Supreme Court Affirms Clear and Convincing Standard for Patent Invalidity Defenses
By Samantha Kuhn – Edited by Esther Kang
Microsoft Corp. v. i4i Ltd. P’ship, No. 10–290 (U.S. June 9, 2011)
Slip Opinion (via supremecourt.gov)
On June 9, the Supreme Court affirmed a district court’s jury instructions requiring that the evidence of patent invalidity be “clear and convincing” for the invalidity defense against infringement to be successful.
In a unanimous decision, the Supreme Court held that the presumption of validity in Section 282 of the Patent Act requires that a defendant must present “clear and convincing” evidence that a patent is invalid in order to succeed on an invalidity defense. The main issue in the case was whether a lesser standard should be applied to evidence that had not been previously presented to the PTO during examination. The Court rejected Microsoft’s proposal of a “preponderance of the evidence” standard in such cases.
PatentlyO provides a summary of the case and concurring opinions. IP Watchdog gives a summary of the case and opines about its implications on patent law. The Digest previously covered both the district court’s decision and the oral arguments before the Supreme Court.








