Having vacated a district court’s finding of infringement by Hynix Semiconductor, Inc. in Hynix v. Rambus, (see IP Update, Vol. 14, No. 6), the U.S. Court of Appeals for the Federal Circuit affirmed a decision of the U.S. Patent and Trademark Office Board of Patent Appeals and Interferences (the Board) in a reexamination proceeding, finding one of the patents asserted in the prior Hynix case invalid as anticipated based upon the construction of a disputed claim term.  In re Rambus, Case No. 11-1247 (Fed. Cir., Aug. 15, 2012) (Linn, J.).

During ex parte reexamination of the asserted claim (of the then expired Rambus patent), the examiner applied what he believed to be the appropriate construction to the term “memory device” to mean a “device that allows for the electronic storage and retrieval of information.”  Relying on this construction, the examiner rejected the claim as anticipated by a prior art manual published by Intel Corp. in 1982.  The manual disclosed a “memory module” having an array of chips and a memory control unit (MCU).  The Board affirmed the examiner’s rejection based on this construction of “memory device” in the claim. Rambus appealed.

Rambus argued at the Federal Circuit that the stated goals of the invention required a single chip memory device without a memory controller or control functions, citing to portions of the specification describing a “memory device” in such a way.  The Federal Circuit rejected this argument, finding that the use of the term “memory device” in the specification to describe embodiments of single-chip devices does not necessarily restrict the invention to single-chip memory devices.  The Court explained that language in the specification describing “only preferred embodiments” does not exclude other embodiments that are also described in the specification.  The Federal Circuit also refused to limit the memory device term to a single chip device when Rambus could have expressly done so itself during prosecution of the application for the patent, but chose not to. 

According to the Federal Circuit, the Board’s construction is consistent with the use of the term in other patents in the same family where Rambus used the term “memory device” in the independent claim and included a dependent claim covering memory devices formed on a single chip component.  Quoting from Omega Eng’g, Inc., the Court noted that “unless otherwise compelled … the same claim term in the same patent or related patents carries the same construed meaning.” 

The Court also found that nothing in the claim or specification limits the control functionality of the memory device and explained that “excluding more complex controllers does not eliminate all control functionality.”  The Court distinguished its prior decision in Lisle by noting that the “general speed and efficiency goals” of Rambus’s invention do not require a different construction of “memory device” that excludes all control functions including the claimed functions of receiving and outputting data. 

The Court concluded that “[b]y not restricting a memory device to a single chip or otherwise restricting the necessary interface control logic function within the claims, there is simply no principled way to distinguish” the memory module disclosed in the prior art reference manual from the memory device in Rambus’s patent.