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Claim Construction: First Consult the Specification or Technical and General Purpose Dictionaries?
Brian P. Furrer (U.S. Patent Attorney)
At present in US patent law there is an issue with respect to construing the terms of patent claims. The issue is what should be the primary source for determining the meaning of terms used in the claims: (1) evidence intrinsic to the patent, such as the patent specification, or (2) should intrinsic evidence be consulted only after the ordinary and customary meaning of claim terms to persons skilled in the pertinent art is determined?
As remarked by the US Court of Appeals for the Federal Circuit in September 2004 in its decision in Astrazeneca et al. v. Mutual Pharmaceutical, US case law on this subject is "unfortunately complex and inconsistent." A long line of decisions hold that evidence intrinsic to the patent, especially the patent specification, is the primary source for determining claim meaning. Some recent cases suggest that the intrinsic record, except for the claims, should be consulted only after the ordinary and customary meaning of claim terms to persons skilled in the pertinent art is determined.
As further noted by the court, resolution may be approaching due to the case of Phillips v. AWH Corp. et al. In the Phillips case, the Federal Court of Appeals has ordered a rehearing en banc to broadly address claim construction. En banc means that all of the judges of the Federal Court of Appeals will rehear the case, rather than the usual three judge panel.
Additionally, the court in the Phillips case has invited the parties and other interested parties to submit briefs specifically addressing whether a claim term should be interpreted by referring primarily to technical and general purpose dictionaries and similar sources, or to primarily consult the patentee's use of the term in the specification.
In addition, the court asked if both sources are to be relied upon, in what order should each source be consulted? In this regard, the court listed several questions dealing with claim construction, such as how to construe a term where there are several dictionary meanings for that term, the role of prosecution history, when should a claim term be construed narrowly to avoid invalidity, and other questions. The complete list of questions asked by the court is here.
The court issued the order for an en banc rehearing in the Phillips case in July 2004. According to the court's order, oral argument will be scheduled by a later order. Most likely a written decision will not be issued by the court for several months and perhaps for not more than a year.
In the meanwhile the patent bar remains very interested in how the court will resolve this issue. For now, patent drafters should probably strive to use terms in the specification and claims that are consistent with the definitions in dictionaries and other references. In that way, the terms used in the claims should be construed to have the meaning intended by the patent drafter regardless of how the Court of Appeals for the Federal Circuit resolves the questions in the Phillips case.