Doctrine of Equivalents at the Federal Circuit

by Dennis Crouch

The chart below  provides a small bit of information – the annual number of Federal Circuit decisions discussing the Doctrine of Equivalents.

Recent decisions:

  • Pharma Tech v. Lifescan, Inc. 2019 WL 6222860 (Fed. Cir. Nov. 22, 2019) (prosecution history estoppel bars the claims for infringement under the doctrine of equivalents)
  • Metricolor LLC v. L’Oreal S.A., 2019 WL 5588874 (Fed. Cir. Oct. 30, 2019) (granting plaintiff leave to amend complaint to add DOE allegation).
  • UCP Intl. Co. Ltd. v. Balsam Brands Inc.,2019 WL 4955052 (Fed. Cir. Oct. 7, 2019) (vacating summary judgment of literal infringement and DOE based upon faulty claim construction).
  • Eli Lilly and Co. v. Hospira, Inc., 933 F.3d 1320 (Fed. Cir. 2019) (narrowing amendment did not create prosecution history estoppel; no disclosure-dedication; district court did not err in finding insubstantial differences)
  • Ajinomoto Co., Inc. v. Intl. Trade Commn., 932 F.3d 1342 (Fed. Cir. 2019) (affirming equivalents determination)
  • VirnetX Inc. v. Apple Inc., 931 F.3d 1363 (Fed. Cir. 2019) (discussing the court’s prior reversal of a jury DOE verdict)
  • Amgen Inc. v. Coherus BioSciences Inc., 931 F.3d 1154 (Fed. Cir. 2019) (prosecution history estoppel barred patentees claiming doctrine of equivalents infringement)

See John R. Allison & Mark A. Lemley, The (Unnoticed) Demise of the Doctrine of Equivalents, 59 Stan. L. Rev. 955 (2007) (DOE used to be important, but not anymore); Lee Petherbridge, On the Decline of the Doctrine of Equivalents, 31 Cardozo L. Rev. 1371 (2010) (confirming the demise and remarking that the result “is the culmination of a concerted and prolonged court-driven effort to make [DOE’s] favorable application the exception, not the rule.”); and David L. Schwartz, Explaining the Demise of the Doctrine of Equivalents, 26 Berkeley Tech. L.J. 1157, 1159 (2011).

34 thoughts on “Doctrine of Equivalents at the Federal Circuit

  1. 8

    Hard to believe post Mark A. Lemley’s admissions that he has been making 10’s of millions burning down the patent system with his Google executive wife and that there are zero protections against unethical conduct from Lemley that you would cite to him.

    Erase Lemley from the record. His bank account is the body.

    1. 8.1

      Last time I checked the US patent system had spewed out a record number of patents, and I would bet that a substantial number of them belong to Google.

      Sure is a funny way of “burning it down.”

      Here’s an idea: go up on a hilltop, proclaim to everyone the deep hurt caused to you by this great injustice, and then blow your br-@-ins out. You’ll start a revolution! Sure you will. Nobody will laugh and call you a ridiculous entitled Rich Whitey worshipping pile of pig sh-it.

      1. 8.1.1

        Here’s an idea: go up on a hilltop, proclaim to everyone the deep hurt caused to you by this great injustice, and then blow your br-@-ins out.

        Follow your own advice, Malcolm.

  2. 7

    The “Doctrine of Equivalents” is of course a judicial balancing act, to allow patent suits against parties who do not literally infringe any of a patent’s claims where the patent owner can convince the court to excuse the failure of that applicant to obtain a claim covering some unappreciated alternatives for some claim elements, where the same result is being achieved in essentially the same way by that alternative. Even though that conflicts with the fundamental requirement that the claims define the invention, and must do so without ambiguity and uncertainty. The latter would be far less of a threat hanging over investors and manufacturers if the unknowable in advance [or in scope] effective claim broadening of a DOE decision were to be subject to the partial intervening rights protection provided for all other post-issue claim scope changes – in reissues, reexaminations, IPRs, etc. Thus, should not those wanting to increase the application of the DOE consider promoting such legislation?

    1. 7.1

      I do not see your alleged “conflicts with the fundamental requirement that the claims define the invention, and must do so without ambiguity and uncertainty.

      You insert a conclusion that you need to prove.

      The reality of the situation is that words themselves are limited, and capture (and protection) for innovation — alone being novel and not obvious — will naturally run into the limits of language.

      The notion of “partial intervening rights” is utter balderdash, a veritable Efficient Infringer’s wet dream. Such ONLY invites mischief from the well-monied established entities that would rather compete on non-innovation factors.

    2. 7.2

      Along the same lines, you’d think that the great uncertainty of the outcome of a DOE offense would disturb those folks who have been shrieking endlessly about the (alleged but not really true) lack of predictability in cases that raise obvious 101 issues (i.e., cases involving information, the application of logic to information and data, determining the meaning of data, detection of naturally occurring molecules, etc).

  3. 6

    I and others have been on top of this issue for years, but if the patent maximalists (and d—bsh-t water carriers like GregDeL) ever do achieve their fantasy of patenting information (like correlations) and the use thereof in prior art contexts, let nobody say that it wasn’t predicted (and very predictable):

    link to

  4. 4

    There is a large degree here of re-writing history with a supposition that DoE was a “bad thing” that through activism (academic and judicial) was “reigned in.”

    The more accurate historical account is merely that the hysteria of how bad DoE was simply lost its momentum and died a natural death when the anti-patent propaganda machine moved on to other targets.

