Blonder Tongue v. University of Illinois Found. - 402 U.S. 313 (1971)
U.S. Supreme Court
Blonder Tongue v. University of Illinois Found., 402 U.S. 313 (1971)
Blonder Tongue Laboratories, Inc. v.
University of Illinois Foundation
Argued January 14, 1971
Decided May 3, 1971
402 U.S. 313
This Court's holding in Triplett v. Lowell, 297 U. S. 638, that a determination of patent invalidity is not res judicata against the patentee in subsequent litigation against a different defendant overruled to the extent that it forecloses an estoppel plea by one facing a charge of infringement of a patent that has once been declared invalid, and in this infringement suit, where, because of Triplett, petitioner did not plead estoppel and the patentee had no opportunity to challenge the appropriateness of such a plea, the parties should be allowed to amend their pleadings and introduce evidence on the estoppel issue. Pp. 402 U. S. 317-350.
422 F.2d 769, vacated and remanded.
WHITE, J., delivered the opinion for a unanimous Court.