Sonos Fends Off Nine-Year-Old Patent Lawsuit at Federal Circuit

A patent owner that corrected its patents midway through a nine-year infringement battle against Sonos Inc. forfeited its right to gain a litigation advantage based on those changes, the Federal Circuit ruled.

The Patent Trial and Appeal Board invalidated two Implicit LLC patents based on an earlier filed patent describing a way to synchronize media content. Implicit later updated its US Patent Nos. 7,391,791 and 8,942,252 in a way that buttressed its arguments for an early priority date.

Judge Tiffany P. Cunningham said Implicit’s arguments lost the right to raise the arguments and that its strategy “raised concerns of sandbagging,” ...