Challenging Cybor: Lighting Ballast Control v. Philips Electronics

By Dennis Crouch

Lighting Ballast Control v. Philips Electronics (Fed. Cir. 2013) on petition for en banc rehearing

The patentee in this case has now filed its brief requesting that the court sit en banc and overturn its 15-years-old decision, Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc). In Cybor, the Federal Circuit held that district court claim construction should be given no deference on appeal, facts-be-damned.

The major claim construction issue in the case turns on whether a particular claim phrase should be interpreted under 35 U.S.C. 112¶6. The asserted claim requires a "voltage source means providing a constant or variable magnitude DC voltage between the DC input terminals." U.S. Patent No. 5,436,529. In preparing for a claim construction decision, the district court was presented with evidence on the technology in question and the level of ordinary skill in the art and then made a number of seemingly factual conclusions — The most pertinent conclusion being that a person of skill in the art would interpret the disputed term as covering a class of structures that include "a rectifier, or structure to rectify the AC power line into a DC voltage." Once that factual conclusion was reached, it was easy for the district court to make its claim construction decision that the term was not limited by 112¶6. The district court particularly held that interpreting the term as a means-plus-function limitation would have "exalted form over substance and disregarded the knowledge of a person of ordinary skill in the art." Based upon district court's construction, a jury sided with the patentee in finding infringement.

On appeal, the Federal Circuit reversed that decision – following Cybor and its progeny in holding that the entire claim construction process is reviewed de novo. On de novo review, the appellate panel found that the better interpretation of the claims limited their scope to that available under 112¶6. Further, because the asserted patent did not spell-out how to build a voltage source, the Federal Circuit ruled that the claim was invalid as indefinite.

In its decision, the Federal Circuit held that the lower court decision "concerned only questions of law." Everyone understands that conclusion is wrong but that it a required constructive conclusion based upon Federal Circuit precedent. Of course, the Supreme Court has written on the topic too and found claim construction a "mongrel practice" involving a mixture of fact and law. Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996) (holding for policy reasons that judges, not juries, should decide claim construction).

Why is this important for Lighting Ballast? If the Federal Circuit is able to recognize that the court made some factual conclusions then it will likely give some deference to those conclusions on appeal. And, in this case, that deference may be sufficient to flip the decision back in favor of the patentee.

Read the petition. Download CyborPetition

Briefs in support are apparently due by February 15, 2013. Andrew Dhuey is representing the patentee on appeal.