Dictionary Dethroned: Phillips v. AWH Corporation

The Phillips case hinged on the meaning of the claim term “baffle” in U.S. Patent No. 4,677,798, relating to vandalism-resistant modular wall panels invented by Edward Phillips. The Federal Circuit disagreed with the district court's claim construction and reversed the summary judgment of noninfringement. In so doing, the Federal Circuit overturned an earlier determination by a three-judge panel of the same court, in which the judges agreed with the district court that Phillips' patent was limited to baffles positioned at certain angles and, thus, that his patent was not infringed.

Judge William Curtis Bryson writing for the majority in Phillips laid down ground rules for interpretation of patent claims. The court turned away from prior case law, namely Texas Digital Systems Inc. v. Telegenix Inc., 308 F.3d 1193 (Fed. Cir. 2002), which suggests that dictionaries may be a better starting point for claim construction than the specification and prosecution history. The Federal Circuit explained that Texas Digital's focus on dictionary definitions improperly limited the role of the specification in claim construction to serving merely as a check on the dictionary meaning of a claim term. Citing Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576 (Fed. Cir. 1996), the court stated that the Texas Digital approach “is inconsistent with our rulings that the specification is 'the single best guide to the meaning of a disputed term,' and that the specification 'acts as a dictionary when it expressly defines terms used in the claims or when it defines terms by implication.'” The court further stated that the Texas Digital line of cases “has been improperly relied upon to condone the adoption of a dictionary definition entirely divorced from the context of the written description.”