PTAB rules prohibit raising new arguments in a reply brief, but
it can be difficult to distinguish between an improper reply
argument and a proper rebuttal. In Idemitsu Kosan Co. v. SFC Co., No.
2016-2721 (Fed. Cir. Sept. 15, 2017), the Federal Circuit
determined that the IPR petitioner properly made a rebuttal
argument—not a belated, new argument—in its reply
brief, and the court affirmed the PTAB's decision canceling the
challenged claims for obviousness.
Petitioner SFC Co. filed an IPR petition challenging claims of
Patent Owner Idemitsu Kosan Co.'s patent, entitled
"Organic Electroluminescence Device and Organic Light Emitting
Medium." The challenged claims recite an electroluminescence
device including a pair of electrodes, with an organic light
emitting layer between the electrodes. The organic light emitting
layer includes: (A) an arylamine compound of a particular formula;
and (B) at least one compound selected from particular anthracene
derivatives and
