Interpreting Patent Claims: Patent Drafters Say What They Mean, But Do They Mean What They Say?

Seemingly relegating the patent specification to second-class status, the panel in Housey Pharm., Inc. v. Astrazeneca UK Ltd., 364 F.3d 1348 (Fed. Cir. 2004), began its analysis by stating that there is a “heavy presumption” that the language in a claim “carries its ordinary and customary meaning.” Based on the court's approach, this ordinary definition can be determined by looking in dictionaries. This panel stated that in order to overcome this “heavy presumption” that the dictionary definition is the controlling interpretation, the intrinsic evidence would have to “clearly disavow” the ordinary meaning. As the dissent put it, the majority categorized intrinsic evidence as an “also-ran” in claim construction.

In almost direct contrast, the panel in Vanderlande Indus. Nederland BV v. Int'l Trade Comm'n, 366 F.3d 1311 (Fed. Cir. 2004), began its analysis by stating that the “intrinsic evidence is the most significant source of the legally operative meaning of disputed claim language.” Id. at 1318. Although it did not state that the specification of the patent at issue clearly set forth a special definition, the panel concluded that it was “doubtful whether any extrinsic evidence could contradict or overpower the meaning evident from the written description.” Id. at 1722.