Patent Infringement Patent ValidityA patent owner recently brought an infringement lawsuit against alleged infringers in the U.S. District Court for the Eastern District of Virginia. The claim was direct infringement of its patent for a specific method of authenticating mobile station users to access private data by sending text messages to a private server. Defendants, who were banking institutions, were sued collectively for patent infringement. They moved for summary judgment. They argued whether plaintiff’s proffered evidence on the doctrine of equivalents was admissible, based on the sole evidence that relied on a statement in the Defendants’ expert report.

The statement by the Defendants’ expert, according to the Plaintiff, was sufficient to establish infringement under the doctrine of equivalents because it was substantial evidence that demonstrated equivalence under the interchangeability test, which requires that “the knowledge of a skilled artisan … would contemplate the interchange as a design choice.” Defendants argued that, even if admissible, the statement by the Defendants’ expert was insufficient for a reasonable jury to find infringement and that the statement by the expert wasn’t admissible.

District Judge T.S. Ellis, III noted in his decision that that Plaintiff’s argument under the doctrine of equivalents was based solely on the fact that one Federal Circuit opinion used the phrase “design choice” when discussing the insubstantiality test and that the defendants’ expert also used the phrase “design choice” in his report on invalidity. The Plaintiff’s proffered doctrine of equivalents evidence fell way short of the Federal Circuit’s evidentiary standard that “a patentee … provide particularized testimony and linking argument as to the ‘insubstantiality of the differences’ between the claimed invention and the accused device or process … to support a finding of infringement under the doctrine of equivalents.” Judge Ellis held that the Defendants’ expert’s statement wasn’t particularized and provided no linking argument on the insubstantiality of the differences between the claimed and accused systems. In particular, the expert’s statement did not contain information on how or why the differences between the claimed and accused methods were insubstantial.

The Defendants’ expert’s statement on the separate issue of invalidity was far less probative of infringement under the doctrine of equivalents than a plaintiff’s own literal infringement evidence. The Defendants’ expert’s conclusory assertion was, the order of the authenticity checking steps was a “design choice” didn’t cut it. As a result, the judge held that the plaintiff’s evidence on the doctrine of equivalents, even if admissible, was insufficient to support a finding of infringement under the doctrine of equivalents.

Judge Ellis held that, even assuming the Defendants’ expert’s statement would be sufficient evidence for a reasonable jury to find infringement under the doctrine of equivalents, they were nonetheless entitled to summary judgment because the Plaintiff couldn’t produce admissible evidence to show infringement under the doctrine of equivalents—an issue on which Plaintiff carried the burden of proof.

Defendants solicited their expert report in preparation for a potential invalidity defense and had the option to not use the expert. In that case, the issue was whether the Plaintiff could successfully offer the Defendants’ expert’s statement into evidence. The court ruled that the expert’s report wasn’t admissible under an exception to the hearsay rule. Even though there’s no Federal Circuit authority on point, Judge Ellis explained that the Third Circuit squarely addressed and rejected the contention that an opponent’s expert report is admissible under Rule 801(d)(2).

The Third Circuit concluded that, “since an expert witness is not subject to the control of the party opponent with respect to consultation and testimony he or she is hired to give, the expert witness cannot be deemed an agent.” An expert report therefore is not admissible under Rule 801(d)(2) absent a showing that the expert was acting as the party’s agent, employee, or was specifically authorized to make a statement on that subject—not the case in in this action.

The Defendant was entitled to summary judgment. The Plaintiff’s allegation of infringement under the doctrine of equivalents failed because it didn’t produce any admissible evidence to create a triable issue of fact on infringement under the doctrine of equivalents.

By: Kurt R. Mattson, LLM, J.D.
20+ years of legal experience