A Blog About Intellectual Property Litigation and the District of Delaware


Entries for tag: daubert

Yesterday, Judge Andrews excluded testimony by an expert that improperly advanced a "practicing the prior art" defense. It has been firmly established that "practicing the prior art" is not a defense to literal infringement, and thus is not a proper subject for expert testimony. It is acceptable, however, for litigants to argue that if a patentee interprets a claim broadly for infringement purposes, the claim will read on the prior art ("that which infringes, if later, would anticipate, if earlier," the corollary of the proverbial "nose of wax" principle that prohibits parties from taking one view of claim scope for infringement purposes and another for invalidity).

[UPDATE: Apparently not! This opinion was reversed on a motion for reconsideration; further update below]

Judge Connolly today struck portions of an expert report where the expert opined that the accused product did not infringe because it included extra components in addition to what was claimed in a means-plus-function claim element.

According to the Court, this is contrary to the well-established principle that additional structure does not preclude infringement of an MPF claim element, if the required structure is also there.

[UPDATE: As the Court recognized on reconsideration, that was not what was happening here. Instead, the expert was pointing out that the opposing party's expert had failed to identify the a structure that performed the function, not that the …