The Risks of Inconsistent Arguments in Parallel Proceedings

Scott Daniels | May 3, 2012

A patentee, who is simultaneously pursuing an infringement in District Court and defending its patent in a reexamination proceeding at the PTO, often faces the temptation to construe its claims broadly in court but narrowly at the PTO.  The risks of yielding to that temptation are illustrated in Judge Susan Illston’s claim construction decision Tuesday in Kilopass Technology v. Sidense (2102 U.S. Dist. LEXIS 60973). 

There, in an earlier Markman hearing, the patentee had argued that the terms “column bitline” and “row wordline” (in claims for a semiconductor memory cell) were interchangeable, and further that they should be defined identically as “a line that connects to one terminal of each memory cell in a memory array.”  The effect of the patentee’s proposed claim construction was to overcome: specifically, the fact that the arrangement of the “column bitline” and “row wordline” in the accused semiconductor was precisely opposite the arrangement of those components recited in the asserted claims.  Judge Illston initially construed the claims in favor of the patentee.

Later, however, in a parallel inter partes reexamination proceeding, it was the accused infringer who asserted that the claim terms should be construed to be interchangeable, as the patentee had urged in court, with the result that the claims were anticipated by a prior art reference.  The examiner rejected the accused infringer’s argument, finding that the claim terms were not interchangeable and that the prior art reference did not anticipate the claims.  The patentee stated merely that it  “simply agreed” with the examiner.  The accused infringer then appealed to the PTO Board the examiner’s refusal to reject the claims.

In the meantime, the accused infringer asked Judge Illston to reconsider her claim construction, contending that the patentee should be judicially estopped from maintaining inconsistent positions in the two forums.  On Tuesday, Judge Illston agreed that the patentee’s “clearly inconsistent positions satisfy at least the first prong for exercising judicial estoppel,” but she refused to invoke judicial estoppel, fearing that the PTO might also change its claim construction during the appeal:

at this juncture because of the incomplete nature of the proceedings before the BPAI. In its appeal before the BPAI, [the patentee] set forth the mirror image of the argument it makes here. There, [the accused infringer] argues that the Examiner erred by not considering the terms interchangeable. … Applying judicial estoppel and accepting [accused infringer’s] proposed terms here risks the possibility that both this Court and the PTO will switch their own inconsistent positions, leaving these concurrent proceedings in the same incongruous state, though this time, unfairly benefitting [accused infringer]. Nor is the Court convinced that [accused infringer’s] proposed definitions of the terms is correct.  The Court therefore declines to exercise its discretion to invoke judicial estoppel.

(Emphasis added). 

Judge Illston did find, however, that the patentee’s statements to the PTO Board constituted “a clear and unmistakable disavowal of a claim scope that would include gates of transistors that are coupled to row wordlines. in the BPAI appeal.”  She explained that the patentee had “explicitly agreed with – and thereby adopted – the Examiner’s position, a position that was directly contradictory to [patentee’s] position before this Court during claim construction.” 

Whether this disavowal will result in a judgment of non-infringement is not clear, at least not clear to me.  It does seem likely, though, that Judge Illston will revisit the question of judicial estoppel once the PTO Board issues its decision and that she will be reluctant to allow the patentee to benefit from a broad claim construction in court and a narrow claim construction in the PTO. 

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