Construing the claims to include technical effects mentioned in the description (T 1924/20)

Claim interpretation is the current hot-topic at the EPO, specifically the extent to which the description should be taken into account in claim interpretation. The EPO has recently taken a hard line against using the description to narrow the meaning of clear language in the claims. There is, however, another line of recent EPO case law which has taken a similarly hard line on requiring the description to be amended in line with the claims. According to these Board of Appeal decisions, inconsistencies between the claims and the description would confuse the skilled person over how to interpret the claim language. To this Kat, these lines of case law are incompatible: either clear language in the claims should be interpreted in view of the description, or it should not, the EPO cannot have it both ways (IPKat). To complicate things further, there is also mounting Boards of Appeal case law finding the contrary position on description amendments, i.e. that the description does not have to be amended in line with the claims (IPKat). 

No hearing aids necessary

It is thus becoming increasingly clear that a referral to the Enlarged Board of Appeal on claim interpretation is necessary to harmonise Boards of Appeal case law. In this context, the recently published Board of Appeal decision in T 1924/20 adds further weight to the line of Boards of Appeal case law that the description is irrelevant to the interpretation of otherwise clear claim language.

Construing the claims to incorporate a functional effect from the description

The decision in T 1924/20 is interesting for its rejection of an approach to claim interpretation whereby functional effects mentioned in the description may be incorporated into the claims via judicious construction of the claim language. The patent in question (EP2898704) related to a hearing aid that could be worn for several months or years without being taken out, and a method of manufacturing hearing aids. The problem to be solved by an "extended wear" hearing aid of this type was how to protect the hearing aid's electronics from prolonged exposure to ear fluids. The patent was opposed for lack of inventive step.

The Patentee's defence relied upon a claim construction based on the description of the patent. The granted claim specified a method of manufacturing a hearing aid comprising encapsulating the electronic module. The Patentee argued that this encapsulating step would necessarily lead to a reduction in the chance of moisture reaching the electronics of the device, and that the prior art did not disclose such a step. In support of their claim interpretation the Patentee pointed to passages in the description of the patent stating that the position of the electronics module in the hull of the device "reduced the chance of moisture breaching the capsulation". 

The Board of Appeal was not convinced by the Patentee's arguments. The Board of Appeal argued that the passages of the description cited by the Patentee could not change the interpretation of the claim Particularly, the Board of Appeal dismissed an approach to claim interpretation that incorporated limitations from the description, finding that 'a skilled reader of a patent claim would, for many reasons, interpret the claims based essentially on their own merits [...] This is because the "subject-matter of the European patent" (cf. Article 100(a) EPC) is defined by the claims and only by them'

The Board of Appeal also cited with approval the reasoning from the Boeing catastrophic comma loss case (T 1127/16IPKat). In Boeing, the Board of Appeal found that it was not possible for the patentee to have recourse to the description in order to overcome an added matter objection resulting from the loss of a single comma from the claims. The Board of Appeal particularly found in Boeing that the description could not be used to change the meaning of otherwise clear language in the claims. The Board of Appeal in the present case agreed with this reasoning, finding that "when interpreting the claims, the description and drawings cannot be relied on as a sort of fall-back or supplementary-guidance tool for filling up gaps or for resolving inconsistencies in a claim to the patent proprietor's advantage". 

The appeal was therefore set aside and the patent revoked. Intrestestly, the Patentee did not seek to rescue the patent by incorporating the functional limitation into the claims. 

Final thoughts

T 1924/20 is yet another Board of Appeal decision to add to the pile of recent case law finding against a role for the description in claim interpretation (see also T 0821/20). In all of these cases, the decisions have gone against Patentees arguing for a different interpretation of the claims based on the description in order to overcome an added matter or inventive step objection. The EPO has thus taken a hard line against the particular use of the description to narrow the meaning of the claim language. It will be interesting to see whether in infringement actions, a similarly hard line will be taken against the attempts of alleged infringers to narrow the claims in arguments of non-infringement. 

Interestingly, T 1924/20 also refers to the other hot topic at the EPO at the moment, plausibility (G2/21IPKat). This will be discussed in a second IPKat post. Stay tuned!

