by Dennis Crouch
Koss Corporation v. Bose Corporation, 22-2090 (Fed. Cir. July 19, 2024)
In its final written decisions, the PTAB found a number of Koss patent claims invalid and Koss appealed to the Federal Circuit. In the end, though the appellate panel found the appeals moot because all the claims had been invalidated in parallel district court litigation. Although the prior litigation involved a different party (Plantronics), Bose was able to take advantage of that invalidation decision under the doctrine of non-mutual collateral estoppel established by the Supreme Court in Blonder-Tongue Lab'ys, Inc. v. Univ. of Ill. Found., 402 U.S. 313 (1971).
Koss attempted a clever pleading trick