Restricting Broad Claims in Germany: The Federal Supreme Court's perspective (Blasenfreie Gummibahn - Weite Patentanspruche und Auswahlerfindung)

Abstract

The system of peripheral drafting has prevailed over central claim drafting in the European Patent Organization, the United States and Japan. Patent claims are supposed to be as abstract as possible to cover as much ground literally as possible. This development - while not worrisome as such - has lead to the expected but unwanted result of overbroad claims unintentionally covering items either not invented or part of the prior art. These issues are well-known in equivalency but usually lead to (partial) invalidity in cases of literal claim interpretation. A second side-effect of broad claim language are inventions covering parts of another invention with surprising properties (selection invention), especially in the field of chemistry. Even though the original patent might cover the combination (either literally or by equivalence) the new invention might be a significant, non-obvious step forward. The German Federal Supreme Court had the opportunity to discuss these issues in its decisions Blasenfreie Gummibahn I/II. While the European Patent Office is extremely critical of broad claims, the German Federal Supreme Court noted that broad claims are not invalid as such. However in most cases such inventions will lack non-obviousness unless they can clearly distinguish themselves from prior art. This paper questions the central point of the decision, whether interpretation of patent claims may never be limiting to patent-scope. In cases where the claim is overbroad, but the ambiguous wording can be interpreted reasonably by the court there seems little reason to (partially) avoid the patent. Instead (like with interpretation in general) both extension and restriction must be considered. Using the perspective of a reasonable person skilled in the art is a working method in determining patent scope. If such a person would not read as much into the claim as a non-skilled individual there is no danger to the public. Otherwise the a process the void the patent will quickly turn out to be a process of unnecessarily rewriting and/or clarifying claims which are already sufficiently clear to its intended audience, i.e. persons skilled in the art. As a result it is not proposed to move back to a system of precise claims expanded upon by an effective doctrine of equivalency but instead to apply a restrictive interpretation of claim language wherever a reasonable person skilled in the art would intuitively do so. The doctrine of equivalence and the broad literal claim interpretation practiced in German patent law must be accompanied by an equally efficient system of reasonably eliminating items evidently not meant to be covered.