Further reading

Claim interpretation

Description amendments

Construing the claims to include technical effects mentioned in the description (T 1924/20) Construing the claims to include technical effects mentioned in the description (T 1924/20) Reviewed by Rose Hughes on Monday, April 10, 2023 Rating: 5


  1. This appears to be going way belong simple use of the descrption to aid claim interpretation and is an attempt to rely on features that should actually be included in the claims. I don't believe it assists aither side in the argument over amendment of the description to be in accordance with the claims.

  2. Rose, I have my doubts whether the EBA would be able to deliver a sensible answer were it to be posed questions relating to adaptation of the description. This is because, within the EPO, there appears to me to be an institutional inability to analyse the situation logically.

    As an alternative approach, may I suggest sending the following multiple choice questionnaire to those responsible for drafting the EPO's Guidelines? (Where all of the following statements must be answered with "Agree", "Disagree" or "Other", and where the latter answer must be accompanied by a detailed explanation.)

    1. If the wording of a claim conveys a clear meaning to a person skilled in the art, it is not permissible in proceedings before the EPO to rely upon a disclosure of the description to afford a different meaning to the wording of that claim.
    2. During examination proceedings, neither Article 69 EPC nor the Protocol to that Article shall be used to determine the meaning conveyed by the wording of the claims.
    3. During examination proceedings, it is not necessary for the ED to provide the applicant with a detailed explanation of its understanding of the meaning conveyed by the wording of the claims.
    4. In proceedings before the EPO, a claim lacks clarity under Article 84 EPC if its wording conveys a clear meaning to a person skilled in the art but a disclosure of the description affords a different meaning to that wording.
    5. If a lack of clarity arises for the reasons set out in statement 4, it is not necessary for the ED to explain precisely why the disclosure of the description renders the wording of the claims unclear.
    6. The claims of an application lack support under Article 84 EPC if the description discloses subject matter that is inconsistent with the invention defined in the claims (which subject matter is not clearly indicated as not being the invention according to the claims).
    7. If a lack of support arises for the reasons set out in statement 6, it is not necessary for the ED to explain precisely why the disclosure of the description is inconsistent with its interpretation of the meaning conveyed by the wording of the claims.
    8. For determining the extent of protection afforded by the wording of the claims of a granted patent, the "description" mentioned in Article 69 EPC (and the Protocol thereto) is the description of the patent as granted.
    9. In view of statement 8, determination of the extent of protection conferred by the claims of a granted patent shall, or at least may, take into account amendments to the description made during prosecution, especially amendments indicating that certain subject matter is not the invention according to the claims.

    I would fully expect the authors of the GL to respond with "Agree" to all of the above statements. However, I would hope that a few dots might be joined by:
    - considering various statements together (such as 2, 6, and 9);
    - comparing and contrasting different statements (such as 1 and 4); and
    - assessing whether other statements (such as 3 and 7) point to a need for Article 84 EPC objections to be fully reasoned (as opposed to vague and/or purely hypothetical).

    Of course, this is the EPO that we are talking about, and so I will not hold my breath waiting for the dots to be joined.

  3. Proof of the Pudding, perhaps you are being a little but unfair to the EPO. Language itself is complicated and the EPO cannot fix that. Imagine how your points would apply to interpreting an independent claim in view of the dependent claims, or interpreting the claim language in view of the use of that language in the closest prior art or in prior art documents cited in the description. A specific meaning emerges only in a specific context and situation (e.g. in view of a cited document relevant to validity, or a possible infringement). Some sort of absolute meaning relevant to all contexts and situations is very difficult to arrive it, even in a 9 point test

    1. Santa, well that is precisely the point that I am trying to make! So having reached the same conclusion, and in view of statements 8 and 9 above, do you still believe it is reasonable for the EPO to demand that applicants make (potentially binding) statements as to which disclosures of the description are NOT the invention according to the claims ... whose scope has neither been methodically determined nor explained to the applicant?

