Construing Claims as of their Effective Filing Date

A short aside from Dennis Crouch

In Phillips v. AWH, the en banc Federal Circuit included an oddball statement regarding PHOSITA perspective in claim construction.  The court wrote that the focus is on the meaning to PHOSITA “at the time of the invention, i.e., as of the effective filing date of the patent application.”  I call the statement odd because it incorrectly states that the time-of-the-invention is the same as the patent application’s effective-filing-date. The difference can be critical — although word-meaning changes slowly over time, recent invention is an important trigger for rapid definitional change.

Regardless of whether the Phillips statement is correct, going forward for Post-AIA patents, the court should now eliminate “the time of the invention” from its claim construction process.  Under the statute, all of the focus now is on the effective filing date with invention shifted to a mere historic element of the patenting process.

Stepping Back: One problem with any time-of-the-invention analysis is that the traditional legal definition of invention involves a potentially wide temporal expansion.  Remember, invention begins with conception but is not completed until the invention is reduced to practice.  The patent courts added further to this by finding the filing of a patent application to be a constructive reduction to practice that completes the invention process. Because most patent applications are filed prior to a complete reduction to practice, for most patented inventions the time of invention completion is the same as the effective filing date of the patent at issue.


78 thoughts on “Construing Claims as of their Effective Filing Date

  1. 6

    One should measure invention from the date of invention and the meaning what one writes from the date one writes it.

    1. 6.1

      I’m not sure that’s fair either. Some might not download a new lexicon on a weekly basis like its an anti-virus definition set. Do you? For instance, some in the mechanical arts might use words like -adjacent-and -elongated- today, the same way they have used them for the past 20 years. If their meanings have morphed over that time period…. they might not have gotten the tweet.
      #DrafterOfPossiblyOutdatedSkillInTheArt. #DOPOSITA


            I did. He said, inter alia: “One should measure … the meaning what one writes from the date one writes it.”


              When one is writing in an ex post facto situation – ad occurs when one is writing a patent application – one is writing for an item that has occurred previously.

              Do you recognize this fact?

    2. 6.3

      As a corollary, consider an inventor who publishes and then files a year later. The publication prevents anyone filing anywhere in the world after the data publication from receiving a patent on the published invention. And yet, if someone, anywhere in the world, files an application on the same invention and then files in the United States after the date of publication but before the US applicant files, the inventor who published first is himself denied a patent even though that publication cannot be used against the inventor in the United States as prior art. The result here is absurd.

      How can or even should a patent application filed on an invention previously publicly disclosed in a publication by another be allowed to invalidate a patent application filed by the inventor of the invention disclosed in the publication?

      Obviously, the inventor should have a right to a priority to the published application. He is the first to disclose the invention to the world in a publication thereby preventing anybody else but him from receiving a valid patent on that invention or even obvious variants of it. It is harsh and unreasonable to deny this inventor a patent on the published invention under these circumstances.


          anon, are you suggesting that other have a right to obtain patents on obvious variants of a published invention?


            Quite the opposite, Ned – no one has a right to obvious variations of something in the public domain.


              (I think that you mean to ask a different question. Perhaps you mean to ask why the H did Congress eviscerate the one year “protection”…)

      1. 6.3.2

        Ned, could it be that the co-existence of i) First to File ii) a one year Grace Period, and iii) USA membership of the Paris Convention, in your opinion leads to absurd results?

        If so, which of the three has to go, to cure the absurdity? First to File, I suppose you would say.

        You don’t say anything about any strong “Right of Continued Use” which we find in Europe and which protects those who publish (for whatever reason) their invention and then decide at a later date that a patent would be nice.


              Thanks MaxDrei, I will give it a look.

              Is it your experience that the allowance of each country to implement its own “take” creates a diversity or patchwork of laws to be aware of?


                No. Because each EU Member State aims (in its own language) to implement the common provisions of the European Community Patent Convention (which is not the same as the 38 Member State European Patent Convention). In my experience, they have succeeded.

                Here is a Link to a real case on Section 64:

                link to

                As you see, it concerns a commercially important pharmaceutical.

                As you see, the scope of Sect 64 is assessed as narrow.

                Cases on Section 64 are rare birds. Section 64 tries to do justice between parties who both made the same invention, independently of each other, around the same date. I’m sorry you think it renders the patent system weaker. I think it makes it stronger. I suppose one’s view depends on where one is coming from.

