In re Rambus, Inc.

Addressing a finding of anticipation by the United States Patent and Trademark Office (PTO) Patent Trial and Appeal Board (PTAB) in aninter partes review, the U.S. Court of Appeals for the Federal Circuit reversed the PTAB’s decision, finding that a value cannot “represent” an “amount of time” if there are additional factors, wholly unrepresented by that value, that necessarily impact, or represent, the “amount of time.”  In re Rambus, Inc., Case No. 13-1192 (Fed. Cir., June 4, 2014) (Reyna, J.).

Micron Technology (Micron) petitioned for inter partes review (IPR) at the PTO of a patent owned by Rambus.  The patent was directed to a method and system for improving the efficiency of computer memory.  The parties disputed before the PTAB whether a prior art patent disclosed “a value that is representative of an amount of time to transpire after which the memory device outputs the first amount of data.”  The examiner found the limitation lacking in the art.  The PTAB disagreed and found the prior art anticipatory.  Rambus appealed.

After oral argument at the Federal Circuit, but prior to the Court’s ruling, Micron withdrew from the case.  Given Rambus’ right to appeal the PTAB’s rejection of its patent claims irrespective of Micron’s participation in the appeal, the Federal Circuit found that, despite Micron’s withdrawal, a live controversy regarding the patentability of Rambus’s claims remained before the Court for resolution.

The claims of the patent being reexamined were expired.  As a result, the Federal Circuit applied the claim construction principles outlined in Phillips v. AWH Corp., (IP Update, Vol. 8, No. 12), instead of the broadest reasonable interpretation that is typically used in IPRs. Under this standard, the Court found that the PTAB’s conclusion was not supported by substantial evidence.

The Federal Circuit rejected Micron’s argument at the PTAB that the prior art patent disclosed a value that is representative of an amount of time to transpire after which the memory device outputs the first amount of data.  The figures of the prior art patent showed a parameter that could be set that resulted in multiplexing, which, according to Micron and the PTAB, caused a delay of known value before data could be transferred over the multiplexed line.

Rambus argued that the figures were simplified, hypothetical illustrations of how the invention of the prior art patent worked in theory and not schematics of how the patented invention actually worked.  Rambus pointed out that, in practice, other factors impact the timing of the data transfer that have nothing to do with the parameter identified by Micron and the PTAB.  As a result, when the prior art invention is practiced there is no known delay time; rather, it has an indefinite delay time.

The Federal Circuit agreed with Rambus, finding that a value cannot represent an amount of time if there are additional factors that impact the amount of time.