Any European patent newly granted by an Examining Division of the European Patent Office (EPO) can be challenged to obtain its revocation, or at least its limitation. To this end, the European Patent Convention provides the possibility to file an opposition against the patent. This leads to opposition proceedings, a special inter partes procedure before the EPO, the main aspects of which are presented in this brochure.
Initiating opposition proceedings
Opposition proceedings may be initiated against a European patent within nine months after publication of the mention of its grant. Since no legal interest of the opponent has to be proven, an opposition may be filed by any natural or legal person. Moreover, an opposition may be filed by a "straw man", i.e. a person having no real interest in the outcome of the proceedings but only acting for another - unknown - third person.
Oppositions are filed in reaction to national patent infringement actions. However, due to the relatively low costs, the majority of oppositions are filed as a precautionary means against potentially dangerous patents of competitors.
An opposition is heard in first instance by an Opposition Division of the European Patent Office in Munich, Germany, or The Hague, Netherlands - rarely also in Berlin. After an opposition has been filed, the competent Opposition Division is determined in accordance with the technical field of the case. An Opposition Division generally consists of three technically qualified members with several years of experience in the examination of patents. The Division may be enlarged by a legal member if complex legal questions are to be decided. For example, for taking evidence on an alleged prior public use, a legal member is generally called upon to support the Opposition Division.
Grounds for revocation
A European patent may only be opposed on the grounds that:
the subject-matter of one or more of the laims is not patentable, in particular not new or not inventive; the patent does not disclose the invention in a manner sufficiently clear and com- plete for it to be carried out by a person skilled in the art; and the subject-matter of the patent extends beyond the content of the application as filed. Other grounds of opposition are not admissible. In particular, an opposition may not be based on the grounds that the wording of the claims lacks clarity, or that the claimed invention was "stolen" from the opponent or a third party by the patent proprietor.
The grounds of opposition must be raised by an opponent before the expiry of the opposition period. The introduction of new grounds of opposition after the expiry of the opposition period is subject to certain procedural restrictions. In first instance proceedings, a new ground of opposition may be examined if the Examining Division considers it as prima facie relevant.
Course of first instance proceeding
The first instance opposition proceedings was streamlined with new rules taking effect on July 1, 2016. After expiry of the opposition period, the EPO sets a four months deadline for proprietor to respond to the opposition(s). If considered necessary, the parties are invited to submit further replies within a specified time limit.
Most opposition cases may be expected to be decided in first instance in less than 18 months. During this period, the written exchange of briefs takes place. If requested at least by one party, which is the rule, the Opposition Division summons the parties to oral proceedings. The summons includes a non-binding preliminary opinion...