“in asserting patent invalidity as a defense to an infringement action, an alleged infringer must contend with §282 of the Patent Act of 1952 (Act), under which “[a] patent shall be presumed valid” and “[t]he burden of establishing invalidity . . . shall rest on the party asserting” it. Since 1984, the Federal Circuit has read §282 to require a defendant seeking to overcome the presumption to persuade the factfinder of its invalidity defense by clear and convincing evidence”.Bearing in mind that “Section 282 requires an invalidity defense to be proved by clearand convincing evidence”, “the Court rejects Microsoft’s contention that a defendant need only persuade the jury of a patent invalidity defense by a preponderance of the evidence”.
The justices also reject “Microsoft’s argument that a preponderance standard must at least apply where the evidence before the factfinder was not before the PTO during the examination process”
Reference is also made to the fact that “during the nearly 30 years that the Federal Circuit has interpreted §282 as the Court does today, Congress has often amended §282 and other patent laws, but apparently has never considered any proposal to lower the standard of proof. Indeed, Congress has left the Federal Circuit’s interpretation in place despite ongoing criticism, both from within the Federal Government and without”.
Microsoft Corp. must therefore pay a $290 million to i4i.
US Supreme Court opinion here