5.1. Publications during the priority interval – effect on elements of the European patent application not entitled to priority

As noted by the EPO President in the reasons for the referral in G 3/93 (OJ 1995, 18), on the one hand, it frequently occurs that in subsequent filings new elements and information are added in respect of prior applications of the same applicant and, on the other hand, inventors are often eager to publish the results of their research as soon as possible.

In its ensuing opinion, the Enlarged Board stated that a document published during the priority interval, the technical contents of which correspond to that of the priority document, constitutes prior art citable under Art. 54(2) EPC 1973 against a European patent application claiming that priority, to the extent that such priority is not validly claimed. This also applies if a claim to priority is invalid due to the fact that the priority document and the subsequent European application do not concern the same invention because the European application claims subject-matter not disclosed in the priority document. The Enlarged Board emphasised that the existence of a right of priority depends, inter alia, on the fulfilment of the requirement that the European patent application claiming the right of priority from an earlier application must be "in respect of the same invention" disclosed in the earlier application. Where priority is claimed but cannot be allowed because the essential condition precedent, that the inventions are the same, is not met, there is no right to priority. Consequently, any publication of the contents of a priority document during the priority interval constitutes prior art citable against elements of the European application which are not entitled to priority. See the example in G 9/93; see also e.g. T 594/90, T 961/90, as well as the discussion in T 301/87, OJ 1990, 335.

T 131/99 stressed that in this regard there is no difference between dependent and independent claims (see also T 85/87, and T 127/92, which is summarised in the next section).