EPC: Interpreting Claim Terms “Holistically” After G 1/24: Description-Based Definition Applied in T 0439/22

In T 0439/22 (Technical Board of Appeal 3.2.01, 11 December 2025) the Board applied the Enlarged Board’s guidance in G 1/24 on claim interpretation. The decision is a practical illustration of how an explicit definition in the description can determine the meaning of a seemingly straightforward term used in the claims. As this case shows, this can have decisive consequences for novelty and for late attempts to “repair” the description on appeal.

Background

The appeal concerned opposition against EP 3 076 804 (heated aerosol-generating article). The only opposition ground pursued was a supposed lack of patentability, in particular novelty over D1 (EP 2 368 449 A1). The dispute focused on feature (c) of claim 1: the aerosol-forming substrate comprises a “gathered sheet” of aerosol-forming material. Crucially, paragraph [0035] of the description contained a definition of that term. One aspect of “gathered sheet” was defined very broadly in that paragraph, while another aspect was defined quite narrowly. The Board was not sure whether it could use that definition in view of divergent case law on this subject.

Therefore, in an earlier interlocutory decision (24 June 2024), the Board referred questions on claim interpretation to the Enlarged Board. After G 1/24 (18 June 2025), in which the Enlarged Board provided guidance, the proceedings resumed. Subsequently, the proprietor filed an auxiliary request deleting paragraph [0035] of the description to change the claim interpretation, if necessary.

Key findings of the decision

Claim interpretation after G 1/24

Relying on G 1/24, the Board rejected a “two-step” methodology in which the claim is first construed in isolation and the description consulted only later (for example if the claim was considered ambiguous). It held that claim interpretation is a unitary process combining reading the claims and consulting the description and drawings. In that context, “consulting”, “referring to”, “using” and “taking into account” the description were treated as synonyms. (Reasons 2.3–2.4).

Meaning of “gathered sheet”: definition in the description taken at face value

Applying the holistic approach, the Board considered that the presence of an express definition indicated that “gathered sheet” did not have such a universally accepted meaning that further explanation was superfluous. It found that the broader aspect of the definition in paragraph [0035] encompassed the commonly accepted meaning (folded/convoluted sheet) but was not restricted to folded sheets and included other forms of transverse constriction. It therefore declined to disregard the broader definition merely because the patent also disclosed a particular manufacturing embodiment (Reasons 3.5.1–3.5.4).

Outcome on novelty and auxiliary request

Using this definition from the description to broaden the scope of the claim in one aspect, the Board concluded that the main request (patent as granted) lacked novelty over D1.

Then, the Board dealt with the admissibility of the sole auxiliary request in which paragraph [0035] was deleted. The Board decided to admit this request into the proceedings under the Board’s discretion, given the referral history and G 1/24’s clarification (Reasons 4.2). However, the Board held that deleting the definition extended the scope of protection contrary to Article 123(3) EPC.

Specifically, the Board reasoned that deleting the definition from the description meant that the narrow aspect thereof was no longer used to interpret the claim. Consequently, “gathered sheet” suddenly encompassed embodiments not covered by the patent as granted (Reasons 5.4–6). The skilled person would take both the broader and the narrower aspects of the definition into account, according to the Board.

The present case differs from other cases applying G 1/24, wherein the Boards decided not to limit the claimed scope based on a narrow definition in the description. In the present case, one definition contained both a broadening aspect, and a narrowing aspect, while in the other cases the description provided a single narrowing definition.

Analysis and implications

T 0439/22 shows that, after G 1/24, Boards may consult the description as an inherent part of claim interpretation, not only if the claim is ambiguous. Where the patent itself provides an explicit definition, the skilled person is expected to apply it “at face value” provided it is technically reasonable and consistent with the overall teaching (Reasons 3.5).

Procedurally, the decision also illustrates the limited utility—and potential risk—of late description amendments in appeal. Here, deleting a definition to avoid an unfavourable claim interpretation led to an Article 123(3) EPC objection and did not rescue the patent.

Conclusion

In T 0439/22, Board 3.2.01 set aside the Opposition Division’s decision and revoked the patent. After interpreting the claims in light of the description, the granted claims lacked novelty. The proprietor’s sole auxiliary request extended the scope of protection, because deleting the definition of “gathered sheet” from the description broadened the claimed scope in one aspect.

Source: Case law | V.O. Patents & Trademarks