A cautionary tale about extensions of time

I ran across an interesting post "Wait One Day, Lose Two Days " on the blog 12:01 Tuesday (a blog with interesting tidbits about just-issued patents).

The blog post is a cautionary tale about the dangers of taking extensions-of-time during prosecution of applications that have long claims to priority: an application with a priority claim back to 1999 expired before it issued, apparently due to Applicant delay.

Prosecution History Estoppel and Prosecution Disclaimer

Many practitioners use the term "prosecution history estoppel" to refer to any limits on claim scope that arise from actions taken during prosecution. It turns out that, strictly speaking, the doctrine is more narrow than this.

Prosecution history estoppel is limited to the doctrine of equivalents context — actions taken during prosecution estop the patentee from invoking infringement under doctrine of equivalents. The related doctrine of prosecution disclaimer affects claim construction — the patentee disclaims scope through actions taken during prosecution.

If you want to know more, read this article at IP Today. And if you can't get to that article because it's "subscriber only", here is a CLE paper discussing disclaimer. The CLE paper is much longer, but the discussion of disclaimer vs. estoppel is on the first page of the main article.

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.

Does submitting a product brochure risk prosecution history estoppel?

In an ideal world, you want to help the Examiner to understand the invention, so that you can quickly obtain a patent on the inventive features. But the reality is that the Examiner is not the only one you're prosecuting in front of. The doctrines of prosecution history disclaimer and prosecution history estoppel give an accused infringer ammunition to attempt to limit the scope of the claims. Thus, many patent prosecutors are very careful when making arguments that distinguish the claims from the prior art.

That's why I was surprised to see a response in which the Applicant submitted a product brochure to the Examiner and made the following statement:

    First, in order to aid in the Examiner's better understanding of the present invention, enclosed herewith are brochures of the "Voyager" electronic device which depicts the technical features and advantages of the present invention.

When I ran across this file history, here's what occurred to me: could an accused infringer attempt to construe the claims to include these features from the brochure? Product brochures are often full of details and product advantages — two things that I don't want to be read into the claims. I don't think that a court should, or even would, read such features into the claims. But why give the accused infringer something to argue about?

I note that the practitioner did limit the actual arguments to the claim language, rather than arguing outside the claims, so that might reduce the risk. But I'd think very carefully before submitting a product brochure to help distinguish over the art.