  4. Thanks Proof of the Pudding. Completely agree your point is valid, but you are shifting the burden to third parties (who I often need to advise on FTO). I am not saying the EPO is perfect, but necessarily they must balance the applicant's needs versus third party needs. Your list of 9 points are all very good questions, but, respectfully, they are pro-applicant. I too find amending the description frustrating and potentially dangerous, but I can also see the other side of the argument and the surprising importance the description can have in litigation. There is also a good side to what the EPO is trying to do, although perhaps they are doing it in a disjointed way. My intention is not to disagree with you, but just to give another view on this quite important issue.

    1. Santa, the viewpoint of third parties is indeed important. I share your pain when it comes to determining FTO, especially in view of the UKSC's case law on equivalents.

      However, even if the UKSC's decision could be viewed as having swung the pendulum too far in favour of patentees, this does not even remotely justify what appears to be an extreme overreaction that swings the pendulum too far in the other direction. That is, it is perfectly possible for there to be serious problems with both the case law on equivalents and the EPO's practice on adaptation of the description. Remember, two wrongs do not make a right.

      There are several reasons why I see the EPO's practice as an extreme and unjustified overreaction.

      Firstly, it is simply not the EPO's business to police the determination (by national courts) of extent of protection. Indeed, it is an overreach for them to even try.

      Secondly, the EPO's practice risks achieving results that run directly contrary to the principles set out in the Protocol to Article 69 EPC. That is, they risk limiting the scope of protection to the "strict, literal meaning of the wording used in the claims", and possibly even to a narrower scope that that, depending upon how good a job the ED has done with interpreting the language of the claims.

      Thirdly, if there are problems with the jurisprudence of national courts, then the best way of addressing this would either be through dialogue with those courts or through new legislation. Frankly, attempting to "fix" the case law problem through perverting both the EPO's practice and its mission is both lazy and undemocratic.

      I think that it should be perfectly possible to fix the current case law problems by coming up with a solution that strikes an acceptable balance between the various competing interests. What the EPO has dreamed up is most definitely not such a balance.

    2. Santa, for the record, I disagree with your characterisation of my statements as being "pro-applicant".

      To be sure, they address issues that will be of concern to applicants. Nevertheless, the statements in themselves are neutral, in that they merely aim to determine the manner in which, in practice, the law is interpreted by the EPO.

      Moreover, it is only if one would respond with "Agree" to both of statements 8 and 9 that one might think that any of the other statements are of relevance to FTO for third parties. Indeed, by your later reference to "the surprising importance the description can have in litigation", it seems to me that this is indeed your position. Your reluctance to address the problems highlighted by statements 1 to 7 therefore suggests to me that you are happy with the results of the EPO's practice, even though those results might be achieved through highly questionable means.

  5. Given the potency of E1 as an attack on validity, and the tortuous Art 56 EPC reasoning of the Board, my thought is that this case might have turned out much more happily for the patent owner had the drafter of the patent application first studied the disclosure of E1 and discussed it with the inventor before setting pen to paper, for then the technical effects and the OTP relative to E1 would have been different, and more persuasive, in the application as filed.

    After all, it is not at all plausible to put forward as an invention the mere potting of circuitry in order to protect it from ambient humidity.

    Curious too is how the EPO failed to cite E1 in its search report. After all, E1 (73 pages of it) went on to issue as EP-B1-1214337.

    1. Dear Max Drei,

      Your comment is certainly interesting, but it is not sure at all whether the applicant knew of E1 when the application was drafted.

      In the description as filed, there is no background art mentioned at all.

      In the patent, D1=WO-A1-02/03757 (X,Y in the ISR) was mentioned as prior art.

      D1 supported a novelty objection at the beginning of examination. During examination, the ED added D5=WO-A1-00/53094 to raise an objection of inventive step with D1 as CPA. With new claims a patent was then granted.

      D5 can be found when comparing the documents in the ISR with those quoted on the front page of the patent.

      As the examiner found an X,Y document as well as D2=US-A1- 2004 252 854 (Y), D3=WO-A1-2009/138895 (A) and D4=EP-A1- 0 026 247 (Y,A), it is most probable that the examiner stopped the search. How D5 came into the procedure cannot be determined. It could well come from another member of the ED.

      There was thus no chance for the ED to examine the application with E1 as prior art.

