G 1/24 : Claim Interpretation at the EPO - No Legal Anchor, but a Clear(er?) Path Forward

The Enlarged Board of Appeal’s recent decision in G 1/24 has provided significant clarification regarding the interpretation of claims when assessing the patentability of an invention under the European Patent Convention (EPC). A central issue addressed was the absence of a clear legal basis within the EPC for claim interpretation in the context of patentability assessment.

Article 69 EPC, together with the Protocol on its interpretation, is primarily concerned with the scope of protection in infringement actions before national courts and the Unified Patent Court (UPC). Its wording, legislative history, and placement within the EPC (specifically, Chapter III, which deals with the effects of the European patent and application) all point towards its focus on post-grant enforcement rather than examination or opposition proceedings.

Conversely, Article 84 EPC is a formal provision, stipulating that the claims must be clear, concise, and supported by the description. However, it does not provide substantive guidance on how claims should be interpreted. As the Enlarged Board observed, Article 84 EPC “only sets out an instruction to the drafter of what needs to be in the claims, and an instruction to the EPO to determine whether the claims meet that purpose.” It does not address the interpretative process itself.

Despite this lack of a definitive legal anchor, a substantial body of case law has developed, from which the principles of claim interpretation can be extracted. The Boards of Appeal have consistently treated the claims as the starting point and basis for assessing patentability, but have diverged on the extent to which the description and drawings should be consulted.

The Enlarged Board has now resolved this divergence, holding that the description and any drawings must always be referred to when interpreting the claims, and not only in cases of unclarity or ambiguity of such claims when taken on their own. This approach ensures consistency with the practice of national courts of EPC contracting states and the UPC, which routinely consult the entire patent specification to determine the scope of protection and the meaning of claim terms. The Board emphasised the importance of harmonisation, noting that it would be undesirable for the EPO to adopt an interpretative approach at odds with the tribunals responsible for enforcing its patents.
This decision aligns the EPO’s practice with that of the UPC, as reflected in recent case law, and underscores the necessity for a high-quality examination of claim clarity under Article 84 EPC. Any unclarity should be addressed through amendment, rather than by limiting the interpretative process to the claim language alone.

In summary, while the EPC does not provide a clear legal basis for claim interpretation in the context of patentability, established case law now mandates that the description and drawings are always to be consulted, ensuring a harmonised and comprehensive approach to claim interpretation across the European patent system. 

Compared to other patent offices, the past and present EPO examination practice has given significant weight to claim clarity, frequently requiring claim amendments during prosecution, leading to introducing definitions from the description into the claims to clarify claim wording. In light of the present decision, this EPO practice can be expected to be reinforced. This decision indeed explicitly states that “the correct response to any unclarity in a claim is amendment”. Such reinforced practice could contribute to avoiding or reducing divergences when interpreting claims in the context of infringement or validity proceedings in front of different jurisdictions (national or UPC), thereby increasing legal certainty.