Full Scope of Patent Claims Must Be Enabled at the Time of Filing

The headline of this post, a truism of patent law to be sure, is nicely illustrated by the Federal Circuit’s opinion in Convolve, Inc. v. Compaq Computer Corp., No. 2012-1074 (July 1, 2013). After an inventor admitted in testimony that he had been unable to implement claimed subject matter in certain contexts until nine years after the application for the patent was filed, the District Court held the relevant claims invalid under 35 U.S.C. § 112. The Federal Circuit affirmed this holding.

The claims at issue were directed to improving “seeks” in computer hard drives. A “seek” is the process of locating data on a hard drive. The claims of United states Patent No. 4,916,635 were directed to a method for “generating an input to a system to minimize unwanted dynamics in the system response.” The claims covered both “long seeks,” where data was stored in tracks on the hard drive that were far apart, as well as “short seeks,” where data was stored in tracks that were close together.

The application for the ’635 patent was filed in 1988. The District Court invalidated the ’635 patent claims based on an inventor’s testimony “that he was unable to implement the asserted claims for ‘long seeks’ in disk drives in 1992.” The District Court reasoned that “given the breadth of the asserted claims of the ’635 patent, and because long seeks are a fundamental requirement for proper hard drive functionality, the patent failed to enable long seeks.”

The plaintiff-appellant argued that because “the claims of the ’635 patent have been implemented in other physical systems, and for short seeks on some disk drives, it is enabling for all disk drives.” The Federal Circuit disagreed. The District Court had found, and the court here agreed, that “the claims purport to cover inputs into any and all physical systems, including disk drives.” The inventor’s testimony was fatal: he “conceded that four years after the filing of the patent application he was unable to fully implement the ’635 patent’s method on disk drives.” Only nine years after filing did he solve this problem. Further, there was no reason to question the District Court’s finding that “that long seeks were, and are, necessary for hard drive functionality.”

The lesson here, of course is that in seeking “broad claim language,” a patent applicant puts itself “at the peril of losing any claim that cannot be enabled across its full scope of coverage.” In fact, the court noted that part of the purpose of the enablement requirement is to discourage over-broad claiming, and to encourage follow-on applications when improvements are made.

This opinion also touched deeply on trade secrets and indirect infringement questions not covered in this post. The Federal Circuit affirmed the District Court’s finding that the defendants had not misappropriated trade secrets, but reversed and vacated a finding of non-infringement regarding a second patent, discussing the requirements for indirect infringement at some length.

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