                1. Not at all.

                  A “strong” patent system is one that is robust enough to endure, one that commands respect, one that adjudicates fairly between all stakeholders who enjoy binocular vision, all those who really do want to promote progress in the useful arts.

                  A system that is increasingly disparaged as “broken”, one that only one-eyed vested interests find “strong”, one that forever needs another tweak in order to run properly, is the very antithesis of a “strong” patent system.

                2. The weakness induced by the lack of the stick makes the offer of the carrot weaker as well.

                  There is NO “strong patent system” possible with this type of lessening the value of the patent.

                  Your “all parties” merely sounds in Infringer Rights rhetoric.

                3. Those not liking strong patents will ALWAYS disparate them.

                  Your comment is circular, self fulfilling and meaningless.


              I think that the text makes patent rights weaker, and very much prefer the traditional US style of patent rights having BOTH “carrot” and “stick” approaches.


                …so while I respect the right of the U.K. sovereign to choose this type of IP law, it just does not fit well with the US sovereign’s traditional view of “exclusive” (notwithstanding the recent denigration of that same strength with the PUR of the AIA, and the limited subset of the similar previous measure for business method patents)


          Max, I have no serious problem with prior user rights and I think the way they are set up in English law it makes a lot of sense.

          Regarding first-to-invent versus first-to-file, I think the main objection we had in United States was directed to secret prior art. Prior invention that becomes prior art as of the date of invention upon producing a product, publishing a description was always a bad idea. There is a difference between invalidating patents over secret prior art and allowing an interference between rival applicants to the same invention where the respective dates of invention are considered.

          Thus when the inventor publishes his invention and then files within a year, he has a grace period that is good against his own publication. But this act provides no benefit at all if others suddenly file on the same invention before the inventor files. Clearly, in my view, either there has to be an interpretation that the second filer on an invention that has been publicly disclosed in a printed publication is not an inventor. An inventor must create something new that the public does not already know at the time of invention, which is no later than the date of filing. If it is already known, the purported inventor cannot legally be an inventor.

          I would think there has to be an amendment to the statute in United States to fix this problem, or a creative interpretation of the courts that would prevent a filer, filing after the date of publication of the invention by another, from being deemed inventor so as to deny a patent to the inventor of the invention that is disclosed in the publication.

          But back to secret prior art in general, patents and published patent applications should not be prior art as of their filing dates. Their priority dates should only be used in a contest with another inventor claiming the same invention. In other words, the first to file gets the patent if two inventors are claiming the same invention.

          And, if we want to eliminate interferences entirely, we can simply say that the first patent to issue on an invention is valid and the second is invalid. But in either case, the respective filing dates are irrelevant.


            Ned, if this is too brief, please forgive.

            The “bargain” is limited term exclusive rights in return for disclosure. Disclosure occurs 18 months after the filing date. First to file is first to disclose.

            Why give 20 years of exclusive rights for stuff already disclosed to the public?

            Under the EPC, only prior-published stuff can be used in obviousness attacks. Earlier filed stuff is allowed in novelty attacks to stop double patenting of the same stuff. Only the first to file can get a patent.

            The scheme makes sense. It has to. It got enacted in 1973 only by being acceptable to all EPC Member States. I haven’t seen yet any informed criticism of the scheme that stands up to analysis. I think it a pity that the USA couldn’t bring itself to sign up to it too.



              Your statement of:

              Why give 20 years of exclusive rights for stuff already disclosed to the public?

              Has a deeper meaning than I think that you appreciate.

              Read again the Katznelson article – your errant view limits the proper appreciation of what Ron is saying.


              Max, under the US scheme, disclosure is first, then filing. I actually see no problem with this, and I agree to PUR to those who make/use prior to the filing date. But the bargain is there, and the public disclosure is far earlier.


                I grant you the public disclosure occurs earlier, by the length of the grace period, plus 18 months. Trouble is, the black hole of uncertainty, what claims the other fellow has got pending at the USPTO, is also longer, by the length of the grace period.

                Now you may say “So what” but I happen to think that promoting the progress, stimulating investment in new technology, requires that the duration of the black hole be minimised, not extended to 2 1/2 years or more. That, I think, puts a brake on investment.

