Microsoft Corp. v. i4i Ltd. Partnership

Under § 282 of the Patent Act of 1952, “[a] patent shall be presumed valid” and “[t]he burden of establishing invalidity of a patent or any claim thereof shall rest on the party asserting such invalidity.” 35 U. S. C. §282. We consider whether § 282 requires an invalidity defense to be proved by clear and convincing evidence. We hold that it does.

I

A

Pursuant to its authority under the Patent Clause, U. S. Const., Art. I, §8, cl. 8, Congress has charged the United States Patent and Trademark Office (PTO) with the task of examining patent applications, 35 U. S. C. § 2(a)(1), and issu*96ing patents…