Especially considering that appeal focused solely on claim construction, it does seem peculiar that both parties forewent a Markman hearing, thus open-ending that crucial aspect of litigation.

This case primarily involves issues of claim construction. In construing patent claims we follow the methodology set forth in our recent en banc decision in Phillips. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). 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 control 4. [4 Of course, if the district court has not yet construed the claims, testifying experts must make clear the claim constructions that they have assumed in their testimony. See, e.g., Frank’s Casing Crew v. PMR Techs., LTD., 292 F.3d 1363 (Fed. Cir. 2002) (rejecting an expert’s conclusion that a claim limitation was not satisfied because it was based on an incorrect claim construction).]

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.