                1. …then you must really dislike the ability to file additional broader claims within two years AFTER grant of the patent (and not to mention the typical continuation practice)…

                2. I can live with continuation practice. Even at the EPO you can “have something pending” all through the life of a patent, using successiove generations of divisional filings. That’s not a problem, if there is a strict and unavoidable prohibition on adding to the disclosure of the application as filed.

                  Patent law in the USA is laden with Get Out of Jail Free Cards for those who are poor patent drafters. The post-issue 24 month grace period to draft a decent set of claims is just one of them. Not surprising, given that the USA has only one profession, whereas the ROW has two distinct professions, and, for its separate patent attorney profession, competent drafting is the alpha and omega of professional competence.

                  The public has a right to expect those who draft patents to get it right first time, don’t you think?

                3. You can “live with” the very thing you complain about (and then top it off by being confused on broadening amendments within two years, as the US does have a “no new matter” requirement.

                  Please take the time to realize how disjoint your “answer” is.

                4. Max, the 2 1/2 year period, publication of invention to publication of the claims, is the way it is now.



            Of course you have “no problem” since one of your claims to infamy is creating those things, iirc…

            The start of your Windmill chase against business methods – and one of your greatest (legal logic) failures in that the adoption of the limited PUR dealing with a subset of business method patents clarified the intention of Congress to NOT eliminate business method patents as eligible subject matter (one does NOT need a limited defense against something that is “plainly” ineligible – as I have often put to you; and as you have – as often – run away from).

            I wonder how much that galls you – to have a hand in proving that your own Windmill Chase is false…


            >>Thus when the inventor publishes his invention and then files within a year, he has a grace period that is good against his own publication. But this act provides no benefit at all if others suddenly file on the same invention before the inventor files.

            Any practicing entity would see preventing others from acquiring a patent to be a ‘benefit’.

  2. 5

    It would be more useful to judge the entire patent as of the date of the invention – not just for claim construction purposes, but to freeze the law as of that date, because the bargain the inventor makes is to disclose in return for protection, but in recent years, the scope of that protection (availability of injunctive relief, judge-made exclusions from patentability, etc.) have significantly narrowed long after the filing and issuance of the patent, thus moving the goalposts for inventors who played by the rules as they were understood (not only by the inventor, but by the PTO and the courts) at the time of filing.

    1. 5.2

      Useful? Not sure I follow you, Lawrence. Consider this:

      I make things. I show you an issued patent because I’m worried I might infringe.

      But I think the claims are not valid and I want to check out validity issues.

      So, with your useful concept, I need to know “the date of the invention”, right?

      Who is going to tell me that date, so I can then start to look for “prior art”?

      But key is “the bargain” disclosure for protection, as you correctly observe.

      Now then disclosure is what happens on the filing date. It does NOT happen on the date of invention, right?

      1. 5.2.1

        Disclosure does not happen on the filing date.

        It happens on the publication date.

        This has important ramifications to ANY publication prior to grant scenario.

        Are you sure that you want to pursue this Quid Pro Quo path in a strict manner?

  3. 4

    Of course, the move to FtF removes at a stroke all the hand-wringing about constructive vs actual reduction to practice, as well as any debate about conception or diligence. From now on, the only thing that matters is whether the disclosure on the filing date contains a written description of the claimed subject matter and also enables it, across the width of the claim. Deadly simple in theory, much more tricky in day to day practice.

    As Dennis notes, the populating of the claimed area, with embodiments (prophetic or real) goes on even after the filing date, in a large proportion of cases. After y year, there is more to say about the invention in, say, your non-pro or PCT filing. That’s what makes it so interesting, under FtF, deciding whether any given claim is or is not entitled to its USPTO or Paris Convention priority date. Deadly simple in theory, deciding under FtF what is the “date of the claim” but, take it from me, tricky in day to day practice.

  4. 3

    DC most patent applications are filed prior to a complete reduction to practice

    That’s an interesting assertion.

    Is there data showing this to be the case? Has it always been the case or is it a recent phenomenon? Is it true “across the board” or is it true mainly for particular art units?

    My experience in chem/bio is that that “innovations” that exist only on paper (i.e., constructively reduced to practice, without a single embodiments manufactured and tested prior to filing) are the rare ones. They are also the ones where the “inventor” brings the least to the table and probably the attorney should be listed as a co-inventor some of the time.

