Court Finds Dow Claims Clearly Indefinite

In Dow Chemical Co. v. Nova Chemicals Corp., the Federal Circuit held claims reciting a limitation that could be calculated in several ways indefinite where the patent claims, specification, and prosecution history failed to indicate which method should be used. For those wondering whether the “reasonable certainty” standard set forth in the Supreme Court’s Nautilus decision will have any real-world impact, this case shows that it can, since the Federal Circuit previously upheld the same claims under the “insolubly ambiguous” standard.

The Dow Patent Claims At Issue

Claim 6 of U.S. Patent No. 5,847,053 is representative of the claims challenged on indefiniteness grounds:

6. An ethylene polymer composition comprising