Because the claims, specification, prosecution history, and prior art all suggested a uniform meaning of the claim term, and because no “special definition” was provided, the patentee had not acted as his own lexicographer.

The Laryngeal Mask Co. Ltd. v. Ambu A/S, No. 2010-1028, -1062 (Fed. Cir. Sept. 21, 2010).

The patentee sued for infringement of a patent claiming laryngeal mask airway devices. The district court construed the “backplate” limitation as requiring a tube joint. Because the district court concluded that the alleged infringer’s products did not have a tube joint, the district court granted summary judgment of noninfringement. The district court also granted summary judgment that the patent did not satisfy the written description requirement. The patentee appealed, and the Federal Circuit reversed.

As to claim construction, recognizing the closeness of the case, the Federal Circuit held that the patentee had not acted as his own lexicographer. The specification did not contain any “special definition” for the term. Despite the fact that the specification was “replete with discussion of a tube joint” and although the preferred embodiment contained a tube joint as part of the backplate, that was not sufficient to require every backplate to have a tube joint. Moreover, the summary of the invention disclosed a backplate that did not necessarily have a tube joint. Further, during prosecution, the patentee deleted language requiring the backplate to have a tube joint. The Federal Circuit also found that other prior art patents by the same inventor had used a backplate without requiring a tube joint, thereby persuasively showing that backplates were not necessarily understood to have a tube joint. Accordingly, summary judgment of noninfringement was reversed.

As to written description, the Federal Circuit found that there were material issues of fact as to the interpretation of the specification that precluded summary judgment of invalidity, and therefore reversed.

A copy of the opinion can be found here.