1.3. Maßstab für die Beurteilung der Einhaltung von Artikel 123 (2) EPÜ

In T 873/23 claim 1 as granted was amended with respect to claim 1 as originally filed inter alia by Feature 1.5x, specifying that, for an electric coil cooktop and an electric glass ceramic cooktop, the control device was configured to control the power level of the cooktop "by turning the heating element continuously on and off". It was common ground that there was no literal basis for "continuously" in the context of "turning the heating element on and off" in the application as filed. However, the board observed that there were other occurrences of the term "continuously" in the description (both as filed and as granted) and in claim 1 as granted in the context of monitoring/sensing the temperature and calculating a rate of change of the sensed temperature. The parties agreed that, according to the patent, in these occurrences "continuously" meant "periodically", albeit with different time periods for monitoring and calculating.

The board agreed in principle with the "two-step approach" for the assessment of added matter set out in the Catchword of T 367/20. The patent claims first had to be interpreted in order to determine the subject-matter they contained after the amendment. They were interpreted in line with G 1/24, which states, in the context of assessing the "patentability of an invention under Articles 52 to 57", that the claims are the starting point and the basis for the assessment, and the description and drawings are always to be consulted to interpret the claims. The board considered this to be true not only for the question of "patentability of an invention under Articles 52 to 57" but also for the issue of Art. 123(2) EPC. In a second step, it had to be assessed whether the subject-matter of the amended claim contained subject-matter which extended beyond the content of the application as filed. In this regard, in accordance with G 2/10, the decisive factor was whether the skilled person was presented with new technical information after the amendment..

The board disagreed with the two interpretations of Feature 1.5x submitted by the appellant (patent proprietor). The board considered that the only convincing interpretation of the expression "by turning the heating element continuously on and off" was that of periodically turning the heating element on and off (at fixed intervals) as submitted by the respondent, which included pulse-width modulation of the heating element in accordance with a predetermined duty cycle. In reply to the appellant’s argument that this interpretation "was not in line with the disclosure in the patent", the board explained that, according to T 367/20, a claim feature had to be interpreted not in isolation but in the context of the whole document it formed part of. This was, however, to be done by taking due account of the primacy of the claims (see also T 1473/19). This was also in line with G 1/24, which states that the "claims are the starting point and the basis" (see also UPC_CoA_335/2023, second Headnote, according to which the claims were the "decisive basis").

The board observed that the application as filed disclosed embodiments in which the heating element was controlled on the basis of a duty cycle and was thus "continuously" turned on and off. However, even in the algorithm using duty cycles, different duty cycles and phases of keeping the heating element "on" for a specific period of time were employed. The heating element was thus not always "periodically" turned on and off, and the "continuity" of the duty cycle was interrupted under certain conditions. As claim 1 as granted did not include these more specific aspects of the power control for the electric glass ceramic cooktop of the application as filed, and as the application as filed did not disclose a periodicity throughout the algorithm, the amendment in Feature 1.5x was at least an unallowable intermediate generalisation of the original disclosure. Moreover, the application as originally filed did not contain a corresponding disclosure (power control algorithm based on a duty cycle) for the electric coil cooktop (Feature 1.5a). Accordingly, the combination of Feature 1.5x with Feature 1.5a extended beyond the content of the application as filed..

The maintenance of the patent as granted according to the main request was thus prejudiced by the ground of opposition under Art. 100(c) EPC. Since none of the claim requests was allowable, the appeal was dismissed.

In T 405/24 the board agreed with the opposition division and the respondents that granted claim 1 contained added subject-matter. Feature 1.7 bore no limitation in respect of the type of "filtered packets" being "routed" to the "proxy system".

The appellant argued that "routing filtered packets to a proxy system" in the context of claim 1 was to be broadly construed, i.e. it should not be narrowly interpreted as "network-layer routing" only. Rather, it should include any kind of "sending", "forwarding" or "logging". The unit "RG1" in step #19 of Fig. 3B at the very least "forwarded" to the proxy device "PD1" those packets (comprising encrypted data) which were not "dropped" but "logged". Thus, the skilled person in the field of data communications would have understood that such "forwarding" was providing a basis for the "routing" action of feature 1.7. According to the appellant, if multiple technically sensible interpretations of a certain claim feature existed, the one which was supported by the patent description should prevail.

The board was not persuaded by the appellant’s argument. First, the board considered that even if the Order of G 1/24 (which related to assessing compliance with Art. 52 to 57 EPC only) could be extrapolated to the assessment of compliance with Art. 123(2) EPC, there was no indication in G 1/24 that "consulting" or "referring to" the description and drawings could translate into adopting a claim interpretation which ensured that the disputed feature was originally disclosed and thus necessarily fulfilled Art. 123(2) EPC. Such an approach, which according to the board inherently assumed that there may be only one "correct" interpretation of a claim feature, namely the one derivable from the original description as its intended meaning, would not lead to an objective assessment of compliance with Art. 123(2) EPC. The board did not follow the approach of T 367/20 (for the event of "mutually exclusive" interpretations) nor T 2048/22 (claim ambiguities). Rather, the board relied on the body of case law which holds that all technically reasonable interpretations of a disputed claim feature are to be taken into account when assessing compliance with Art. 123(2) EPC (see e.g. T 945/20, T 470/21, T 2034/21, T 193/22).

Second, even if, for the sake of argument, the "forwarding" of logged packets (comprising encrypted data) to the proxy device "PD1" in step #19 constituted a specific instance of the more general "routing filtered packets to a proxy system", this would still fail to justify the claimed generalisation, which also encompassed, among other things, network-layer routing of filtered packets not being necessarily logged.

