The key question is whether, and if so under what conditions, the description and drawings can be used in the application procedure to assess patentability when interpreting a claim and to what extent a patent can serve as its own dictionary.
The referring Board of Appeal explained in the very detailed reasoned interlocutory decision for referral that there are different lines of decision within the EPO. A stricter line provides that in application proceedings, the terms of the patent claims are to be understood and interpreted on their own merits. The description and drawings are either not to be consulted at all or are only to be consulted if there are ambiguities in the understanding of the terms of the claim.
In the case in question, there was a divergence between the meaning of a claim feature according to the general understanding of the skilled person and according to the explanation in the description. The claim would therefore have to be understood differently depending on whether the description was used for interpretation or not. If it had been used, a certain prior art would have been novelty-destroying. If it had not been used, this would not have been the case.
The Board of Appeal pointed out that the infringement courts, but in any case the EPC and the infringement courts of large member states of the EPC (UK, Germany, France) generally use the description of the drawings to interpret the claim features. The German Court of Justice is probably the clearest in this respect, stipulating that an interpretation must always be based on the description of the drawings and that an interpretation is necessary even if a claim feature is supposedly clear. This is because whether the claim feature has a clear meaning can only be known after a proper interpretation based on the description and drawings. The courts in the UK and France take a similar view.
The Enlarged Board of Appeal will therefore have to answer this very fundamental question. It is to be hoped that the Enlarged Board of Appeal will follow the case law of the infringement courts. For systematic reasons, it cannot and must not be the case that a different claim interpretation is applied in application proceedings than in Infringement proceedings. A coherent patent system requires that the same claim interpretation is generally applied in application proceedings, validity proceedings and infringement proceedings. Furthermore, Art. 69 EPC and the Protocol on Interpretation require interpretation on the basis of the description and the drawings, so that it is not to be expected that the infringement courts will change their case law.