      The patent was maintained in amended form and the board considered that claim1 as maintained was lacking IS over E1 on the basis of partial problems. It is difficult to follow you when you consider the reasoning of the Board under Art 56 to be “tortuous”.

      When looking at published decisions of the BA following oppositions it is noticeable to see that in nearly 90% of the cases the opponents bring forward patent literature which was available in the search files of the EPO. Even Art 54(3) prior art, sometimes from the same inventor.

      It is also noticeable that in most than half the cases the decision of the OD, whatever it might be, is set aside by a BA.

      EP-B1-1214337 should read EP-B1-1314337.

  6. Rather than discussing at length whether the description should be adapted to the claims before grant or maintenance in amended form, it seems better to clarify the use of the description under Art 69 and its protocol as we are in presence of two diverging lines of case law.

    According to the first line of case law, Art 69 and its protocol have to be taken into account during prosecution at the EPO, is represented by T 1473/19 which referred to T 1167/13 and T 2773/18. This line of case law goes back to T 16/87.

    According to the second line of case law, Art 69 and its protocol should not be taken into account during prosecution at the EPO, is represented by T 169/20 and T 821/20, the latter referring to T169/20 and T 1127/16.
    According to T 1279/04, confirmed by T 1778/17, application of the principles of claim interpretation as laid down in Art 69 and the Protocol is to be limited to the determination of the extent of protection which was primarily of concern in infringement proceedings or in opposition under Art 123(3).
    According this second line of case law, there is no justification for relying on the description to restrict the scope of the claim by excluding interpretations which are both reasonable and technically sensible in the technical context of the patent.

    In order to clarify the situation it would be interesting to hear the EBA on the following questions:

    1) Should, in procedures before the EPO Art 69 and its protocol exclusively be used when determining the extent of protection under Art 123(3)?

    2) Can Art 69 and its protocol be used
    - when determining whether a claim
    - contains added subject-matter under Art 123(2) or
    - lacks novelty
    - to assess inventive step, for instance by construing the claims to incorporate a functional effect from the description

    3) If the answer to question 2 is positive which conditions should apply?

    1. Agreed. But Question 1 is for me not free from ambiguity, I might prefer:

      1) Can it ever be legitimate at the EPO to invoke Art 69 EPC and its Protocol for any purpose other than an enquiry into the extent of protection under Art 123(3) EPC? If so, and in particular:

      Every jurisdiction pays lip service to the theory of construing a patent just like any other document, the reader being mindful of the desirability of achieving internal consistency, including interpreting the claim in the context of the description. This new Decision makes a thoughtful attempt to spell out what that means, in practice. But its "sort of fall-back" formulation to define the role of the description strikes me as not much better than "hand waving" and leaves me less than fully convinced. But who can do better, I wonder.

      What about that old US formulation "insolubly ambiguous"? If the claim is that, then it is permissible to turn to the description to resolve the ambiguity. Otherwise, not.

      For example, who remembers the notorious CAFC case Chef America, with its claim to baking dough to 400°F (resulting in slabs of charcoal instead of loaves of bread). Intended, of course, and evident from the description, was baking with the oven set at 400°F. But the claim was clear and down it went, much to the chagrin of the owner and their patent attorney. Also in the USA there is a nice case that turned on an "Oxford comma" so it is not exclusively the EPO that goes in for "catastrophic comma" cases.

    2. Dear Max Drei,

      No problem if you find your formulation of question 1 better.

      I would however refrain using in a referral to the EBA an expression stemming from the US.

      I would however like a reply not resembling that given in G 2/21 (plausibility) which does not really help.

    3. Ganz kurz, Daniel. My suggested text for Question 1 runs to two lines only. The self-indulgent remainder of my post was not intended to be part of the Question. I regret that my IT skills fall short of making my posts clear for readers.

    4. I wondered why my bread was black, dry and disintegrated when touched. That'll teach me for believing the claims of a patent can stand on their own without any description. None of my fellow examiners have been able to make the bread either; I wonder if they have the same problem.

    5. Dear Max Drei,

      No problem. It was all clear to me!

      Your proposal for the question was clearly to be distinguished from the rest.

      You further brought in some interesting considerations and I felt I could comment.

