Under Art. 90(3) EPC, if the patent application is accorded a date of filing, the EPO examines, in accordance with the Implementing Regulations, whether the following requirements have been satisfied:

- Art. 14 EPC, concerning the language of the patent application (see chapter III.F.1.);

- Art. 78 EPC, concerning the requirements of a European patent application (see in this chapter IV.A.6.1.);

- Art. 81 EPC, concerning the designation of the inventor (see in this chapter IV.A.6.2.);

as well as any requirements laid down in the Implementing Regulations, and, where applicable;

- Art. 88 EPC, concerning claiming priority (see in this chapter IV.A.8.);

- Art. 133 EPC, concerning general principles of representation (see chapter III.V.);

- any other requirement laid down in the Implementing Regulations (see in this chapter IV.A.6.3.).

Under Art. 90(4) EPC, where the EPO notes that there are deficiencies which may be corrected, it shall give the applicant an opportunity to correct them. If any deficiency noted under Art. 90(3) EPC is not corrected, the patent application shall be refused unless the EPC provides a different legal consequence (Art. 90(5) EPC).

In J 18/08 the board stated that Art. 90(5) EPC provides that if any deficiency noted in the examination under paragraph 3 is not corrected, the European patent application shall be refused unless a different legal consequence is provided by the Convention. From this it follows that if an appeal is filed against such a refusal, the board has to examine whether the deficiency noted has been corrected or not. The present case was different from the situation where the non-observance of a time limit automatically leads to the application being deemed to be withdrawn. In such a case the legal consequence automatically ensues when an act required within a specific time limit is not performed, without any decision to be taken concerning the refusal of the application (R. 112 EPC). By contrast, if the application is refused under Art. 90(5) EPC the deficiency on which the decision is based can be corrected at the appeal stage.