Abstract on Article 084 EPC for the decision T0325/23 of 10.12.2024

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.