    1. 4.1

      The DOE is a creation of “judicial activism”. It was reined in (ultimately by the Supreme Court) because it threatened to become a runaway train unless reasonable limits were put on the doctrine.

      It’s not “anti-patent” for such events to take place, by the way. Only a total patent-huffing maximalist id-jit like you would suggest otherwise.

      1. 4.1.1

        While you contemplate the reply below at 2.1, please feel free to back up any of your assertions with actual citations.



          Because Bildo is all about “citations”.

          Go f yourself and your bizarre, nonsensical revisionist history Bildo.


            You accuse others of being revisionist when challenged to support your position in the first instance.

            Methinks that it is YOU being revisionist (or least, simply making things up).

            You appear to have no facts to pound.

            You appear to have no law to pound.

            All that you have is your table of feelings and ad hominem.

            That – you pound and pound and pound.

  5. 3

    Looking in from the outside, I find it interesting that just as the courts in the USA shut down the DoE the Supreme Court in the UK has opened up the Doctrine, in an effort to deliver, on a perceived need to give inventors a scope of protection that is fair, in the sense that it is commensurate with their contribution to the art.

    How is it, that the Supreme Court in London perceives this pressing need? Why, because the EPO is ever more assiduously enforcing a “First Inventor to File” priority regime for granting patents. Only that precise invention on which you were the first to the Office with a sufficient, enabled WD is prosecutable through to issue.

    In the context of patent law in the USA, there is ever talk about swings of the pendulum. As FItF asserts its presence ever more strongly in the courts of appeal in patent infringement cases in the USA, I expect to see a return, in due course, of a DoE that is significant. Remember, trends that Prep and Pros types observe today are recognised by the denizens of the higher courts only 10 or 15 years later.

    1. 3.1

      “..trends that Prep and Pros types observe today are recognized by the denizens of the higher courts only 10 or 15 years later.”
      ? It’s more like the other way around in the U.S., as would be expected, since higher court decisions control and some full time P&P personnel do not do CLE. E.g., inequitable conduct, 112(f) claim scope & consequences for lack of enablement, spec admission words like “the invention comprises..,” prosecution laches, proper claim scope, the need for P&P to do more than get an application to get past a brief examiner search to be enforcable under AIA decisions, etc., etc.
      And of course, DOE has no place to even be lawfully considered in P&P.

      1. 3.1.1

        And of course, DOE has no place to even be lawfully considered in P&P.


        Paul, stick to something you know. I recognize that once upon a time you had a registration number and may have engaged in prep and pros, but clearly this is something outside of your current knowledge.


          If you are reversing what I actually said, then of course narrowing claim amendments done in P&P can impact DOE later in patent litigation. That is the subject of the very first decision Dennis cites above, The point was that DOE is not considered in, or even raisable in, P&P. Only doing P&P work does not expose one to DOE law arguments or rejections. If you have any PTO MPEP cites to to the contrary, let us know.


            If I am…

            No. That is not what I am doing. I am challenging your notion that one doing prep and pros need not be mindful or aware of DoE.

            While certainly the items that you mention that occur only after grant in a litigation setting actually happen in that setting, to propose as you do that prep and pros can happen (should happen) in a vacuum of such later events is preposterous. That your words carry this effect only shows how disconnected you have become from prep and pros.


              Paul was obviously referring to the fact that the DOE is never raised as an issue by the PTO during exam. Good grief, Bildo, just stick to writing your own cr @ppy comments.


                Good grief Malcolm, my comments already take into account that the post grant use of Doctrine of Equivalents is not something that happens in prosecution, but at the same time it is important to know of (and protect the later ability to use) the Doctrine of Equivalents during prep and pros that shows the error of Paul’s comment indicating that people doing prep and pros need not keep the concept in mind.

      2. 3.1.2

        Thanks for that comment, Paul, which reminds me not to extrapolate out from Europe, where the Supreme Courts of the 38 EPC Member States take 20 years (sometimes considerably longer) to settle on the already established patent validity jurisprudence of the Enlarged Board of Appeal of the EPO.

  6. 1

    If ever there was a “plague” of runaway doctrine at the CAFC, it was the so-called DOE.

    But of course that plague was mostly favorable to Rich Whitey … so it would be sooooo uncivil to refer to it negatively. “Personal property rights!” Rich Whitey is always super concerned about that, as long as we aren’t talking about trivial stuff like the right to use your own computer to do math, or correlate a fact about your own body with another fact.

    1. 1.1


      Malcolm, I think that you simply must not be aware of how you sound when you go on these types of rants.

      1. 1.1.1

        Oh, right, I keep forgetting that expanding patent rights for Rich Whitey is also really high on the list for a huge majority of the people who aren’t patent attorneys and who aren’t in the top 1% of the economy. In fact, it’s a huge priority for the black people and poor people I know. They really want to pay for those new correlations and “best yacht for you” type apps that we are starving for in the US right now.


        And look in the mirror you p.o.s.


          As I said, you are clueless how you come across with your racial intonations.

          That you appear to be taking yourself seriously makes one single person doing so.


            Oh noes! Someone criticized Rich Whitey on the Onternets!

            This is worse than Campus PC which is the worst thing ever according to r@-cist @-wipes like Bildo!

            The commies are coming! The commies are coming!

            Seriously, snowflake: you are a piece of work.


              You don’t get how inane you are playing the “R” card so out of tune with ANY substantive point for the patent law point at hand, do you?

              Your feelings are all that are important to you — just like a certain President.

Comments are closed.