In litigation proceedings, a patentee is not legally bound by his argumentation during the previous prosecution or opposition stage. The Higher Regional Court of Duesseldorf reconfirmed this patentee friendly string of case law in a recent judgment (OLG Duesseldorf, judgment of December 20, 2017, I-2 U 39/16 – Smoking Article).

The German patent litigation system is a bifurcated one. The civil courts handling infringement matters are not entitled to decide on the enforced patent’s validity. However, they are also not bound by the claim construction applied by the competent bodies in cancellation proceedings (e.g. the German Federal Patent Court deciding on a nullity action). In consequence, a patentee is not prevented from availing himself of an inconsistent argumentation in cancellation proceedings on the one hand and subsequent or parallel infringement proceedings on the other hand. He may, for example, favor a narrow interpretation of his patent’s claim on the cancellation side, while fighting for a broader interpretation and scope of protection in an infringement action.

Already decades ago, the German Federal Supreme Court greenlighted this freedom of argumentation of the patentee subject only to one exception. The patentee is bound by a declaration made during invalidation proceedings in subsequent litigation if and to the extent that:

-    he disclaimed the specific embodiment contested with the litigation action during the opposition proceedings,

-    the patent survived the opposition due to the patentee’s respective declaration, and

-    the defendant to the infringement action was also a party to these opposition proceedings.

The preconditions of this anyhow rare exception are applied in a restrictive manner by the German civil courts. In its recent judgment of December 20, 2017, the Higher Regional Court of Duesseldorf again denied their fulfillment and confirmed patent infringement. The patent claim at issue concerned a cigarette paper with reduced inflammatory characteristics. Those were achieved by the application of a thin film of material closing the paper’s pores’ to a certain extent. During production, the material forming the thin film had to be applied in a dissolved form (“solution”). In ongoing opposition proceedings, the patentee argued that the term “solution” as comprised by the patent’s claim did not include “suspensions” in order to overcome objections based on prior art related to such suspensions only. In his infringement action, however, he then argued that the defendants’ application of the film material in form of a suspension does not lead outside the scope of protection of his patent. Although the parties to the opposition and the infringement proceedings were identical, the court found that the patentee was not bound by his previous argumentation from the opposition proceedings, since it did not sufficiently clearly show his intent to disclaim use of “suspensions” and that, in addition, no impact of his argumentation on the opposition division’s decision to maintain the patent could be detected.

Practical Impact:

Even without legally binding effect declarations and arguments made by a patentee in cancellation proceedings can be taken into account by the court in infringement proceedings. Consequently, discrepancies in the argumentation should be avoided as effectively as possible. If, in exceptional cases, the application of a double tracked argumentation should become necessary, the patentee should pay particular attention to the wording chosen in the cancellation proceedings. He should especially avoid declarations unambiguously disclaiming such embodiments he might want to contest in infringement proceedings later on.