Requests for limitation or revocation: Danish law versus the EPC 2000

The entry into force of the European Patent Convention (EPC) 2000 on December 13 2007 has highlighted the different approaches taken by Denmark and the European Union to the re-examination of issued patents.

The EPC 2000 made it possible to file a request for limitation or revocation, but such a request can be filed only by the patent owner. The restricted claims have force in all member states where the patent has issued, with retroactive effect from the filing date of the patent application.

In assessing a request, the European Patent Office (EPO) checks whether: 

• the amended claims constitute a limitation compared to the claims of the patent as issued; 
• they are clear; and 
• their subject matter can be deduced from the application text as originally filed.

The EPO does not assess whether the claims possess novelty and inventive step over any new documents that may have been published or made known to the patent owner since the issuance of the patent, and the patent owner need not give reasons for the limitation of the claims. It is the patent owner’s responsibility to ensure that the claims are suitably restricted over the prior art.

Filing claims with limited scope grants the patent owner the opportunity to adapt the claims if, at a later stage, the patent owner becomes aware of material that was published prior to the filing of the original patent application, but that was not found in the novelty search (eg, in the shape of patents or other literature). In this way, the patent owner may strengthen its patent prior to any legal proceedings.

Therefore, if a patent owner becomes aware of material that may damage the validity of the issued patent or is considering litigation, it should review the claims with a view to determining whether it would be expedient to file limited claims.

In contrast to the rules established by the EPC 2000, the existing Danish rules allow both the patent owner and third parties to ask the Danish patent authority to re-examine an issued patent valid in Denmark. The Danish patent authority forms an opinion based on the grounds alongside the request for re-examination. It assesses, among other things, the novelty and inventive step of the invention; and re-examination may result in the patent being declared invalid.

If cancellation procedures have been initiated before the Danish courts but a decision has not yet been issued, it is not possible to ask the Danish patent authority to re-examine the patent. If legal proceedings are initiated before the Danish courts while a final decision on a re-examination procedure as requested by a third party is pending, the patent authority will suspend re-examination until the court case has concluded. However, if the request is filed by the patent owner, the patent authority will complete its examination irrespective of whether legal proceedings have been initiated, and the prosecution before the courts will presumably be suspended until a re-examination decision has been issued.

The difference in the handling of requests made by the patent owner and by parties is due to the fact that it may be in the interests of a third party to prolong the decision-making process. The reverse applies to the patent owner, which will presumably prefer a prompt decision which will enable it to enforce its rights against third parties.

As requests for limitation made to the EPO can be made only by the patent owner, presumably a Danish court will equate such a request with a request for re-examination filed by the patent owner at the EPO. The EPC 2000 does not require the EPO to suspend the limitation or examination of patents while national legal proceedings take place in regard to those patents. Therefore, it appears that the patent owner may file a request for limitation of a European patent after legal proceedings have been initiated before the national courts and obtain a restricted patent before the court has made its decision in respect of, for example, the validity of the patent.