Narrow Claim Construction Relying on Ambiguous Prosecution History Statements Failed to Meet the High Standard for Prosecution Disclaimer

In Avid Technology, Inc. v. Harmonic, Inc., No. 15-1246 (Fed. Cir. Jan. 29, 2016), the Federal Circuit held that the district court erred when it narrowly construed a claim term based on statements made during prosecution.

During prosecution of the asserted patent, Avid distinguished the claimed invention over prior art by noting that, in the claimed system, “[c]lients do not issue requests to a central controller that in turn identifies storage units that store the data and issues requests to storage units.” The district court found that this and other statements amounted to a disclaimer, instructing the jury that “systems with independent storage units . . . cannot use a central controller that identifies the storage unit on which data is stored in response to client requests.”

The Federal Circuit disagreed. The Court explained: “When prosecution history is used solely to support a conclusion of patentee disclaimer, the standard for justifying the conclusion is a high one.” Accordingly to the Court, the district court read Avid’s statements too narrowly. In particular, the Court explained that Avid’s statements during prosecution excluded a central controller if it performs both of two functions (i.e., identifying storage units and issuing requests)—not if it performs only one of those functions. Although the Court found that infringement as a whole must be retried, because Harmonic did not suggest an alternative claim construction or argue noninfringement based on an alternative claim construction, satisfaction of this claim requirement was settled.