5.4. Invention to be performed over the whole scope claimed
Decisions T 2773/18, T 500/20 and T 1983/19 started a discussion on how far the principles applied to mechanical engineering. These three decisions were specific to the field of mechanical engineering as opposed to the field of chemistry in particular. This sub-section summarises both the approach taken in the case law of the boards of appeal and the discussion of this approach, in particular in T 149/21; T 149/21 has been cited and repeated in numerous decisions since. Given that this case law is relatively new, this edition restates in detail the relevant reasons set out in the cited decisions.
In T 2773/18 (mechanics) the patent concerned a wind turbine with a cooling device using outside air, in particular for marine environments. In support of an alleged lack of sufficient disclosure concerning the expression "upper part of the tower", the appellant (opponent) argued that not only was the claim was not limited to an offshore wind turbine but the dimension of the lower and upper parts was also not limited to a minimum size or height. The scope of claim 1 thus covered embodiments where the inlet was located quite low above sea level and therefore unable to achieve the technical effect of drawing outside air with a low water and salt content. This argument failed to convince the board, not least because it misapplied case law developed in the field of chemistry – for where a claimed invention was in a compositional range or other range of values but the associated effect was perhaps not proven or plausible for large parts of that range – to an invention claimed in the field of mechanics, even though it claimed no ranges. By its very nature, a claim in the field of mechanics, which – often in functional or other generic terms – attempted to capture the essence of some specific machine or mechanical structure (or its operation), was schematic and allowed for some breadth of interpretation. It might be that, on clever construction, subject-matter could be found to be covered by that breadth that might not solve the problem or achieve the desired effect. However, this was normally not an issue of lack of disclosure, but rather of claim construction. Whether the claims, description and figures provided the skilled person with sufficient information to carry out an invention was a purely technical question that was separate from that of what reasonably fell within the ambit of the claim wording. In the board's view, if the skilled person, upon consideration of the entire disclosure and possibly using common general knowledge, could infer what would and what would not work, a claimed invention was sufficiently disclosed, even if a broad construction might also encompass what did not work. In the case in hand, the skilled person would be able to directly recognise and exclude embodiments which obviously would not achieve the effect sought. In particular, the skilled person would disregard an upper part placed much lower than 30 metres above sea level. The board thus confirmed the opposition division's positive assessment of sufficiency (Art. 100(b) EPC).
The board (in mechanics) in T 500/20 (wind turbine) stated that the general argument made in mechanics that the invention would not be sufficiently disclosed across the entire breadth of the claim misapplied an approach developed mainly in the field of chemistry for inventions where a central aspect of the claimed invention was a range of compositions or of parameter values. In claimed inventions that did not involve a range of parameter values or compositions but were directed at a concept expressed in terms of generic structural or functional features of an apparatus or of a method, it was not enough to demonstrate insufficiency to conceive of an example that fell within the terms of the claim that did not work because it did not achieve the claimed effect fully or at all so that therefore the invention would not be sufficiently disclosed across the entire breadth of the claim (see Catchword). The board further specified that to successively argue insufficiency in a case such as this a very high burden of proof applied.
In T 1983/19, the mechanical board dealt with the issue of reproducibility of the invention "across the whole claimed scope" in mechanical engineering. Appellant II (opponent) had argued that the skilled person could not achieve the alleged effect for all variants covered by the claim. The board was not convinced. What mattered was that the patent illustrated to the skilled person one way of performing the invention. The case law developed in particular in the field of chemistry, according to which the invention had to be reproducible over the whole claimed scope, could not be applied to mechanical engineering without making some compromises. Almost every mechanical claim covered countless embodiment examples that were conceivable but unworkable. Yet, this did not mean the invention as such could not be carried out (see also T 2773/18). For example, if it was obvious to any person skilled in the art that slide rings and counterpart rings made of a ceramic material or hard metals could not be deformed by a bellows-like spring means, as argued by appellant II, then the skilled person would simply not use any such slide rings or counterpart rings when putting the invention into practice. However, this did not imply that the skilled person was unable to carry out the invention. The board therefore held that the ground for opposition under Art. 100(b) EPC did not prejudice the maintenance of the patent as granted.