    6. @DXThomas
      Regarding the use of Article 69, the divide between the BOAs must not be exaggerated , and I cannot agree with your presentation.
      Referring to the case law of the BOAs point 6.3.2, the prevailing position is fairly clearly that it is outside the EPO’s remit to apply article 69, only courts are competent for that. The only case where the EPO must apply article 69 is to assess compliance of post-grant amendments with article 123(3). Along this line, the EPO is not supposed to apply article 69 during examination. And if it did, this would in my view entail considerable confusion.
      Recent decisions which set out the interpretation rule applicable to the claims during examination are consistent with this line.
      T 2502/19 of 19 December 2022 (Reason 2.2): “…the claims should be taken by themselves, i.e. without relying on the description and drawings, and tested against the broadest possible or objectively reasonable construction which would occur to the skilled reader. This is because Article 84 EPC stipulates that the matter for which protection is sought is defined by the claims. It does not require to rely on any other part of the application documents.“
      The Board’s statement clearly distinguishes the context of examination, focused

      on the subject matter for which protection is sought, defined by the claims, from the post-grant context to which article 69 applies. In the context of examination, the description must not be relied upon to interpret the claims, especially the description cannot be relied upon to « read » into the claims a feature disclosed in the description as a limiting feature. This do
      T 1553/19 of 28 october 2022 (catchword) : « The normal rule of claim construction of reading a feature specified in a claim in its broadest technically meaningful sense corresponds to determining the broadest scope encompassed by the subject-matter being claimed according to a technically sensible reading. In the case of a feature defined in a positive manner, which imposes the presence of a specific element, this is effectively achieved by giving to the element in question its broadest technically sensible meaning. »
      If the question arises of whether disclosed but unclaimed features can be taken into account, it is in my experience because the EDs do not always require the applicant to include in the claims the feature(s) relied upon by the applicant to overcome the objection. When applicant’s reliance on an unclaimed feature is essential to convince the ED to withdraw the objection, the ED should make their acceptance conditional on the amendment of the claim. Failure to do so is a serious quality issue which should be taken care of by the EPO management.

    7. @ F. Hagel

      That you do not agree with some of my positions is nothing new under the sun. But to claim that I exaggerate goes a trifle too far and is actually not correct.

      In view of the diverging case law I have presented when I have introduced a possible referral, it is manifest that some boards do not limit the application of Art 69 and its protocol to assess compliance with Art 123(3) in opposition proceedings.

      Using Art 69 and its protocol goes back, inter alia, to T 16/87. It is therefore noticeable that some boards would, in sense, like to bring T 16/87 back to life and see Art 69 and its protocol applied in general in proceedings before the EPO. One further recent example is T 2475/18 which I have commented together with T 1473/19. Already there I brought in a proposal for a referral. In T 1473/19, Reasons 3.7-3.9, the board explicitly disagreed with the statements in T 1279/04, and hence with T 30/17, both representative of the second line of case law.

      The decisions you quote, T 2502/19 and T 1553/19, belong to what I would call the second line of case law. They do however not render moot the first line of case law. I would add T 821/20.

      Whatever you might think, there are clearly two lines of case law and it appears important, at least to me, but I know that I am not the only one, that the situation is clarified by the EBA.

      If Art 69 and its protocol are used in assessing the conformity of a claim with Art 123(2), there is a real danger that the whole construction of case law of the EBA in matter of novelty/added matter is becoming obsolete. It is noticeable that neither G 1/03 nor G 2/10 mention Art 69. Art 69 is mentioned, but only in passing, in G 1/16.

      Systematically interpreting the claims in the light of the description actually corresponds to the practice of the German Federal Court (BGH). In X ZR 161/12 and the preceding decisions the GFC considered that a patent is not systematically to be revoked if a claim contains added matter. The added matter is however not to be taken into account when deciding on N or IS. In a more recent decision X ZR 158/18, the GFC seems to be more aligned with the position of the EBA.

      When you discuss “whether disclosed but unclaimed features can be taken into account” it is manifest that you want indirectly to bring back the question of the adaptation of the description. Your position on this topic is as known and clear as mine.

