Functional features or parameters can generate an objection under Art. 83 EPC (enablement) or Art. 84 EPC (clarity) in case of ambiguity of the term. However, the ambiguity of such a term is not, by itself, a reason to deny sufficiency of disclosure. What is decisive for establishing insufficiency is whether the functional feature or parameter is so ill-defined that the skilled person is not able to identify without undue burden the technical measures necessary to solve the underlying problem on the basis of the disclosure as a whole and using common general knowledge.
In a recent decision of April 2014, the Boards of Appeal of the EPO has confirmed an approach of a former decision of the Boards of Appeal to find out whether this condition for insufficiency of disclosure is met (T 2403/11). The approach contains the following four steps:
- Identifying the problem to be solved by the invention in the patent/patent application (not in view of the closest prior art!).
- Determining the relevance of the functional feature/parameter for solving this problem.
- Analysing whether the functional feature/parameter is indeed ambiguous.
- Analysing whether sufficiency of disclosure has to be denied due to this ambiguity, if any, and the relevance of the functional feature/parameter for solving the problem.
In the cited decision, the Boards of Appeal came to the conclusion that the viscosity of a claimed composition is not available as a selection criterion to identify suitable coating compositions that solve the problem underlying the opposed patent in view of its ambiguity. The skilled person has to identify suitable compositions by trial and error. Hence, the patent is nothing more than an invitation to perform a research program (Reasons No. 2.6).