Statements Describing the Preferred Embodiment or Only Part of the Invention Are Not a Clear Disavowal of Claim Scope

The patentee sued for infringement of various claims related to various electrical devices. The district court construed several related claim terms as requiring that the electrical devices be made by a particular process. Based on the district court’s construction, the parties stipulated to non-infringement. On appeal, the patentee argued that the district court erred by incorporating the particular process into the claim language. The Federal Circuit held that the district court’s construction was erroneous, vacated the judgment of non-infringement, and remanded.

The claims are construed by analyzing the claims in view of the specification. The patentee can narrow the claim language either by providing a specific definition of a claim term or by disavowing claim scope. In this case, the claims were not explicitly limited to the particular process. The alleged infringer argued that the patentee had disclaimed claim scope, which did not include the particular process.

A disclaimer of claim scope has to be clear and unmistakable. The specification described the particular process as “one technique,” an “example,” and a way to carry out the invention. These statements did not limit the electrical device, as opposed to the particular process, and were thus not sufficient to limit claim scope.

The court also considered whether the specification’s description of the “present invention” limited the invention to the particular process. Although a patentee can limit the scope of the invention through use of the “present invention,” the patentee in this case did not limit its claims. In this case, the patentee did not use the “present invention” to describe the invention as a whole. The patentee also did not uniformly use the “present invention” to describe electrical devices made with the particular process.