Phillips v. AWH Corporation, et al.
The specification necessarily informs the proper construction of the claims.
The CAFC vacated an earlier judgement by a panel of the court, and granted a rehearing en banc. Phillips had invented modular, steel-shell panels that may be welded to form vandalism-resistant walls. Claim 1 of the Phillips patent recites “further means disposed inside the shell for increasing its load bearing capacity comprising internal steel baffles extending inwardly from the steel shell walls.”
Phillips alleged trade secret misappropriation and patent infringement. The infringement issue revolved around the meaning of the term “baffles.” In particular, the district court had previously ruled that the “baffles,” as construed in light of the specification, must extend inward at an oblique or acute angle to the wall face. Under this construction, Phillips could not prove infringement.
The issue on appeal, with respect to patent infringement, was to what extent the court should rely upon a patent’s specification in seeking to ascertain the proper scope of claims?
In describing the basic standards, the court stated that the words of a claim “are generally given their ordinary and customary meaning,” which is “the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention.” Importantly, the person of skill in the art is deemed to read the claims in the context of the entire patent, including the specification.
The court emphasized the importance of the specification in claim construction. In light of the statutory directive of 35 U.S.C. § 112, para. 1, the “specification necessarily informs the proper construction of the claims.” For instance, the specification may reveal special definitions given to claim terms, or even a disavowal of claim scope. In fact, “the specification is the single best guide to the meaning of a disputed term.” Therefore, the court states, it is “entirely appropriate for a court, when conducting claim construction, to rely heavily on the written description for guidance as to the meaning of the claims.”
The court briefly describes the role of prosecution history in claim construction. Although stating that prosecution history may be considered, the court described it as often less useful because of a lack of clarity in comparison to the specification.
More importantly, the court addressed the role of extrinsic evidence, e.g. dictionaries and treatises, in claim construction. The court stated that there is no guarantee that a term is used in the same way in a treatise or dictionary as it is by the patentee. Although dictionary and treatise definitions may have value when it comes to better understanding the underlying technology, they may only be used to construe clams when the definition does not contradict definitions found in or ascertained from the specification.
Thus, claims must be construed so as to be consistent with the specification, and extrinsic evidence is relegated to a much lesser role.