3.4.3 Prima facie relevance

In T 736/95 (OJ 2001, 191) the ground referred to by the appellant under Art. 100(c) EPC had not been raised in the notice of opposition. The opposition division had decided not to admit the newly submitted ground, without giving the parties any indication that it considered it to be less pertinent. Having regard to G 10/91 (OJ 1993, 420) and G 1/95 (OJ 1996, 615), the board held that the department of first instance at least had to examine whether a fresh ground was relevant and could therefore prejudice maintenance of the patent. Since it did not do so, but based its refusal to admit the ground only on the fact that it had been raised late, the opposition division deprived the appellant of the opportunity to have the relevance of this ground, and thus its admissibility, examined on appeal.

In T 1340/15 the appellant argued that "prima facie" was to be understood as "at first glance" and that the legal question of whether or not the granted claims were covered by the original disclosure of the application (Art. 100(c) EPC) could not be solved prima facie. The board considered that following G 10/91 the opposition division only had to determine if there were, prima facie, clear reasons for considering the issue of added matter. The "prima facie" test was not to be interpreted so narrowly as to mean that it must be possible to definitely conclude "at first glance" that Art. 123(2) EPC was actually infringed. In the case at hand, in view of the evident ambiguity of the language of the relevant passage, the opposition division had a valid reason for admitting the new ground.

In T 1298/15, the board observed that it was established case law that the main criterion to be considered in relation to a late-filed ground of opposition was its prima facie relevance. That the opposition division had not applied any other criteria did not amount to an improper exercise of its discretion. The board ruled out falling back on other criteria set out in Art. 13(1) and (3) RPBA 2007 – as the appellant (opponent) had argued should be done – on the basis that opposition and appeal proceedings were fundamentally and structurally different in nature. See also e.g. T 3077/19 and T 346/16.