In some cases, more technical details and more than one example were found necessary in order to support claims of a broad scope, for example where the essence of the invention was the achievement of a given technical effect by known techniques in different areas of application and serious doubts existed as to whether this effect could readily be obtained for the whole range of applications claimed, more technical details and more than one example may be required (see T 612/92; T 694/92, OJ 1997, 408; T 187/93 and T 923/92). In T 694/92 incomplete guidance was given. The claimed subject-matter concerned a method for genetically modifying a plant cell. In fact, the board held that the experimental evidence and technical details in the description were not sufficient for the skilled person to reliably achieve, without undue burden, the technical effect of expression in any plant cell of any plant structural gene under the control of any plant promoter. Further cases, where more than one example was required, may be found in this chapter II.C.7.4.

An application may only be objected to for lack of sufficient disclosure if there are serious doubts, substantiated by verifiable facts. The mere fact that a claim is broad is not in itself a ground for considering that the application does not comply with the requirement that it be sufficiently disclosed under Art. 83 EPC (see e.g. T 19/90, OJ 1990, 476; T 612/92, T 309/06 and T 617/07; see also T 351/01, T 21/05, T 1188/06, T 884/06 and T 364/06). In T 19/90 the claimed invention was defined by the incorporation of an activated oncogene sequence into the genome of non-human mammalian animals in general. The examining division refused the application on the grounds that in the light of the differences among different animals, it could not be assumed that the sole example given – mice – could be extended to all other non-human mammalian animals and the claims were thus unrealistically broad. The board disagreed.

However, in T 636/97 it was emphasised that it is a fundamental principle of patent law that a claim can validly cover broad subject-matter, even though the description of the relevant patent does not enable every method of arriving at that subject matter to be carried out. Otherwise no dominant patent could exist, and each developer of a new method of arriving at that subject matter would be free of earlier patents. In T 694/92 (OJ 1997, 408) the board held that, where an invention relates to the actual realisation of a technical effect anticipated at a theoretical level in the prior art, a proper balance must be found between, on the one hand, the actual technical contribution to the state of the art by said invention, and, on the other hand, the terms in which it is claimed, so that, if patent protection is granted, its scope is fair and adequate. The board highlighted the interrelation between the requirements of Art. 84, 83 and 56 EPC 1973. See also T 187/93.