Egg carton illustrates how to package inventions for the Unified Patent Court

For those who have not yet familiarized themselves with the Unified Patent Court’s method for assessing inventive step, Court of Appeal decision UPC-COA-0000908/2025 from August 2026 offers a good introduction in a technical field familiar to us all. The patent at issue, EP 2 755 901, concerned an egg carton. The decision shows how carefully the Unified Patent Court reads the patent specification.

The objective problem is formed from the purposes stated in the patent

The description of EP 2 755 901 identifies four principal purposes for the egg carton it presents: 

• to provide clear visual information about the contents of the package, in particular large surfaces for graphical information, 

• to provide reliable machine closing and locking, 

• to provide a packaging unit that can be manufactured as an integrated moulded unit, 

• to provide reliable locking without a traditional locking flap. 

The Court of Appeal refers directly to the description of EP 2 755 901 when, before assessing inventive step, it formulates (in paragraph 87 of the decision) an objective problem with these exact components.  

The patent specification also mentions some additional embodiment-specific advantages, such as anti-bowing effects, increased rigidity from pillow posts, compensation for moulding deformations, egg protection, and other refinements. These do not enter into the objective problem, although they may to some extent fall under the umbrella of those general purposes. 

The important thing to note is that the purposes presented in the introductory part of the specification are the core of the objective problem (see sections 40-45). If the claim is novel, this objective problem provides the framework for assessing whether the claimed solution involves an inventive step. 

How do distinguishing claim features relate to the objective problem?

The technical features of a claim which are not found in the closest prior art are typically called the distinguishing features of the claim in European patent parlance. 

The discussions on claim 1 in the main request (par.92-109) and first (110-114) and second (115-124) auxiliary requests illustrate how the Court treats the distinguishing features.  

The only relevant difference between claim 1 of the main request and GDM1 was the use of a fibrous package material. The Court considered the use of that material to be an obvious choice and did not find that it provided a non-obvious way of achieving the purposes identified in the objective problem. The main request was therefore not allowable. 

Auxiliary Request 1 added a feature directed to the label arrangement, namely that the label covered the locking structures. This feature was clearly connected to one of the purposes repeatedly emphasised in the patent: maximizing the available label area. However, the amendment did not establish a further difference over GDM1. The Court found that GDM1 also taught that the label could be enlarged and could extend downwards over the relevant region of the carton. Auxiliary Request 1 was therefore not allowable. 

Auxiliary Request 2 added the following distinguishing feature: “the nose works as a hook that hooks onto a lower edge of the aperture.” This amendment related directly to the purposes of reliable closing and locking without a traditional locking flap. This time, the Court found neither the claimed hook arrangement nor a sufficient pointer towards it in GDM1. Auxiliary Request 2 therefore introduced a feature that contributed to a stated objective of the invention, but was not suggested by the prior art. In the Court’s overall assessment, claim 1 of Auxiliary Request 2 involved an inventive step. 

This does not mean that the Court considers a claim inventive whenever a distinguishing feature contributes to one of the stated purposes and is absent from the prior art. The Court’s assessment is a broader examination of whether the skilled person would have arrived at the claimed solution. Nevertheless, the three requests illustrate how the technical purposes identified from the patent provide the framework within which that question is considered. 

Conclusion

The introduction to a patent application written today may play a central role many years from now, if inventive step is assessed by the Unified Patent Court. 

The Court will perform a detailed claim analysis and then frame the inventive step discussion with the purposes and technical benefits presented in the application text. If no such statements were explicitly made, then the Court may infer the purpose of the invention from passages which were not meant to cover all embodiments of the invention. 

Applications should therefore explicitly identify the most important technical purposes of the invention and explain how the key technical features of the invention contribute to achieving them. Features that may later provide useful fallback positions should, where possible, be connected to those purposes as well. The patent may then be more likely to withstand inventive-step attacks at the Unified Patent Court.