’s claim construction?”
- “If so, which aspects should be afforded deference?”
The main claim construction issue in Lighting Ballast was whether the particular claim phrase “voltage source means providing a constant or variable magnitude DC voltage between the DC input terminals” (U.S. Patent No. 5,436,529) invoked means-plus-function claiming under 35 U.S.C. §112(f). The district court held that the relevant claims should not be construed under § 112(f) but instead should be given their plain meaning. On appeal, the Federal Circuit reversed, following the Cybor rule in applying de novo review to the claim construction issue. Under de novo review, the court found that the better interpretation of the claims limited their scope to means-plus-function claiming under § 112(f), but because the asserted patent did not contain any corresponding structure in the specification, the relevant claims were held invalid for indefiniteness. The petition for en banc rehearing by Lighting Ballast followed. It was anticipated that the en banc Federal Circuit would bring more certainty to patent litigation by providing for a more consistent and predictable claim construction process.
The long-awaited decision, Lighting Ballast Control LLC v. Philips Electronics N.A. Corp. (Fed. Cir. 2014) (En banc), was issued on February 21, 2014. Despite the anticipation, the en banc panel basically reiterated the status quo – a divided court reaffirmed 6-4 the rule that claim construction is a question of law subject to de novo review on appeal. Writing for the majority, Judge Newman (joined by Judges Lourie, Dyk, Prost, Moore, and Taranto) stated:
On thorough review, we are not persuaded that discarding de novo review would produce a better or more reliable or more accurate or more just determination of patent claim scope. Those who urge change in the Cybor standard have identified no pattern of error, no indictment of inferior results …. Review of claim construction as a matter of law has demonstrated its feasibility, experience has enlarged its values, and no clearly better alternative has been proposed. There has arisen no intervening precedent, no contrary legislation, no shift in public policy, no unworkability of the standard.
Is this a good result for the patent system? While the split court and the importance of the issue makes Supreme Court review possible, as it stands one of the most important procedural issues of patent law remains unchanged. A more deferential standard of review could have increased the certainty of Markman hearing rulings made the trial court – the issue of claim construction would largely be decided by the trial judge rather than affording litigants a second chance for a more favorable result on appeal. However, a deferential standard of review could also have handcuffed litigants with unfavorable claim interpretations made by a district court judge with little interest and expertise in technology and/or patent law and less chance of reversal by the Federal Circuit.
Claim construction is one of the most difficult tasks a district court must face in a patent case. A clear result of Lighting Ballast was that the Federal Circuit will continue to hold power over this difficult problem. However, the decision did little to extinguish the lack of certainty that has continued to plague the claim construction process. It does not help that some recent Federal Circuit decisions are themselves inconsistent in appearing to state a directly competing line of authority to the specification-focused methodology of claim construction reiterated by the en banc Federal Circuit in Phillips – a claim-centric view that elevates the plain and ordinary meaning of claim terms over all other means of interpretation.
In the end, rather than waiting for the courts to bring more consistency and predictability, the best solution might be to place more of the responsibility on the USPTO to improve claim scope and clarity earlier on – at the patent prosecution stage – in order to alleviate some of the burden courts will carry later on during the claim construction process.