The European Patent Office's Enlarged Board of Appeal recently issued a major decision (G3/14) on the issue of the clarity examination of claims in opposition proceedings at the Office.
Lack of clarity of claims (Article 84 European Patent Convention) is not one of the allowable grounds for opposition enumerated in Article 100 EPC. However, where the patent claims have been amended during opposition proceedings, Article101(3) EPC stipulates that the Opposition Division shall examine whether the amended patent fulfils the requirements of the EPC (including the clarity requirement laid down in Article 84 EPC ) and hence assess whether to allow or revoke the patent as amended.
The question of whether the EPO should examine the clarity of claims that have been amended during opposition or appeal proceedings has been raised repeatedly. There have been two diverging lines of case law decisions in this respect.
- The approach taken in decision T301/87 (the "conventional" view), holding that, where claims are amended during opposition proceedings, objections by reason of lack of clarity are not allowed "if such objections do not arise out of the amendments made".
- The approach taken in decisions T1459/05 and T459/09 (the "diverging" view). Decision T 1459/05 held that examination of the clarity of a feature of a granted dependent claim incorporated into a granted independent claim was permissible, especially where that additional feature was critical for differentiation from the prior art but could be regarded as being unclear. Decision T459/09 held that "unrestricted exercise" of the examination power under Article 101(3) EPC was justified where a claim was amended with a technically meaningful feature.
In these circumstances, the Enlarged Board of Appeal was asked for its opinion as to whether examination of the clarity of amended claims was permissible in cases where one or more elements of dependent claims were inserted into an independent claim, and, if so, as to the scope of the clarity examination.
The Enlarged Board's response was that, for purposes of the examination provided for in Article 101(3) EPC, patent claims may be examined for compliance with the requirements of Article 84 EPC only when, and then only to the extent that, the amendment introduces non-compliance with Article 84 EPC.
Furthermore, the Enlarged Board explicitly approved the "conventional line" and disapproved the "diverging line".