Claim interpretation at EPO vs. UPC

Claim interpretation compared: a closer look at EPO and UPC

As previously reported, the Enlarged Board of Appeal’s decision in G 1/24 has marked a significant restatement of the EPO’s principles on claim construction. It has confirmed that, for the EPO, the starting point for interpreting a patent is always the wording of the claims, which define the invention for the purposes of patentability under Articles 52–57 EPC. Crucially, the Board held that the description and drawings must always be consulted—not only when the claims are ambiguous. For the EPO, this obligation applies even where the claim language seems clear, ensuring that interpretation is rooted in the context provided by the patent as a whole. This approach is inclusive: the description is a constant interpretative tool, and examples given there may influence how a feature in the claim is understood. In practice, the EPO’s method tends to accommodate a broader view of the claim’s meaning, so long as that meaning can be reconciled with the claim wording.

The UPC’s general approach to claim construction is in some respects similar, but has its own procedural and conceptual framing. The Court of Appeal has made clear—most notably in NanoString v. 10x Genomics—that claim construction is a matter of law for the court to decide, not a question delegated to experts. The standard is how the skilled person, in light of the description and drawings, would understand the claim. Like the EPO after G 1/24, the UPC also regards the description and drawings as always relevant. But the court’s role is not to reconcile all embodiments in the description with the claim language; rather, it is to establish the autonomous technical meaning of the claim and assess whether the description supports, contradicts, or leaves that meaning unaffected.

It is in this framework that the recent Agfa decision (UPC CFI 278/2023, Hamburg Local Division) sits. The case concerned a claim to an “achromatic color” base coat. The description listed examples—off-white, pale clay, pale yellow—that might, on a descriptive reading, seem to fall within that category. The court, however, applied the technical meaning of “achromatic color” (wavelength components roughly equal in amount) and concluded that these examples did not meet the definition. They were therefore excluded from the claim’s scope. Agfa demonstrates that while the UPC consults the description as a matter of principle, it will not allow inconsistent description passages to expand the claim’s meaning beyond its clear technical sense.

In contrast, G 1/24 gives the description a more active, shaping role in EPO proceedings, even where the claims appear clear on their face. The contrast is subtle but important:

At the EPO, the description is integrated into the interpretative process for patentability and can influence meaning where possible.
At the UPC, as Agfa shows, the description informs the reading, but the claim wording may ultimately prevail if the two diverge.

This divergence means that the same claim language could, in certain edge cases, be construed more narrowly before the UPC than before the EPO—an outcome that may directly affect both infringement and validity assessments.