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Applicant Failed to Demonstrate Criticality of Claimed Range to Overcome Obviousness

January 08, 2003

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Last Month at the Federal Circuit - February 2003

Judges: Lourie (author), Bryson, and Dyk

In In re Peterson, No. 02-1129 (Fed. Cir. Jan. 8, 2003), the Federal Circuit found substantial evidence to support the Board’s factual findings and affirmed the Board’s conclusion of obviousness.

On December 28, 1994, Lance G. Peterson and Ioannis Vasatis (collectively “Peterson”) filed U.S. Patent Application No. 08/365,392, which relates to a nickel-base single-crystal superalloy, comprising controlled quantities of rhenium, used in making industrial gas-turbine engines exposed to high temperatures. The claimed composition included, among other elements, “about 1 to 3 percent rhenium, [and] about 14 percent chromium.”

The Examiner rejected the claims as obvious in light of several prior art references, including Shah; Wukusick, either alone or in view of Duhl; and Bieber in view of Wukusick. For each of these three grounds of rejection, the Examiner found a prima facie case of obviousness because of the overlapping ranges of the prior art compositions and the claimed composition. Peterson argued that the prior art did not disclose controlled quantities of rhenium and did not suggest that advantageous properties resulted from his claimed invention. The Board affirmed each ground of the Examiner’s rejection.

In affirming the Board’s decision, the Federal Circuit focused on the rejection based on Shah. Noting that a prima facie case of obviousness typically exists when a claimed range overlaps the ranges disclosed in the prior art, the Court compared Shah’s disclosed ranges to Peterson’s claimed ranges. Shah discloses superalloys having rhenium in a range of 0-7% compared to the claimed range of about 1-3%, and chromium in a range of 3-18% compared to the claimed range of about 14%. Shah’s ranges clearly encompass Peterson’s claimed ranges.

But, Peterson argued, it would not have been prima facie obvious to select the claimed narrower ranges from Shah’s broader ranges. Dismissing this argument, the Court noted the settled case law holding that overlapping ranges establish prima facie obviousness, as do disclosed ranges close enough to the claimed ranges such that one skilled in the art would expect similar properties. Where, as here, the prior art range encompasses the claimed range, the conclusion is more compelling than in cases of mere overlap. Thus, a prior art reference that discloses a range encompassing a claimed range is sufficient to show a prima facie case of obviousness, supporting the Board’s finding of prima facie obviousness.

Peterson failed to rebut the prima facie case by establishing that the claimed range achieves unexpected results relative to the prior art range. Based on examples in the specification, substantial evidence supported the Board’s finding that the addition of rhenium, neither in the lower portion of the range (1%) nor in the upper portion of the range (3%), yields unexpected results.

While Peterson could have also rebutted the prima facie case by showing that the prior art taught away from the invention, he failed to do so. Many of the cited prior art references disclosed the advantages of the claimed ranges, and one, Wukusick, expressly taught that adding rhenium improves high-temperature strength.

Thus, the Federal Circuit found substantial evidence to support the Board’s finding that the claimed ranges are encompassed by Shah, that Peterson failed to show unexpected results, and that the prior art did not teach away from the claimed invention.