    A patent system that favors or promotes the filing of applications prior to the reduction to practice of any embodiments will end up favoring speculation by scriveners and gamesters over the work of skilled artisans. But, hey, if the “patent courts” want it this way and if it favors patentees, then it’s not judicial activism and it’s totally the way the Framers wanted it.

    1. 3.1

      My experience in chem/bio is that that “innovations” that exist only on paper (i.e., constructively reduced to practice, without a single embodiments manufactured and tested prior to filing) are the rare ones

      LOL – except those that have to go before the FDA. Look at the drop out rate of items not hitting the utility mark (and ALL of these are filed before actual possession, admittedly a slightly different topic).

      1. 3.1.1

        …and I am also curious as to which court case it is that rewrote which law written by Congress that permits this “constructive reduction to practice” view…

      2. 3.1.2

        “anon” LOL – except those that have to go before the FDA.

        Happy to be wrong about this, but I doubt that most chem/bio innovations are FDA-bound. That said, in my experience even the applications that cover FDA-bound products are usually more than mere paper as of the filing date. There’s typically at least one embodiment that’s been made and tested on a mammal, or some other relevant organism (and the relevance will depend on the particular facts). Going forward without that kind of data in the application has the effect of weakening one’s arguments about the prior art (which is filled with all sorts of suggestions …).

    2. 3.2

      Thanks MM – Some good points here. I was thinking about this issue as I was writing and I don’t believe that I have good data right now to support my assertion except for a substantial number of anecdotal statements regarding applicants inability to prove a prior invention date pre-AIA. I would suspect that even in your chem/bio cases that only a subset of the claimed embodiments and features have been reduced to practice.

      1. 3.2.1

        When was “actual reduction to practice” changed…?

        Malcolm’s post indicates this to be a Judge-made rule.

        I am not so sure. IIRC, this changed when Congress made the change from requiring an actual model to a mere paper.


          Anon –
          Prof John Duffy’s article titled Reviving the Paper Patent Doctrine is instructive here.
          link to

          Although he does not suggest it in the article, implementation of the AIA move away from our first-to-invent rules could be relied upon by the courts as a signal to also move away from the strong constructive-reduction-to-practice regime.


            In other words, there is NO actual case law directly on point – and this is merely an academics “wish” to revive some past musings…


            I would rather go with the historical (award winning at that) writing indicating that the original patent system was built so that there was no requirement for “doing,” and which leads away from the “actual reduction” mindset (and its attempted zombie-like revival).

            I will also note that this very much appears to be along the line of the attempted revival of “the mental steps doctrine,” and would (again) invite you or your academic friends to revisit that doctrine er, exploring exactly why it was generated, and exactly what its past limitations were (and why that doctrine saw its demise).


              Nonsense Anon, you are as usual trying too hard to say something insulting even to Dennis. A filed patent application with a description of the invention and an adequate enablement has been considered a constructive reduction to practice of the claimed invention in the case law even for interference litigation purposes from a long time before anyone alive has been practicing. Even in ancient era of patent models the models did not all have to actually perform what was claimed. Even before the AIA the vast majority of those who filed their application first normally won interference invention date contests, except for a minority of cases in which the other party who had filed later had adequate proof a complete actual reduction to practice of the claimed invention prior to the earlier filing date, and per 102(g) that prior actual reduction to practice also had to not have been “abandoned, suppressed or concealed.” And see also the first part of pre-AIA 102(e).


                Nonsense yourself Paul.

                If you want to see an insult in that, it is YOU that is trying too hard.

                1. …and you should be aware that your defense of the constructive reduction to practice is actually in my favor – but you are FAR too much in a hurry to be anti-anon to even realize that.

      2. 3.2.2

        DC: I would suspect that even in your chem/bio cases that only a subset of the claimed embodiments and features have been reduced to practice.

        Of course. It’s hard to find the time to test every variation within certain large genuses. And sometimes that means giving up coverage of that genus.


          And sometimes that means giving up coverage of that genus.

          I am not sure that you read what Prof. Crouch wrote. Your answer implies that claims are not filed on those items that have not been vetted and reduced to actual practice, while Prof. Crouch is saying “only a subset of the claimed embodiments and features have been reduced to practice..”

          The disconnect is not likely to be accidental.

