Opposition proceedings for European patents

Anyone can file an opposition request against an authorized patent within 9 months from the date of the European patent authorization announcement. The opposition request must be filed with the EPO in Munich, The Hague or Berlin, and the opposition fee must be paid before the opposition period. The EPO's Opposition Chamber is responsible for the opposition procedure and is composed of 3 examiners with technical backgrounds, but only 1 examiner who has participated in the early authorization procedure can be a member, and this member cannot serve as the presiding judge of the Opposition Chamber. After the opposition procedure is over, the patent authorization will either be maintained or modified, or the patent will be revoked. The decision made in the opposition procedure applies to all designated contracting states, and both parties to the objection may appeal to the EPO's Board of Appeal.

Opposition requests can be filed electronically using EPO Online Filing (OLF) or Online Filing 2.0. Notices of opposition can also be filed by fax. A written statement setting out the grounds for opposition must be filed within the period for filing an opposition. Oppositions can only be filed on the following grounds:

• No novelty according to Art 52(1), Art 54, Art 55
• No inventive step according to Art 52(1), Art 56
• According to Art 52(1), Art 57, the invention is not industrially applicable.
• Not an invention according to Art 52(1) and (3)
• Not patentable under Art 53
• Not clear enough or not disclosed enough to enable a person skilled in the art to carry out the invention
• The subject matter of the European patent goes beyond the content of the application filed

Oppositions can be filed even if the European patent has been abandoned or has expired in all designated States. This is because, in this case, the rights acquired with the patent continue to exist until the abandonment or expiration, while claims arising from these rights remain valid after that date.

The opposition applies to all Contracting States in which the European patent has effect. In principle, therefore, the opposition must be filed against all designated States. If an opposition is only filed against some of the designated States, it will be deemed to be filed against all of them.

The effectiveness of oppositions may differ between Contracting States. A patent contains different claims for different Contracting States.

Accelerated process of oppositions: If infringement proceedings relating to a European patent are pending before the Unified Patent Court or a national court of a Contracting State, a party to the opposition proceedings may request accelerated processing. This request may be made at any time. The request for accelerated opposition must be submitted in writing. Furthermore, the European Patent Office will also accelerate the processing of oppositions if the Unified Patent Court, a national court or the competent authority of a Contracting State informs the European Patent Office that infringement or revocation proceedings are pending.

Extension of time for opposition: In opposition proceedings, extensions are generally not allowed. Only in exceptional circumstances with sufficient evidence will a request for an extension of time beyond the normal 4-month period be granted.