      I can agree with you that, if patentability depends on a feature which is not claimed, this feature should be added into the claim. But this does not withhold the applicant/proprietor to make clear what is claimed or not.

  7. "It will be interesting to see whether in infringement actions, a similarly hard line will be taken against the attempts of alleged infringers to narrow the claims in arguments of non-infringement."

    Interesting for sure but since when did the EPO ever concern itself with infringement or real world applications of the patents it grants (or doesn't).

  8. Patent practitioners seem to believe jurisprudence theory does not apply to them and patent laws. However there is a wider context, and in that context there is acceptance of the need for uncertainty in the system in order for justice to be done. More laws and more case law are not always the solution, see:
    The existence of uncertainty in the use of the description or Art 69 or the Protocol, or the defining of the technical effect also makes it more likely justice will be done in litigation

    1. @Curveball
      Whether there is a need for uncertainty is an intriguing question. I would say it is in the interest of a patentee if third parties are kept in doubt as their freedom, since the prospect of a legal dispute has a chilling effect on potential investment decisions of third parties. In any event, uncertainty is a fact of life in patent matters for many reasons.
      First, at the drafting stage, it is almost automatic for applicants and patent lawers to try to obtain the broadest possible scope. This implies the use of very general language, which entails uncertainties as to their meaning. Second, the search of prior art can never be exhaustive. Even assuming the patent office has thoroughly completed the search, they may have missed a relevant document, and be unaware of non-patent publications, as clear from the prior art cited in third party observations and opposition proceedings. Add to that other issues, such as the scant attention paid by EDs to the sufficiency issue.

  9. Francis Hagel, below I have provided paragraphs 46 to 48 of the lecture that I referred to. You will see that it discusses all the factors that a judge must take into account, and a key one of these is 'justice' for all concerned. None of the above comments places importance on this when looking at the issue of what the description needs to say. It is important to see that justice might need to be achieved at the expense of certainty.
    46. Only one thing is therefore certain. It is that, while as much of it as possible
    is desirable, certainty is not the ultimate or wholly achievable aim of the law.
    The answer to my question must be as indefinite as Lord Brown’s was last
    year. The judicial role often involves the identification, evaluation and
    application of fundamental societal principles, with all the room for
    disagreement that this involves. These principles are not or not necessarily
    the utilitarian principles that Bentham advocated. His thinking remarkably
    ignores the propensity of majorities to overlook the interests of minorities.
    Judges have a special role to protect unpopular interests and the interests of
    the unpopular. The identification, evaluation and weighing of principles
    which quite often pull in different directions is of the essence of judging, not
    only when shaping the common law but also when interpreting statute law.
    47.That necessarily introduces an element of uncertainty into the law. One
    person’s certainty is another’s doubt, one person’s preference is rejected by
    another. We no longer possess the same confidence or faith that led to the
    natural law thinking of the 17th and earlier centuries. But we live in a liberal
    democracy, and, unless we have, and judges seek to identity and reflect,
    some fundamental societal values, the law would be neutered rather than
    neutral, and it would be unclear what if any stance it should take on any
    number of issues. That would be an abrogation of role. Oliver Wendell
    Holmes said, much more pithily than I, in The Path of the Law, that
    “certainty generally is illusion, and repose is not the destiny of man.”
    48.It cannot of course be for each judge to identify and apply his or her entirely
    independent value system. Precedent, consistency, analogy and above all an
    appreciation of the limits of the judicial as opposed to the legislative role all
    continue to serve as important controls or restraints. The collegial aspect of
    legal practice can also instil common standards – so long as it is not at the
    expense of diversity of all kinds at every professional level – though that is
    another theme. Although the law is not a science, it is a disciplined system to
    which (as Sir Edward Coke saw) judges must be loyal.

  10. Forgive me if this has already been addressed, but I am wondering whether a feature in claim 1 with a prima facie narrow meaning could be given a broader meaning when interpreted in light of the description? I have a specific case in mind, where claim 1 refers to a "Boolean input". On the face of it, this would mean either true or false, 1 or 0. The description, however, makes it clear that this is actually intended to be much broader, covering any input string. How should an opposition division construe the claim feature? Narrowly (and therefore possibly novel) or broadly (and therefore lacking novelty)?


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