A patent claim term should be defined by implication only if the specification manifests a clear intent to limit the term by using it in a manner consistent with only one single meaning.

The same claim term was construed in two different ways during concomitant litigations between the parties in the same district court. In the later filed case, the district court granted summary judgment of non–infringement in favor of the accused infringer. The Federal Circuit vacated and remanded.

The patent–in–suit claimed an improved electrical connector that easily snaps into electrical junction boxes through the use of a “spring metal adaptor.” In the earlier filed case, the district court construed “spring metal adapter” to mean “an adaptor made of spring metal.” In the later filed case, the district court construed “spring metal adaptor” to require a “split” in the adaptor to allow the adapter to narrow upon insertion and then “spring” into place.

The accused infringer argued that the term “spring metal adaptor” should be read to mean a metal adapter that performs a springing function. The court disagreed, finding that “[c]onsistent with the ordinary and customary meaning of these words…the adapter must be made of spring metal.” The accused infringer also argued that “spring metal adaptor” should be defined by implication to require a split. “[The Federal Circuit] has, on occasion, supplied a definition by implication, if the specification manifests a clear intent to limit the term by using it in a manner consistent with only a single meaning.” Here, the court did not find such clear intent because: (1) only one of the four embodiments of the patent–in–suit expressly described having an “opening;” (2) importing a split limitation would render other claim limitations superfluous in that some claims required a split while others did not; and (3) the prosecution history indicated that the inventors and the PTO understood that the adaptor could be split or un–split. Because the trial court misconstrued the claim, the court vacated the grant of summary judgment and remanded.

Judge Lourie dissented in part, noting that he believed that the inventors contemplated that their invention exclusively included a spring metal adaptor with a split, and therefore the patentee’s rights should be limited accordingly.

A copy of the opinion can be found here.