The doctrine of equivalents is often treated as the legal equivalent of going "c'mon....c'mon! its all the same."
It's not uncommon to see it included in infringement contentions in terms that just note that, to the extent the noodlewiggler (TM) does not literally infringe claim 38 of of the '123 patent, it's insubstantially different, and performs the same function in the same way to achieve the same result, and is lame."
Judge Andrews issued an opinion today that neatly illustrates the problem with that tactic. The defendant in Carrum Techs., LLC v. Ford Motor Comp. C.A. No. 18-1647-RGA (D. Del. Nov. 9, 2023) (Mem. Op.) moved for summary judgment on the basis of a claim construction argument the parties had not previously briefed. In the f briefing the issue, the Plaintiff submitted an expert declaration stating that, even if the Court agreed with the Defendant on the claim construction issue and thus found no literal infringement, there was still infringement under the DOE, and provided a brief analysis under the function/way/result test.
To begin he noted that a boilerplate reference to DOE ("C'mon....") in the contentions was insufficient to preserve the issue. In particular he found the passage below lacking:
To the extent Ford's Accused Products do not literally meet this element of the claim, each of the Ford Accused Products meet this limitation under the doctrine of equivalents because any difference between the Ford Accused Products controllers and communication network and this claim limitation are insubstantial and/or perform substantially the same function, in substantially the same way, to achieve substantially the same result. ...
Id. at 13.
He then went on to hold that a declaration in response to an SJ brief was way to late to flesh out this insufficiently disclosed theory:
I think Plaintiff's DOE theory and related expert declaration are untimely. When considering a summary judgment motion, I may refuse to consider expert reports submitted after the deadline for expert reports. Here, Plaintiff advances a DOE theory for the first time in its opposition to Defendant's summary judgment motion. Defendant was never given the opportunity to confront Dr. Shaver on his new DOE opinion, and it would be prejudicial to allow Plaintiff to now rely on that opinion. Plaintiff has introduced its DOE theory too late.
Id. at 14 (internal citations omitted)
He thus granted SJ of non-infringement.
I think the clear lesson here is that, while it may be a pain to articulate a DOE theory in opening contentions, it frequently does not present significant extra work on top of the already onerous task of putting together contentions. A little extra gloss -- such as describing the function, way, and result for these elements -- might have been enough to save the day and get the Plaintiff their day in trial.
Also please DM me if you would like to invest the noodlewiggler (TM). We have recently resolved all pending litigation and are seeking series A funding. I don't think I need to tell you what it does.
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