Although the jury found the claims valid, and the Fed. Cir. affirmed, this decision, which found that the claims were not insolubly ambiguous, was revisited by the Fed. Cir. While there are pages on issue preclusion, in the end, the Fed. Cir. took the appeal and reversed its original position. Here there were four possible methods to measure the parameter “stretch hardening” of the claimed polymer, and the specification did not identify which one was used. Following Teva, in which three methods of measuring molecular weight led to the Supreme Court’s imposition of the “reasonable certainty” standard for determining if a claim satisfied s.112, the Fed. Cir. had little choice but to invalidate the claims that recited this parameter. I have always resisted the mantra that would require lots of definitions of claim elements, but the writing is on the wall, and this new “easy-to-use” mode of claim invalidation will only gain momentum.

Dow v Nova