Global Prosecution Argument Trumps Doctrine of Claim Differentiation

In Seachange International, Inc. v. C-Cor, Inc. (Fed. Cir. June 29, 2005), claim 1 of the patent required "interconnecting each one of said processor systems in a point-to-point two way channel interconnection with each other one of said processor systems." Claim 37 was identical to claim 1, except that claim 37 requires only that the interconnection be through a "network for data communications." Nonetheless, the court concluded that there had been "a deliberate surrender of claim scope, unmistakable in its effect because it is not suitable to multiple interpretations" so that the broader claim language was also limted to point-to-point communications.

The court noted that on the one hand, an IEEE technical dictionary definition of "network" does not suggest the point-to-point limitation and the doctrine of claim differentiation creates a presumption that the limitations in claim 1 and claim 37 are of different scope. On the other hand, it also noted that written description consistently refered to the network interconnections as point-to-point, and that global arguments had been made during prosecution with regrd to these two claims in an single, exemplary group:

The Examiner grouped several claims together, including claims 1 and 37
(40), and rejected them as a group as being obvious over Morita in view of
Benner. Applicant responded, stating, inter alia, that applicant will in general treat a single claim as being representative of the group. Applicant then selected claim 1 as "an illustrative claim" and argued that Morita and Benner do not suggest connecting each processor to each other processor via point-to-point, two-way channel
interconnections. Applicant also argued that Morita and Benner do
not disclose "the arrangement of stored data and redundant data" required by
claim 1. Applicant concluded that "in view of the fact that neither Morita nor Benner . . . suggest the above-mentioned elements of Applicant’s invention . . . , it is submitted that the rejection has been overcome by argument."

Even though Applicant "reserve[d] its right to later argue that additional ones of the claims are patentably distinct over the combination of references," Applicant made no separate patentability argument for claim 37. Because Applicant provided "clear
notice of th[e] linkage" between claim 1 and claim 37 for the purpose of its argument to overcome the prior art rejection on the basis of the "point-to-point" and "redundant storage" limitations, it would be improper to now broadly construe claim 37 not to contain those limitations. See Elkay, 192 F.3d at 980 (holding that arguments made with respect to a claim during the prosecution of an earlier patent applied to a claim in a later patent where the claims were "affirmatively linked" by the applicant); Digital Biometrics, Inc. v. Identix, Inc., 149 F.3d 1335, 1347 (Fed. Cir. 1998) (holding that a general statement distinguishing prior art applied to all claims linked to the statement).

Seachange argues that Applicant made two arguments to overcome Morita and
Benner, and because the "point-to-point" argument relates directly to the "point-to-point" language of claim 1 rather than the "network for data communications" language of claim 37, and because the "redundant storage" argument relates to all claims of the grouping, the public was on notice that claim 37 did not necessarily contain the "point-to-point" feature. Seachange buttresses this argument by citing the notice of allowance in which the Examiner allowed all claims based only on the
"redundant storage" feature.

However, the conclusion that Seachange would have us reach—that Applicant responded to the First Action and distinguished claim 37 over Morita and Benner based only on the "redundant storage" feature, and not based on the point-to-point feature—is unwarranted. Nothing in the prosecution history suggests that the point-to-point argument did not apply to all of the grouped claims. Applicant did not indicate that the "point-to-point" argument applied only to claim 1. Instead, the natural reading of Applicant’s statements suggests that the "point-to-point" argument applied to each claim in the grouping.