          I am still waiting for someone to provide the statutory law that requires samples and/or actual reduction to practice…

    3. 3.3

      A patent system that favors or promotes the filing of applications prior to the reduction to practice of any embodiments will end up favoring speculation by scriveners and gamesters over the work of skilled artisans

      Got any data on that? And I do mean scientifically valid data (not your “feeling” data).

      1. 3.3.1

        Got any data on that?

        Not that I need any “data” to support a common sense proposition like that but, yes, I have about twenty years’ worth.

        I know it’s hard for you to believe but a lot of the “anti-patent” decisions and legislation that bother you and your c0h0rts so much is directed (explicitly or implicitly) to counter-acting the trend I described.

  5. 2

    I welcome this posting because I for one think that the switch from FtI to FtF changes more than just this. In particular, it changes the date on which obviousness is to be assessed. In any FtF jurisdiction, obviousness is judged as of a date AFTER the invention has been made, AFTER any patentability search has been conducted, and, most importantly, AFTER the specification and claims have been written.

    In practice, what that means is that you can use in the obviousness analysis what the Applicant put into her patent application about the technical field and the problem solved by the invention, to set the case up optimally for recognising an inventive step, without indulging in any ex post facto analysis.

    People on these boards criticise the EPO’s Problem and Solution Approach, that it indulges in hindsight. But in a FtF environment, it doesn’t. The criticism is not well-founded.

    As the USA will be finding out, very slowly, as the repercussions of moving to FtF gradually reveal themselves.

    1. 2.1

      Yes Max, I assume what you are referring to as a major AIA change was the elimination of [often dangerous] ex parte Rule 131 declarations “swearing behind” one’s filing date back to an alleged earlier invention date to dispose of patent application prior art rejections. [They were never effective for actual interferences.]
      I believe that was clear enough to most U.S. patent practitioners at the time – it was certainly discussed on this blog.
      But it did not make that much actual difference. Patent claims obtained with those uncontested ex parte Rule 131 declarations were rarely successfully litigated, and in some cases even became IC issues.

      1. 2.1.1

        No Paul. What I have in mind is the way the EPO uses the Applicant’s own specification to divine the “objective technical problem”. It is this OTP which is then used to determine whether an inventive step separates the claimed subject matter from the state of the art.

        For FtI’ers, this way of doing obviousness is cheating. For FtF’ers, it is perfectly legit.


          If you meant the EPO wants a “problem-solution” statement written into the applications themselves,* yes, but I do not think that was the issue Dennis was referring to? Common POSITA or even local usage of many technical terms changes over time. Prior to the AIA there were a few occasions when that time difference might arguably made a word interpretation difference. In particular, for some words in contemporary supporting evidence documents being used in Rule 131 declarations or interferences or patent suit 102(g) defenses for alleged pre-filing invention dates.

          *Although many U.S. applicants have avoided writing a “problem-solution” statement into their applications, concerns for avoiding Alice-101 rejections have spurred some reconsideration. Some of that was due to calling such “problem-solution”statements “the invention” or putting such a statement under the dangerous and not validly required specification subtitle “Summary of the Invention.”


            Paul, I think you are over-complicating the issue I want to flag up. All I’m saying is that in any FtF system, one assessing inventive activity on the filing date, relative to anterior events including the writing of the patent application.

            Conversely under FtI, where one has the mindset that writing the application is something that happens later in time than the act of invention.

            You might tell me it matters not at all, but my perception is that it makes a heccuva difference, in reality.


            Although many U.S. applicants have avoided writing a “problem-solution” statement into their applications, concerns for avoiding KSR rejections

            Fixed for you, Paul.

    1. 1.1

      What Dennis says makes even more sense considering that most “meaning to a PHOSITA” arguments are arguments as to what was written in the application as filed means. If there was ever a time at which definitions and uses of words should be most carefully made, it should be in in drafting claims and specifications.

    2. 1.2

      How? What benefit does one get for an unpublished “ACTUAL reduction to practice” for post-AIA [non-interferences] applications?

      1. 1.2.1

        Paul,, Neither of your comments pertain to my post.

        Think of the difference between constructive and actual reduction to practice. Then ask yourself what tone do you see in the good professor’s writing here (hint: “Because most patent applications are filed prior to a complete reduction to practice“).

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