Effect of arguing claims as a group on prosecution estoppel

Takeaway: Arguing claims as a group can be risky, inviting the court to find that those arguments apply to all claims in the group, even when the claim language differs. But in Seachange International, Inc. v. NCube Corp., 115 F.Supp.2d 473 (D.Del. 2000), the court declined to do so. The Applicant's careful phrasing of the argument, along with differences in claim language, helped the court reach the conclusion that "a member of the public reviewing the entire intrinsic record would be aware that the statements made by the applicant in the relevant portions of the prosecution history could not pertain to claim 37."

More Details: The application included several independent claims which used different language. Claim 37 referred to "through a network for data communications" while claim 1 used the more specific language "point-to-point two way channel interconnection." (Emphasis added.)

The Examiner grouped claims 1 and 37 together in rejecting the claims under § 103. The Applicant argued these claims as a group, using claim 1 as an example to distinguish over the references:

Applicant's claim 1 recites a method in which ... processor systems are interconnected using a point-to-point two-way channel interconnection with each one of the other processor systems. That is, any one processor system can communicate directly with any one of the other processor systems.

However, the Applicant did attempt to avoid having the arguments used wholesale against all claims in the group despite differences in claim language:

Applicant submits that with respect to each group of claims that certain of the claims in the group add further patentably distinct features to the invention and thus are further patentably distinct over the applied references. For simplicity, however, Applicant will in general treat a single claim as being representative of the group of claims but reserves its right to later argue that additional ones of the claims are patentably distinct over the combination of references.

When the patent was asserted, the accused infringer attempted to invoke prosecution history disclaimer to limit the claimed "network" of claim 37 to a network of directly connected processors, based on the "direct communication" argument made during prosecution. Specifically, the accused infringer argued that "the applicant limited the scope of claim 37 to its argument over claim 1 by grouping claim 37 with claim 1 and using claim 1 as illustrative of all claims in the group."

The court disagreed, finding on balance that "a member of the public reviewing the entire intrinsic record would be aware that the statements made by the applicant in the relevant portions of the prosecution history could not pertain to claim 37." The court relied on several factors for its finding:

First, the plain language of claim 1 and claim 37 indicates that claim 37 is broader in scope. Second, the file wrapper clearly indicates that claim 37 (application claim 40) was added to more fully cover the invention. Third, it was the examiner who originally grouped the claims. The applicant clearly indicated that its response was drafted with similar grouped arguments in an effort to achieve simplicity. Moreover, the applicant expressly stated that it believed that the individual claims were patentable independent of claim 1, and that the applicant reserved its rights in that respect. Finally, the arguments made in response to the rejection clearly addressed the subject matter of claim 1 both in substance and nomenclature.

My two cents: When the differences between my independent claims are as great as they are here, I typically argue separately. I doubt I'll change my practice based on this one district court decision. But the next time I do argue as a group, I'll probably add some boilerplate like that used here.