National rights of earlier date are not comprised in the state of the art (Art. 54) for the purposes of the EPO examination for patentability. Consequently, a specific search for national rights of earlier date is not made, although any documents found are mentioned in the search report (see B‑VI, 4.2). However, under Art. 139(2), national rights of earlier date can be invoked, after the grant of the European patent, in national proceedings as a ground for revocation. These rights represent exceptions to the uniformity of European substantive patent law. Where national rights exist, therefore, the applicant has a legitimate interest in submitting separate claims to ensure that the patent granted will not be partly revoked in some Contracting States. The filing of separate claims should, however, neither be required nor suggested.
If an applicant produces evidence in examination proceedings of the existence of pertinent national rights of earlier date in a particular designated State, it is appropriate to allow the submission of separate claims for the Contracting State in question (see H‑II, 2.5 and H-II, 2.6). The evidence must be in the form of a printed specification or, where applicable, a copy of the utility model or utility certificate or of the application for it (see Art. 140); this is necessary to prevent unjustified deviation from the unity of the European patent.
The effect of the national right of earlier date is determined by the relevant national provisions. The examiner does not have to decide whether the applicant has, by means of separate claims, limited the scope of his application to the extent required. That is the responsibility of the applicant.
The examiner must check that the separate claims do not contravene Art. 123(2) and that they meet the other requirements of the EPC.
In contrast to European rights of earlier date, national rights of earlier date are not comprised in the state of the art, so there is no justification for a separate description. However, at a suitable point in the preamble to the description, preferably in a separate paragraph following the information pursuant to Rule 42(1)(a), a reference to this situation must be made, for example along the following lines:
"With reference to ... (e.g. earlier application No. ... in ...), the applicant has voluntarily limited the scope of the present application, and submitted separate claims for ... (Contracting State)."