The election of an invention in response to an ambiguous restriction requirement from the PTO cannot form the basis for prosecution estoppel or justify a court’s narrowing of a broadly drafted claim.

Plantronics, Inc. v. Aliph, Inc. and Aliphcom, Inc., No. 2012-1355 (Fed. Cir. July 31, 2013).

When patentee first applied to patent an earphone headset for cellular phone devices, the PTO found four patentably distinct species of inventions and required patentee to make an election among them. Patentee did so, but contended that one of its claims was generic and covered all of the disclosed species. Eventually, the PTO issued the patent.

Patentee later sued defendant for infringement, and defendant contended that prosecution estoppel barred patentee from claiming a structure any broader for the patent than what was specifically presented in the claims it had elected when required to do so by the PTO. The defendant argued that the claims were limited to elongated structures and the district court agreed, putting a narrowing limitation on the patent’s structural claims and entering a finding of noninfringement as a result of this construction. 

The Federal Circuit reversed and remanded. The PTO had given no reason why the patent represented four separate species, and did not clearly demarcate what the actual differences among them were (i.e., whether they differed in structure or otherwise). The court noted that when a patentee unequivocally and unambiguously disavows a certain meaning to obtain a patent, the doctrine of prosecution history disclaimer narrows the meaning of the claim consistent with the scope of the claim surrendered, but that plaintiff’s election of species did not amount to such a surrender of claim scope. As a result, there was no basis for the district court to narrow the broadly drafted, generic claims at issue during construction to require elongated structures, and no grounds upon which the alleged infringer could assert prosecution estoppel.

The Federal Circuit also reversed the district court’s finding on summary judgment that the patentee?s claims were obvious based on a skilled artisan’s motivation to combine certain prior art references by “common sense.” The Federal Circuit emphasized that such findings must contain explicit and clear reasoning providing some rational underpinning why common sense compels a finding of obviousness. Because the commercial success of the product copied by defendant and the prior failure of attempts to combine prior art elements were not considered by the lower court, the Federal Circuit reversed, holding that genuine issues of material fact existed as to whether it would be “common sense” to combine the prior art as suggested.

A copy of the opinion can be found here