Patent practitioners are probably well familiar with circumstances in which prosecution history estoppel can limit the scope of a U.S. utility patent’s claims.  Examples include claim amendments and statements made by the applicant during prosecution in papers filed with the U.S. Patent and Trademark Office (USPTO).  Less common are scenarios in which prosecution history estoppel may limit a U.S. design patent’s claims.  The Federal Circuit’s recent decision in Advantek Marketing, Inc. v. Shanghai Walk-Long Tools Co.provides one scenario where prosecution history estoppel for a design patent was a key issue in claim interpretation.

During prosecution of Advantek’s U.S. Design Patent No. D715,006 (the D’006 patent), the USPTO required election between (1) a portable animal kennel withouta cover, and (2) a portable animal kennel with a cover.  The applicants elected embodiment (1).

After issuance of the D’006 patent, Advantek sued Walk-Long in the U.S. District for the Central District of California.  The district court held that prosecution history estoppel bars infringement by Walk-Long since Walk-Long’s kennel includes a cover and the applicants’ election surrendered kennels with a cover from the D’006 patent’s claim scope.  The district court was not persuaded by Advantek’s argument that Walk-Long’s kennel falls within the “skeletal structure design” of the elected kennel, regardless of whether or not the kennel has a cover.  The district court was also not persuaded by Advantek’s argument that prosecution history estoppel should not apply because the applicants’ election did not narrow the claim’s scope but instead was broadening since the elected embodiment covers the kennel’s “skeletal structure design” whether or not it is used with or without other parts.  In reaching its decision the district court relied upon the 2014 Federal Circuit case Pacific Coast Marine Windshields Ltd. v. Malibu Boats, LLC, which “held that prosecution history estoppel in a design patent case depends on:  ‘(1) whether there was a surrender; (2) whether it was for reasons of patentability; and (3) whether the accused design is within the scope of the surrender.’”

The Federal Circuit in Advantek disagreed with the district court.  The court held that whether or not Advantek actually surrendered claim scope during prosecution, Walk-Long’s product was outside the scope of the possible surrender because “[a] competitor who sells a kennel embodying Advantek’s patented structural design infringes the D’006 patent, regardless of extra features, such as a cover, that the competitor might add to its kennel.”

This case highlights important post-issuance consequences of an election made during prosecution of a design patent application as well as providing a reminder to carefully consider the value of filing divisional patent application(s) to cover any or all unelected inventions.