In a decision that some may regard as blurring the distinction between anticipation and obviousness, U. S. Court of Appeals for the Federal Circuit found that a broad range anticipated a narrow range that lacked “criticality”. ClearValue Inc. v. Pearl River Polymers Inc., Case No. 11-1078 (Fed. Cir. Feb. 17, 2012)(Moore, J.). The Federal Circuit reversed a jury verdict that ClearValue’s patent was not invalid as anticipated under 35 U.S.C. § 102. According to the Court, the verdict was not supported by substantial evidence because the basis for finding lack of anticipation was expert testimony that the prior art taught away from the claimed subject matter. The Court explained that “teaching away” evidence, while applicable to an obviousness analysis, was not relevant to an anticipation analysis.

The ClearValue patent claimed a process for the clarification of water of raw alkalinity less than or equal to 50 ppm by chemical treatment. The prior art, Hassick, disclosed the same process for clarifying water but with alkalinity of 150 ppm or less. According to the Court, since ClearValue did not argue that the 50 ppm limitation in its claim was “critical,” or that the claimed method worked differently at different points within the prior art range of 150 ppm or less, its claim was anticipated.

The Court distinguished an earlier case, Atofina v. Great Lakes Chem. Corp. (IP Update, Vol. 9, No. 4) that reached the opposite result, concluding that claims directed to the narrow range were patentable. In Atofina, the claims were directed to a method of synthesizing a compound within a narrow numerical temperature range, while the prior art disclosed the synthesis within a broader temperature range that included the narrower range. During prosecution, Atofina described its claimed narrower temperature range as “critical,” and its patent stated that problems occur when operating outside of the narrower range.

In distinguishing this case from Atofina, the Court explained that the evidence in Atofina “showed that one of ordinary skill would have expected the synthesis process to operate differently outside the claimed temperature range, which the patentee described as ‘critical’ to enable the process to operate effectively.”

Practice Note: Analyses involving the “expectation” of a skilled artisan and “criticality” are traditionally used in connection with an obviousness inquiry. However, in this case the Federal Circuit has applied a similar analysis to anticipation.

This decision underscores the importance of having meaningful (i.e., critical) claim limitations to distinguish the prior art, for both anticipation and obviousness. It also counsels for the presentation of statements as to the criticality of a claimed range in the written description.