Thus, the board concluded that the ground for opposition under Art. 100(c) EPC in conjunction with Art. 123(2) EPC prejudiced the maintenance of the patent as granted. The same objections applied to auxiliary requests 1 to 7 and 9 to 15. Auxiliary requests 8 and 2b were not admitted into the appeal proceedings. Since there were no allowable claim requests on file, the appeal was dismissed.

In T 1535/23 the board observed that the Court of Appeal of the Unified Patent Court ("CoA UPC") in UPC_CoA_382/2024 applied the same test as the EPO to determine whether an amendment extended beyond the content of the application as filed. This test is known as the "gold standard" (see G 2/10).

The issue at stake in both T 1535/23 and UPC_CoA_382/2024 concerned the omission of a feature from a claim in the context of added matter. In T 1535/23 claim 1 of auxiliary request 5 essentially differed from independent claim 19 of the parent application as filed in that the specific surface area contained in independent claim 19 of the parent application as filed had been omitted and instead two characteristics of a powder X-ray diffraction pattern had been added. The board explained that the parent application as filed disclosed that the said specific surface area was an essential feature of the invention. All the independent claims of the parent application as filed required the said specific surface area, either directly or by reference to another independent claim. Furthermore, in the summary of the invention, the parent application as filed referred, in a first broad aspect, to a crystalline free base of palbociclib having the said specific surface area. Therefore, it was clear to the skilled person that the passages of the parent application as filed relied on by the respondent referred to embodiments all having this specific surface area. Hence, the board observed that the parent application as filed comprised no teaching that the specific surface area referred to in independent claim 19 of the parent application as filed was not an essential feature of the invention disclosed which could be omitted to characterise Form A of the freebase of palbociclib. The board concluded that the omission of the specific surface area in claim 1 of auxiliary request 5 added subject-matter beyond the content of the parent application as filed.

In turn, in UPC_CoA_382/2024 independent claim 1 of the patent related to an on-body glucose monitoring device comprising a sensor assembly and an enclosure with an electronics assembly. The point of dispute was whether the omission of an elastomeric sealing member for sealing the coupling between the sensor assembly and the electronics assembly in the wording of this independent claim added subject-matter. The CoA UPC found that even though a need for sealing was described in the application as filed, there was no described advantage or function of the use of the specific elastomeric material now omitted from the claim, other than that it provided sealing. Therefore, the skilled person understood from the application as filed that the exact method of sealing did not contribute to, and was thus not relevant for, the technical teaching of the invention as disclosed in the application as filed. The CoA UPC concluded that the omission of the use of an elastomeric sealing member from claim 1 of the patent did therefore not extend beyond the content of the application as filed.

The board explained that its conclusion in T 1535/23 was not in contradiction with the decision of the CoA UPC in UPC_CoA_382/2024. The fact that the CoA UPC acknowledged that the feature in question could be omitted without extending beyond the content of the application as filed while the board in T 1535/23 reached the opposite conclusion was based on different factual situations rather than on a difference in legal considerations. Both the CoA UPC and the board in T 1535/23, and the EPO in general, apply the same principle (the "gold standard") in judging whether an amendment extends beyond the content of the application as filed.

In T 325/23 the board agreed with the appellant (patent proprietor) that in general there exists no file wrapper estoppel in proceedings under the EPC. A file wrapper estoppel is a concept in US patent law. It refers to the doctrine that the patent proprietor may be estopped from enforcing an interpretation of patent claims that is inconsistent with statements made during the patent prosecution process. This concept does not exist in the EPC. However, the fact that the appellant had argued during the prosecution of the patent application that the limitation "single row" added to claim 1 was made in order to limit the subject-matter of claim 1 against prior-art document D9 which disclosed "multiple rows", could be taken as an indication that a narrow interpretation of the term "single row" was at least not technically unreasonable. It was therefore appropriate, at a later stage of the proceedings, to follow such a narrow interpretation, which had even been adopted by the appellant during earlier proceedings. Such an interpretation did not correspond to a "file wrapper estoppel" because it did not limit the interpretation of a certain feature to what was argued by the then applicant for all future proceedings. Rather, the consideration of such events in the file history was used to determine whether an interpretation was technically reasonable or not, without excluding other interpretations.

The board did not agree with the appellant's assumption that once an interpretation of a feature was determined, it could only be assessed whether this interpretation contravened Art. 100(c) EPC. Other interpretations were, according to the appellant, no longer relevant for the assessment of the admissibility of amendments.

According to settled case law of the Boards of Appeal, all technically reasonable interpretations of an ambiguous claim have to be considered. If one of those interpretations contains matter that extends beyond the content of the application as originally filed, it has to be concluded that there is added subject-matter (CLB, 10th edn. 2022, II.E.1.3.9e)).

In the context of claim interpretation the appellant further argued that a non-specific definition in a claim should be given its broadest technically sensible meaning and referred inter alia to the chapters II.A.6.1 and I.C.4.1 of CLB, 10th edn. 2022. The board disagreed. While it is true that according to these two chapters a non-specific definition in a claim should be given its broadest technically sensible meaning, none of these citations refer to the interpretation of claims in the context of assessing the admissibility of amendments under Art. 100(c) EPC or Art. 123(2) EPC. The board therefore concluded that all technically reasonable interpretations of the disputed feature had to be taken into account for the assessment under Art. 100(c) EPC.

In the case in hand, the disputed feature was feature (h). The board assessed whether the (narrow) interpretation of feature (h), according to which "single row" meant a single connector line, was already encompassed by the content of the application as filed and it concluded that the ground for opposition pursuant to Art. 100(c) EPC prejudiced the maintenance of the patent as granted (main request). The same reasons applied to auxiliary requests IA and IB and I to XXIII.