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PTAB Denies Petition for Inter Partes Review

In IPR2012-00041, the Patent Trial and Appeals Board (“PTAB”) (A.P.J.s Medley, Blankenship and Bisk) issued an order in Synopsys, Inc. (“Petitioner”) v. Mentor Graphics Corporation (“Patent Owner”) denying Synopsys’ petition. In its petition, Synopsys sought review of U.S. Patent No. 6,947,882 relating to systems for emulating integrated circuit designs. Synopsys argued that claims 1-14, 17-20 were anticipated and/or rendered obvious based on four prior art U.S. patents, one of which was incorporated by reference into one of the other three patents. Notably, the ‘882 patent is involved in concurrent litigation with a Markman hearing set for July 23, 2013 and a jury trial set for June 16, 2014.

In declining to institute an inter partes review of any of the challenged claims on any of the proposed grounds, the Board agreed with the Petitioner that the claims terms should be given their ordinary meaning, except for a single claim limitation. The exception, however, relates to the claim term “wherein clocking of the second time multiplexed interconnection is independent of clocking of the first time multiplexed interconnection.” About this term, the Board stated that the Petitioner implicitly asserts that the independent clock signal limitation encompasses asynchronous clock signals originating from a single clock. As explained below, however, the Board’s construction of this term in a manner different that the Petitioner’s implied definition turned out to be fatal to Synopsys’ petition for inter partes review.

In its preliminary response, the Patent Owner explained that asynchronous clocks are not necessarily independent. In the context of the ‘882 specification, the independent clock signal limitation does not encompass asynchronous signals created by a single clock. In agreeing with the Patent Owner, the Board explained that “[t]he plain and ordinary meaning of ‘independent’ is ‘not affiliated with a larger controlling unit,’ Thus, the plain and ordinary meaning of the independent clock signal limitation requires that the two independent clock signals are not affiliated with one controlling clock and instead the signals originate from separate clocks.” The Board also determined that nothing in the specification indicated that “independent” should be interpreted in another way. To the contrary, Figure 5 of the ‘882 patent showed clocks that were independent of one another.

Critically, the prior art relied upon by the petitioner disclosed only the use of asynchronous clocks. The Board did not take issue with this assertion, but found that asynchronous clock signals does not necessarily require that they are independent. That is, the disclosed signals could be from a single clock, but not synchronized. The other relied upon prior art disclosed the use of different clocks, but does not disclose that the different clock signals are used simultaneously, or by the same logic device, or to clock different multiplexed interconnects. Even if these clock signals were independent, the Board pointed out that anticipation requires more than simply disclosing every element of the challenged claims, it also requires that the anticipatory reference disclose the elements arranged in the claims.

Petitioner next argued that if the prior art did not anticipate, then the prior art would have rendered the claims obvious. The Board explained that the petitioner’s conclusory statements, without more detail, failed to point out with the requisite specificity why the asserted claims would have been obvious in light of the cited prior art.


This decision demonstrates that, despite the high percent of petitions granted to date, the grant of a petition for inter partes review is not automatic and that the higher standard of showing that there is a reasonable likelihood that at least one of the challenged claims is unpatentable should not be taken lightly. Petitioner would be well advised to submit prior art that discloses the claimed features that cover reasonable interpretations of the claim terms or risk having the Board construe the terms in a way that distinguishes them over the cited prior art. Moreover, any obviousness arguments should clearly explain the basis for asserting that the claims would have been obvious should explicitly set forth the reasons a person of ordinary skill in the art would be motivated to combine the prior art to arrive at the claimed invention.
Synopsys, Inc. v. Mentor Graphics Corporation, Case IPR2012-00041 (J. Bisk) (February 22, 2013), Paper 16.

The authors of are patent trial lawyers at Jeffer Mangels Butler & Mitchell LLP. The authors represent inventors, patent owners and technology companies in patent licensing and litigation in U.S. District Courts and in the United States Patent and Trademark Office, including numerous IPRs currently pending before the PTAB. Whether pursuing patent violations or defending infringement claims, we are aggressive and effective advocates for our clients. For more information contact Greg Cordrey at 949.623.7236 or