Phillips v. AWH: Practical Pointers on the Use of Intrinsic and Extrinsic Evidence

The Federal Circuit's <i>en banc</i> decision in <i>Phillips v. AWH Corp.</i>, 415 F.3d 1303 (Fed. Cir. 2005), provides a reminder, for patent prosecution attorneys and patent litigators alike, of the types of evidence that can be used to support a patent claim construction. In short, intrinsic evidence ' namely, the claim language, specification and prosecution history ' remains the primary source materials for interpreting patent claims. On the other hand, extrinsic evidence ' namely, dictionaries, treatises and expert testimony ' may not have the same persuasive status previously accorded by the Federal Circuit's decision in <i>Texas Digital Sys., Inc. v. Telegenix, Inc.</i>, 308 F.3d 1193 (Fed. Cir. 2002). Nonetheless, extrinsic evidence retains its role in helping to explain the meaning of claim terms as understood by a person of ordinary skill in the art. Extrinsic evidence also can be useful to explain the "context" of the invention that informs any claim construction.

21 minute read February 01, 2006 at 03:06 PM

By

Jonathan S. Caplan And Mary W. Richardson