After concluding that the district court impermissibly narrowed the asserted patent claims, the U.S. Court of Appeals for the Federal Circuit overturned a jury verdict invalidating those claims and ordered a new trial to consider evidence of commercial success. ArcelorMittal France et al. v. AK Steel Corp. et al., Case No. 11-1638 (Fed. Cir., Nov. 30, 2012) (Dyk, J.) (Wallach, J., dissenting-in-part). 

In January 2010, ArcelorMittal sued AK Steel in district court alleging that AK Steel’s aluminum-coated steel sheet products infringed certain claims of ArcelorMittal’s boron steel sheet patent.  The district court issued a claim construction order largely favoring AK Steel’s position.  In relevant part, the district court construed the term “a hot-rolled steel sheet coated with an aluminum or aluminum alloy coating” to include only steel sheets that had been reduced to a final thickness by hot-rolling.  This construction excluded steel that was first hot-rolled and then cold-rolled to its final thickness.

Under this construction, the AK Steel accused products did not literally infringe, so the district court prohibited ArcelorMittal from asserting literal infringement.  The matter proceeded to trial on the issue of infringement under the doctrine of equivalents.  A jury returned a verdict finding that AK Steel did not infringe ArcelorMittal’s patent and that the asserted claims were both obvious and anticipated.  The district court entered final judgment for AK Steel after denying ArcelorMittal’s motion for judgment as a matter of law on the invalidity issues and for a new trial on infringement.  ArcelorMittal appealed.

In addressing the claim construction issue, the Federal Circuit explained that the district court improperly relied on extrinsic evidence to construe “a hot-rolled steel sheet coated with an aluminum or aluminum alloy coating” where the specification unambiguously contemplated steel that was first hot-rolled and the cold-rolled to its final thickness.  Because the claim used the term “comprising,” the Federal Circuit explained that additional, non-claimed steps disclosed in the specification fall within the claim scope and cannot be excluded.  Under the new construction, it is at least possible that AK Steel’s products may literally infringe.

The Federal Circuit thus reversed the district court, concluding that a new trial was warranted because the error in the district court’s claim construction prevented the jury from properly considering both a disclosed embodiment of the invention as well as ArcelorMittal’s evidence of commercial success.  The Federal Circuit remanded the case for a new trial limited to the issue of whether under the correct claim construction, AK Steel literally infringes the asserted claims and whether the claims are non-obvious in light of any evidence of commercial success of hot-rolled steel (that is also cold-rolled) and that has the required nexus with the asserted patent claims. 

The Federal Circuit also reversed the lower court’s finding of anticipation.  The prior art reference used to anticipate the claims did not expressly disclose coating with aluminum or aluminum alloy.  Rather, it disclosed paint coatings, not metal, and there was insufficient evidence that one of ordinary skill would understand that the variety of paint coatings disclosed could be replaced with aluminum or aluminum alloy.

However, the Federal Circuit did affirm the district court’s finding of a prima facie obviousness, based on substantial evidence that the jury could have found that the primary reference disclosed a pre-coating and the secondary reference disclosed using aluminum in an analogous art.  Whether a reference discloses a particular element and whether a reference is analogous art are factual issues for a jury.

The Federal Circuit also found that the district court’s incorrect claim construction precluded the jury from properly evaluating ArcelorMittal’s evidence of commercial success of its cold-rolled products.  The Federal Circuit explained that the commercial success of an embodiment with additional unclaimed features must be considered when evaluating obviousness, provided that the embodiment’s success has a sufficient nexus to the claimed features.  Moreover, the Federal Circuit noted that the prima facieobviousness case here was not so strong that it would necessarily withstand ArcelorMittal’s commercial success evidence.

Practice Note:  The Federal Circuit’s findings on commercial success demonstrate that a broader range of products may be used as evidence to demonstrate non-obviousness.  Products may include additional features can form the basis for a commercial success argument as long as the product's commercial success is based upon the claimed features.