Art. 2 of the protocol of interpretation of Art. 69 EPC requires that the scope of protection of a patent claim goes beyond its literal meaning by requiring hat:
"For the purpose of determining the extent of
protection conferred by a European patent, due
account shall be taken of any element which is
equivalent to an element specified in the claims."
The practice shows that the national courts of the EPC member states are do not judge in unison what precisely is to be considered to be equivalent in the sense of the protocol of interpretation. However, in any case, teh considrations employed amount to balancing conflicting interests: The patentee strives for broad protection as a fair remuneration for his invention, his competitors want free competition.
Where is the borderline to be drawn to ensure fair protection for the patentee's inventive achievement? How can the borderline be made visible in order to guarantee a sufficient degree of legal certainty?
The BGH has answered these two questions by providing three other questions relating to the claim to be interpreted - the so-called "Schneidmesser" - questions:
1) Does the variant of the claim with the allegedly equivalent element solve the problem underlying the invention by means which have objectively the
same technical effect?
2) Was the person skilled in the art enabled by his or her expertise on the priority date to find the modified means as having the same effect?
3) Are the considerations that the person skilled in the art applies based on the technical teaching of the patent claim?
Whilst the first question is a simple technical quesiton and the second one boils dow to a kind of obviousness analysis, the third one is always the most difficult to answer and a little obscure.
The German Supreme Court (BGH) has now shed some new light on this third question - in the decision "Okklusionsvorrichtung" X ZR 16/09. In the case at issue, the specification had explicitly mentioned several alternatives for a specific feature, whereas only one of these alternatives was claimed. The court ruled that the choice of a specific alternative for achieving a technical effect was one of the considerations constituting the technical teaching of the patent claim and that there is no infringement if the alleged infringer does not make use of these considerations.
As a consequence, the mentioning of non-claimed alternatives in the specification forecloses the patentee form arguing that these alternatives are equivalent.
From a practical point of view, this is problematic because the practice of mentioning many alternatives as possible fallback positions has to be questioned. There will be no problem if the alternatives are mentioned in order to support a broad feature covering all of them. However, the scope of protection might be reduced if the claim is limited to one of the alternatives in the examination procedure. It might be worthwhile considering the deletion of the non-selected alternatives in this case.