First published in BARDEHLE PAGENBERG IP Report 2008-V at www.bardehle.com
Generally, a patent claim may not be interpreted "below" its literal meaning. However, exceptionally, a restrictive interpretation of a patent claim below its literal meaning is justified if the technical result to be achieved by the invention is only achieved by a technical teaching according to such restrictive interpretation.
The plaintiff sued for infringement of three patents relating to a multi-gear hub and change-speed hub, respectively. After having commissioned a court expert, the District Court rejected the complaint based on the court expert's advice. The Court of Appeals, also having consulted a court expert, dismissed the plaintiff's appeal based on the court expert's advice. In the appeal decision, the Munich Appeal Court widely referred to the court expert's opinion without performing its own detailed interpretation of the relevant patent claims by considering the patent specification and drawings. Notably, the court expert's opinion associated technical requirements and restrictions with the claimed multi-gear hub and changespeed hub, respectively, which were not expressly mentioned in the relevant patent claims. The legal appeal of the plaintiff to the Federal Supreme Court was successful. The decision of the Court of Appeals was lifted and the matter was referred back to the Court of Appeals including some guidelines on proper claim construction.
In this context, the Federal Supreme Court had to decide whether at all, and if yes, under which circumstances an interpretation of a patent claim "below" its literal meaning applies.
The Federal Supreme Court found that – exceptionally – a (restrictive) interpretation of the scope of protection of a patent claim "below" its literal meaning applies if the technical result to be achieved by the invention is only achieved by a technical teaching according to such restrictive interpretation. Such restrictive interpretation may be indicated but also rebutted by further patent claims and their features, or by the patent specification and drawings or by objective technical factors derived from the general knowledge of the average person skilled in the art.
In the Federal Supreme Court's opinion, the Court of Appeals did not perform an own evaluation in this respect, but – besides relying on the factual findings – also adopted the court expert's understanding of the relevant patent claims. In this context, the Federal Supreme Court emphasized that the interpretation of a patent claim is purely a legal question which needs to be decided by the court in its own responsibility. The role of a court expert is to advise the court on the relevant technical background and on any relevant facts which may be needed for understanding the technical teaching of the patent and thus for performing a proper legal interpretation of the patent claim. The court may therefore rely on a court expert as far as the technical set of facts is concerned, but may not simply adopt the court expert's understanding of the relevant patent claim without any evaluation of its own. According to the Federal Supreme Court, the claim interpretation by a court expert has just as little priority as the interpretation by the parties of the lawsuit.
With the present decision, the Federal Supreme Court further specified its case law on the interpretation of patent claims, while at the same time emphasizing again the supportive (but not authoritative) role of the court expert which was already established in a series of previous decisions, most of which are originating from the same Munich Appeal Court.
In a first step, the Federal Supreme Court presents the essence of its previous case law by expressly naming the various factors for proper claim construction, such as, for example, the patent specification and drawings, and by explaining that a preferred embodiment does usually not allow for limiting a claim wording describing the invention in general and having a broader literal meaning.
Thus, the Court arrives at the meanwhile established rule that the scope of protection of a patent claim may generally not be interpreted "below" its literal meaning.
In a second step, the Federal Supreme Court explains – and this is the "new" aspect of the present decision – that there can be an exception to this rule, namely if the technical result to be achieved by the invention is only achieved by a technical teaching according to a restrictive interpretation "below" the literal meaning of the patent claim.
In the practice of the German first and second instance infringement courts, patent claims are usually interpreted on the basis of a so-called function-oriented interpretation, i.e. the literal meaning of a claim feature is interpreted in the light of its technical function from the point of view of the average person skilled in the art. Although the present decision is clearly in conformity with this approach, it must be expected that patent infringers will now try even harder to argue that – exceptionally – an interpretation "below" said function-oriented literal meaning is required in the individual case – distinguishing the infringing product from the patent claim. Therefore, the focus of claim construction will be even more on the objective technical results and advantages achieved in the future with the patented teaching in view of the actually claimed subject matter.
© BARDEHLE PAGENBERG; 2008
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