In In re Rambus Inc., No. 11-1247 (Fed. Cir. Aug. 15, 2012), the Federal Circuit affirmed the Board's decision in a reexamination that claim 18 of U.S. Patent No. 6,034,918 ("the '918 patent") was invalid as anticipated.
The '918 patent, titled "Method of Operating a Memory Having a Variable Data Output Length and Programmable Register," derives from U.S. Patent Application No. 07/510,898 ("the '898 application"). The '918 patent is directed to synchronous memory devices, where the devices achieve greater control and faster data storage and retrieval over the prior asynchronous memory devices. The '918 patent describes a method whereby synchronous memory devices output only a specified amount of data in response to a request. Claim 18 of the '918 patent claims a method of operation of a synchronous "memory device."
In 2005, Rambus Inc. ("Rambus") sued Hynix Semiconductor, Inc. ("Hynix"), Micron Technology, Inc. ("Micron"), and others for patent infringement, asserting multiple patents from the '898 application family. The district court construed the term "memory device" and found that Hynix infringed certain claims of the '918 patent. Hynix then initiated ex parte reexamination proceedings in the PTO. The PTO examiner found that the "memory device" limitation of claim 18 of the '918 patent read on a prior art publication, the iAPX 432 Interconnect Architecture Reference Manual, published by Intel Corp. in 1982 ("iAPX Manual"), which disclosed a "memory module." Thus, the PTO examiner found claim 18 invalid as anticipated.
The Board affirmed, framing the central dispute as "whether the claimed term 'device' is limited to a single 'chip' embodiment or also embraces a 'memory stick' [or transceiver device] embodiment as disclosed in the '918 patent." Slip op. at 6 (alteration in original) (citation omitted). Accordingly, the Board's analysis focused on the specification disclosing that, "[i]n general, each teaching of this invention which refers to a memory device can be practiced using a transceiver device and one or more memory devices." Id. (alteration in original) (citation omitted).
The Board agreed with the district court that "claim 18 does not recite a chip device and the patentee must live with the broader memory device term recited." Id. The Board also agreed that a memory device as used in the '918 patent cannot be defined by the exact number of chips it is composed of—but that number does not have to be restricted to one. The Board also noted that the memory stick embodiment does not appear to have a CPU or microprocessor. The Board then cited to Rambus's expert declaration that the memory control unit ("MCU") in the iAPX Manual merely receives and translates instructions from the Bus Interface Unit ("BIU"), and concluded that the MCU is not a microprocessor or CPU. The Board therefore equated the iAPX "memory module" with the "memory device" of the '918 patent and affirmed the examiner's rejection of claim 18 as anticipated by the iAPX Manual. Rambus appealed.
"To the extent Rambus wanted to limit the memory device to a single chip component, it could have expressly done so. It did not, and this court will not do so here." Slip op. at 9.
On appeal, the Federal Circuit first considered Rambus's challenges to the Board's construction of "memory device." The Board construed "memory device" to mean a "device that allows for the electronic storage and retrieval of information." Id. at 7 (alteration in original) (citation omitted). Rambus argued that the Board erred because "memory device" has two additional limitations: (1) that it is a single chip component; and (2) it does not have a memory controller. To support its argument that "memory device" was a single chip component, Rambus pointed to the specification, expert testimony, the prosecution history, and related patents. The Court, however, found that none of these limit "memory device" to a single chip configuration.
With regard to the specification, the Court conceded that, while Rambus cited certain examples in the '918 patent where the memory device indeed had a single chip configuration, nothing limited the invention to a single chip configuration. As the Court explained, if Rambus "wanted to limit the memory device to a single chip component, it could have expressly done so. It did not, and this court will not do so here." Id. at 9. Regarding expert testimony, Rambus argued that in prior litigation over other related patents in the '898 application family, Rambus and Hynix jointly stipulated, and the district court agreed, that "memory device" meant an integrated circuit device limited to a single chip, and pointed to expert testimony supporting this construction. On the other hand, the Board determined that the '918 patent was drawn to broader subject matter than other patents in the '898 application family, and the plain meaning of "memory device" was not limited to a single chip configuration. The Court agreed with the Board, finding the expert testimony unpersuasive. And finally, the Court disagreed with Rambus that it limited the invention to a single chip configuration as a distinguishing feature over the prior art. The Court instead was persuaded by the Board that, in other patents in the '898 application family, Rambus specifically and expressly claimed the single chip configuration, and its failure to do so here meant that "memory device" was not limited to the single chip configuration.
The Federal Circuit next considered whether the proper construction of "memory device" meant that it did not have a memory controller. Rambus argued that the invention's goal was speed and efficiency, and to achieve those goals, the memory device must be as simple as possible, thereby excluding control functionality. Although the Court agreed that speed and efficiency were goals of the invention, it explained that this did not mean that the memory device lacked all control functionality. Pointing to the language of claim 18, the Court concluded that, "[i]n fact, the claim expressly calls for the memory device to provide the control functionality" of managing data. Id. at 14. Thus, the Court did not limit the construction of "memory device" to exclude control functionality.
Next, the Court considered whether substantial evidence existed to support the finding that claim 18 is anticipated by the prior art iAPX Manual. Accepting Rambus's characterization of the iAPX Manual's "memory module," the Court concluded that claim 18 is anticipated by this prior art. By not restricting a "memory device" to a single chip or otherwise restricting the necessary interface control logic function within the claims, the Court determined that there was simply no principled way to distinguish the iAPX Manual's "memory module," which contained several chips and a controller that provided the logic for those chips to function, from the '918 patent's "memory device." Accordingly, the Court affirmed the Board's decision.
Judges: Rader, Linn (author), Dyk
[Appealed from Board]
This article previously appeared in Last Month at the Federal Circuit, September, 2012.
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