Judgment dated 14th March 2018, I-15 U 49/16

In its judgment dated 14th March 2018 the Düsseldorf Higher Regional Court strengthened the position of defendants invoking prior use rights. The court’s elaborate reasoning may be an important step towards a more balanced evaluation of plaintiffs’ and defendants’ arguments in German patent cases. The court values the substance of the invention over the subtle choice of different claim categories.

Starting point

Defendants in a German patent infringement case may invoke a right of prior use. The patent shall have no effect in respect of a person who, at the time the patent application was filed, had already begun to use the invention in Germany or had made the necessary arrangements for so doing. That person shall be entitled to use the invention for the needs of his or her own business in his or her own workshops or in the workshops of others. This entitlement may be inherited or sold only together with the business.

The prior use right used to be interpreted very narrowly. In practice, it was very difficult to establish. Defendants need to have very clear documentary evidence to convince the court that they were in possession of exactly the same invention before the priority date of the patent and that they made actual arrangements to use the invention (instead of only contemplating it as one of several possible solutions). Whereas the interpretation of the prior use right has traditionally been narrow, the interpretation of the patent claim and of the acts that may amount to an infringement have been broad. In other words: Even though a defendant may have used the patent infringing embodiment before the priority date of the patent, German courts used to find a subtle argument as to why no prior use right existed for the very embodiment or why the prior use right cannot be invoked against the patent at issue.

The Düsseldorf Higher Regional Court Judgment

The Düsseldorf Higher Regional Court recently issued a very well-reasoned judgment ensuring more consistency between the assessment of the infringement situation and the scope of prior use rights.

In the case at hand, the patent application concerned a protective cover for radio equipment. Claim 1 of the patent-in-suit protects a device, namely a protective covering with certain components. Claim 17 protects a method for combining the individual components.

The defendant erected a spherical radome for one of its customers, using both the device and the process claim. In its defence, the defendant relied on a right of prior use.

According to the findings of the Düsseldorf Higher Regional Court, the defendant had already delivered a construction kit for a spherical radome in conformity with the patent-in-suit to a construction company years before the application of the patent-in-suit was filed. The construction company had used the construction kit to assemble a protective covering on the construction site in accordance with the method protected by the patent-in-suit. The Higher Regional Court also found that the construction company was able to assemble the protective covering "easily", that it appeared “sufficiently certain” that the construction company would do so and that the construction kit "in its entirety could only be used in a technically and economically sensible manner in accordance with the patent”.

On this basis, the Higher Regional Court affirmed the defendant’s right of prior use and vacated the first instance decision. The Higher Regional Court held that, within the scope of its right of prior use, the defendant was allowed to move from the supply of construction kits for protective devices to the manufacturing of protective devices in accordance with the patent claim 1.

With regard to the device claim, selling construction kits (not the whole device) was a direct act of prior use. Notably, the court argued that selling the construction kit, i.e. the unassembled components, brought into existence a prior use right against the patent covering the assembled device. According to the court, delivering the construction kit is an act of infringement if the assembly of the protected device at the customer's premises was sufficiently certain and easy to carry out. Taking into account that the delivery of the construction kit qualified as an infringing activity, as a matter of rational reasoning, such delivery of the construction kit prior to the priority date must be sufficient to bring into existence a right of prior use covering the manufacturing of the assembled device itself. This is convincing and consistent.

Moreover, the court argued that, in cases where the prior user used to supply all components for a device and if the assembly of the protected device by the supplied person was sufficiently certain and easy to carry out, the prior use right was not restricted to continuing the supply of the kits but also covered the user switching to manufacturing the protected device him- or herself.

Even more interestingly, the court also held that the defendant may invoke the right of prior use with regards to the method claim, too. The delivery of the kits for use in the protected method (of assembling the radome) was an indirect act of prior use. However, according to the court, such indirect acts of prior use can bring about a right for direct use if the prior user has supplied all components necessary for the application of the patent-protected method to a third party and if the supplied components could only be used in a technically and economically reasonable manner in accordance with the patent. In such cases, the prior use right was not limited (i) to the offering and supplying of the means for applying the protected method but also covered (ii) the use of the protected method itself. According to the court, there is no justification of a different treatment of device and method claims of the patent-in-suit: The method claim did not go beyond or deviate from the device claim but was merely the adaptation of the device claim into the language of a method claim – a well-known attempt to maximize the scope of the patent, which the court did not value. Under such circumstances, the prior user must be able to invoke a direct right of prior use against the method claim, too. Otherwise, the right of prior use covering the device claim would be worthless. In exercising the device claim, the user would inevitably have to perform all the steps of the method claim when manufacturing a protective covering in accordance with the patent. In spite of the prior use right the prior user would not be permitted to do so. The court rightly held that this would not be a satisfactory result.

The Higher Regional Court granted leave to appeal.


The Düsseldorf Higher Regional Court’s decision is based on sound logic and an appropriate weighing of the parties’ rights. It strikes a fair balance between the scope of protection afforded to the patentees based on the actual scope and value of their inventions and the prior users’ trust in their right to continue the use of their inventions. This is good news for defendants in patent infringement cases. There are other complicated issues in patent case, such as questions of patent exhaustion and suspension of infringement cases during pendency of invalidity actions, where German infringement courts have used to lean towards the plaintiffs. Perhaps this decision can serve as a signal to rethink some of those and level some of the systemic disadvantages of defendants in German patent infringement cases.