Roland Corporation v. inMusic Brands, Inc., decided March 27, 2025

This Federal Circuit opinion documents an appeal and cross-appeal in a patent infringement lawsuit between Roland Corporation and inMusic Brands concerning electronic drums and cymbals. Roland initially sued inMusic for infringing eight patents. The district court granted partial summary judgment of non-infringement, and a jury subsequently found the remaining patents infringed. Both parties appealed aspects of the district court's rulings, including claim construction, expert testimony, infringement findings, validity, damages, equitable estoppel, and prejudgment interest. The Federal Circuit affirmed some findings, reversed others, vacated the damages award, and remanded for a new trial on damages, finding errors in the calculation of both lost profits and reasonable royalties, while also addressing the denial of prejudgment interest.