The New 'Material Effect' Test

Majority Opinion

The majority began its analysis by examining the scope of the best mode requirement. The analysis began with a review of In re Brebner, 455 F.2d 1402 (C.C.P.A. 1972), wherein the Court of Customs and Patent Appeals held that the method of making two polymers was not within the scope of the best mode because the invention was the blend of the two polymers, not the starting materials. After reviewing the intervening case law, the Bayer majority noted that the scope of the best mode requirement is determined by the scope of the claims. However, the majority then reviewed those cases where the Federal Circuit held patents invalid for failing to disclose the best mode. Four of the seven cases issued during the late 1980s and early 1990s. During this period, the Federal Circuit had the broadest interpretation for the best mode requirement, extending beyond the scope of the claimed invention. In Northern Telecom, Inc. v. Datapoint Corp., 908 F.2d 931 (Fed. Cir. 1990), for example, the Court found that the patent at issue was invalid for failing to disclose the inventor's preferred audio cassette for use in the claimed invention, even though the claims covered only the device and not the audio cassette. In Bayer, however, the majority held that, in order to satisfy the best mode requirement, an inventor's preferred mode must be disclosed if it materially affects the properties of the claimed invention. This includes preferred modes outside the scope of the claims. Applying this standard, the Court ultimately found that the best mode was satisfied because the inventor's preferred mode did not affect the properties of the claimed invention.