In opinion G 2/98
(OJ 2001, 413) the Enlarged Board of Appeal addressed the whole concept of "the same invention" in Art. 87(1) EPC 1973
. (The relevant provisions were not amended in the EPC 2000 and the principles set out below continue to apply.) In the years preceding the opinion of the Enlarged Board in this case, the boards applied different yardsticks to assess identity of invention between a previous and subsequent application. One was to check whether all the features of the invention claimed in the European patent application were disclosed in the priority document ("novelty test"). In T 311/93
and T 77/97
in particular, boards looking at the validity of priority claims continued to apply the criterion of at least implicit disclosure used for the disclosure test under Art. 123(2) EPC 1973
. Other decisions however followed the principle, developed in "Snackfood" (T 73/88
, OJ 1992, 557), that adding non-essential features which merely limited the scope of protection did not invalidate the priority claim. This latter decision allowed a claim to enjoy priority despite containing an additional feature not disclosed in the earlier application.