Jury Testimony on Claim Construction Improper

In Cytologix Corp. v. Ventana Medical Systems, Inc. (Fed. Cir.; Sepetmebr 21, 2005), the court conclyuded that CytoLogix failed to present substantial evidence of infringement of claim 13 of the ’693 patent because it did not conduct a structural analysis of means-plus-function limitations in that claim:

The "temperature controller" limitation of claim 13 is a means-plus-function limitation as defined by 35 U.S.C. § 112, ¶ 6. Infringement of a means-plus-function limitation "requires that the relevant structure in the accused device . . . be identical or equivalent to the corresponding structure in the specification." Odetics, Inc. v. Storage Tech. Corp., 185 F.3d 1259, 1267 (Fed. Cir. 1999). To establish infringement under § 112, ¶ 6, it is insufficient for the patent holder to present testimony "based only on a functional, not a structural, analysis." Alpex Computer Corp. v. Nintendo Co., 102 F.3d 1214, 1222 (Fed. Cir. 1996). Here, CytoLogix failed to identify the structure in the specification that is the "temperature controller means" and compare it to the structure of the accused device. Accordingly, because CytoLogix failed to present substantial evidence of infringement of claim 13 of the ’693 patent, the jury verdict of infringement of claim 13 must be reversed.

Instead of offering such structural analysis, the parties agreed to have there experts testify before the jury on claim constrction:

We note that in this case the parties agreed, contrary to the district court’s wishes, not to have a Markman hearing, and that the claims were not construed until the close of evidence. This was not erroneous since we have held that the district court has considerable latitude in determining when to resolve issues of claim construction. See Jack Guttman, Inc. v. Kopykake Enters., Inc., 302 F.3d 1352, 1361 (Fed. Cir. 2002) ("District courts may engage in a rolling claim construction, in which the court revisits and alters its interpretation of the claim terms as its understanding of the technology evolves."). However, by agreement the parties also presented expert witnesses who testified before the jury regarding claim construction, and counsel argued conflicting claim constructions to the jury. This was improper, and the district court should have refused to allow such testimony despite the agreement of the parties.

The risk of confusing the jury is high when experts opine on claim construction before the jury even when, as here, the district court makes it clear to the jury that the district court’s claim constructions controlcase the parties agreed, contrary to the district court’s wishes, not to have a Markman hearing, and that the claims were not construed until the close of evidence.

Although in this case there is no ground for reversal since there was no objection to the expert testimony as to claim construction, it appears that the conflicting expert views as to claim construction created confusion and may have led to a verdict of infringement with respect to the asserted claims of the ’061 patent that was not supported by substantial evidence under the district court’s claim construction. We nonetheless conclude that the verdict should be sustained as to these claims because, although the district court’s claim construction was in error, the evidence requires a verdict of infringement under the correct claim construction [of the other claims].