Federal Court of Justice, Decision of 21 October 2010, Xa ZB 14/09 (Angle Measuring Device)

The Federal Court of Justice confirmed that a feature of a patent claim which has not been sufficiently disclosed in the originally filed documents can remain in the claim provided that this constitutes a limitation of the content of the patent application. Such patent would not be considered as invalid on the basis of "added matter". This approach differs from the standpoint of the Enlarged Board of Appeal of the European Patent Office which would revoke the patent in such an "added matter" scenario.

Both the German Patent Act (GPA) and the European Patent Convention (EPC) provide that a patent is invalid if the subject-matter of the claim goes beyond the content of the original application. In such "added matter" scenarios, the subject-matter of the claim can usually be limited during the nullity proceedings so that it is eventually covered by the content of the original application and therefore complies with the legal requirements. In scenarios where such limitation can only be accomplished by deleting the - originally not disclosed - feature from the claim, such deletion would broaden the scope of the patent, which is again inadmissible under the GPA and the EPC. The patent owner is therefore faced with the dilemma that his patent is invalid either under the added matter rule or owing to inadmissible broadening.

In its decision, the Federal Court of Justice again confirmed the practice of the Federal Patent Court according to which a claim feature which has not been sufficiently disclosed in the application can, under certain conditions, remain in the claim without rendering the patent invalid.

The court emphasized that in order for the patent to be valid, the added feature of the patent claim needs to be a limitation of the subject-matter of the patent compared to the invention disclosed in the original patent application. It specified this "limitation" requirement in more detail, stating that the patent would not be maintained if the relevant feature rendered the protected invention into an "aliud", thus an invention different to the one disclosed in the original application. A limiting feature would be considered as an aliud unless it had been disclosed in an actual embodiment of the invention or in a more abstract form in the original application. On the contrary, an (admissible) limitation of the content of the patent application would be given in cases where the added feature made the technical teaching of the patent simply more comprehensible.

Furthermore, the court held, the patent owner did even not need to include an explicit note in the patent specification stating that he will not derive any rights from the (inadmissible) amendment of the claim (which would correspond to the so-called footnote solution of the Federal Patent Court). Such an explicit disclaimer was not conclusive or required by law but it was sufficient that the patent owner would in fact not derive any rights from this inadmissible feature (in particular that this feature would not be apt to be considered for the assessment of the validity of the patent).

The court also mentioned that his solution differed from the view of the Enlarged Board of Appeal of the European Patent Office which would declare the patent invalid even in cases where the added feature limited the scope of the patent. However, the court explicitly stated that this differing solution may lead to unreasonable consequences on the part of the patent owner and was not justified by any public interest, at least from a German law perspective.