The mere fact that claim is broad is not in itself a ground for not considering the claimed invention sufficiently disclosed (T 447/22). The board in T 447/22 wished to emphasise that objections of insufficiency of disclosure that question whether the invention can be carried out over the entire breadth or the whole range of the claims had their roots in case law that was mainly developed in the field of chemistry for inventions where a central aspect of the claimed invention was a range of compositions or of parameter values (see T 2773/18, T 1983/19, and T 500/20). In the field of mechanics, however, such objections were rarely successful. In the case in hand, the skilled person would readily exclude exotic embodiments that were not used in practice, such as pipes arranged at a very small angle relative to one another, even if these would theoretically fall under the claimed subject-matter.
In T 149/21 (electrical engineering board), the invention related to a method for reducing the energy consumption of a rolling mill installation. The opposition (Art. 100(b) EPC) had been rejected. At the oral proceedings before the board, the respondent (patent proprietor) argued that under the case law of the boards of appeal it was sufficient for the application as originally filed to disclose at least one way of performing the invention in order to satisfy the requirement of Art. 83 EPC. It was thus immaterial whether the claimed scope also covered other "exotic" scenarios. The board agreed that the contested patent detailed at least one way of performing the claimed invention and thus satisfied at least R. 42(1)(e) EPC. According to the established case law of the boards of appeal, however, the claimed invention had to be reproducible over the whole claimed scope. It was thus essential to disclose at least one way of performing the claimed invention, but this was not sufficient to satisfy the requirement of Art. 83 EPC. Moreover, the board emphasised that this case law was not generally limited to the technical field in question, as the same criterion had been confirmed and applied multiple times not just in chemistry but also in the fields of electrical engineering, physics and mechanical engineering. In the board's view, characterising this case law by technical field would be difficult to reconcile simply because the EPC had to be applied in a harmonised way as regards the requirement of reproducibility.
However, the board in T 149/21 did note that recent decisions in mechanical engineering (see T 2773/18, T 500/20 and T 1983/19) had found that the criterion "across the whole claimed scope", which had originated from the field of chemistry, was not necessarily applicable to other technical fields like mechanical engineering. In this regard, it had been pointed out in T 1983/19, for example, that the case law developed in particular in the context of chemistry, according to which the invention had to be reproducible "over the whole claimed scope", could not be carried over to mechanical engineering without making some compromises, since almost every mechanical claim covered countless embodiment examples that were conceivable but unworkable. As per T 1983/19, however, this did not mean that the "invention as such" could not be carried out. Rather, it was sufficient if the patent illustrated to the skilled person just one way of performing the invention. The appellant had also invoked this argument in the case under discussion. However, the board was of the view that while disclosing one way of performing the claimed invention may be sufficient to satisfy the requirement of R. 42(1)(e) EPC, this would not necessarily satisfy Art. 83 EPC. Rather, the case law has it that, on the basis of the contested patent and their common general knowledge, the skilled person specified in said article should be able, across all technical fields, to carry out the claimed invention over the whole scope, i.e. in accordance with all technically feasible interpretations that a skilled reader would consider using objective criteria on the basis of their common general knowledge. In other words, the board found that all "technically sensible" claim interpretations had to be taken into account in the Art. 83 EPC examination, but an interpretation did not necessarily have to meet the requirements of the EPC in order to be considered "technically sensible". The requirement that the disclosure allowed the claimed invention to be put into practice "across its whole scope" was also consistent with the fundamental policy aim that the exclusive right granted by the scope of a patent should always be justified by the actual contribution made by the patent to the art. In the board's view, the case in hand did not constitute an exception in this regard. The contested decision was ultimately reversed and the patent revoked.
In T 174/21, the invention concerned a method of estimating an acoustic transfer quantity by employing a hearing instrument and a hearing instrument therefor. With reference to T 2773/18, the respondent (patent proprietor) expressed some doubts as to the applicability of the "whole range claimed" requirement in the field of audiology. However, the board considered that these doubts were unfounded, referring in this respect to the conclusions drawn in T 149/21.
In T 748/19 (video surveillance), the board was aware of discussions in recent decisions and agreed with T 149/21 that there was no basis in the EPC for applying different standards for compliance with Art. 83 EPC depending on the technical field. The board considered also T 1983/19.