5.4. Invention to be performed over the whole scope claimed
The disclosure of an invention relating to a composition of matter, a component of which is defined by its function, is not sufficient if the patent discloses only isolated examples but fails to disclose, taking into account if necessary the relevant common general knowledge, any technical concept fit for generalisation which would enable the skilled person to achieve the envisaged result without undue difficulty within the whole ambit of the claim containing the 'functional definition'. Each case has to be decided on the basis of the facts at hand (T 435/91 OJ 1995, 188, Headnote and point 2.2.1 of the Reasons). The board also specified that there cannot, of course, be a clear-cut answer to the question of how many details in a specification are required in order to allow its reduction to practice within the comprehensive whole ambit of the claim, since this question can only be decided on the basis of the facts of each individual case.
Decision T 435/91 (OJ 1995, 188) related to a claim whose composition comprised a component which was defined only by its function; one of claim 1 essential technical features, the "additive" was defined only by its function. It had to be established whether the description disclosed one way of performing the invention or rather a technical concept fit for generalisation which makes available to the skilled person the host of variants encompassed by the "functional" definition of said claim (see point 2.2.1 of the Reasons).
As explained in T 292/85 (OJ 1989, 275), the need for a fair protection governs both the considerations of the scope of claims and of the requirements for sufficient disclosure. Unless variants of components are also embraced in the claims, which are, now or later on, equally suitable to achieve the same effect in a manner which could not have been envisaged without the invention, the protection provided by the patent would be ineffectual. Thus, it is the view of the board that an invention is sufficiently disclosed if at least one way is clearly indicated enabling the skilled person to carry out the invention. Consequently, any non-availability of some particular variants of a functionally defined component feature of the invention is immaterial to sufficiency as long as there are suitable variants known to the skilled person through the disclosure or common general knowledge, which provide the same effect for the invention. The disclosure need not include specific instructions as to how all possible component variants within the functional definition should be obtained (T 292/85, point 3.1.5 of the Reasons).
In relation to variants, T 292/85 is cited and repeated by, for example: T 81/87 (OJ 1990, 250); T 301/87 (OJ 1990, 335, point 4.3 of the Reasons) and T 212/88 (OJ 1992, 28, point 3.3 of the Reasons) with reference to T 281/86; T 238/88 (OJ 1992, 709, point 4.1 of the Reasons); T 60/89 (OJ 1992, 268; in this case, the common general knowledge did not allow any variants to be found); T 19/90 (OJ 1990, 476); T 740/90; T 456/91; T 242/92; T 1173/00 (OJ 2004, 16); T 986/21.
In T 740/90, the opponent invoked decision T 292/85 to support its assertion of insufficient disclosure. The board stated that decision T 292/85 related to an invention of which one component, defined in functional terms, was such that either some particular variants were unavailable or some unspecified variants were unsuitable. The board held that the disclosure was sufficient since the skilled person was aware, owing to the disclosure of the invention or the common general knowledge in their field, of appropriate variants that produced the same effect for the invention. The board in T 292/85 also stated, however, that the disclosure did not need to include specific instructions as to how to obtain all possible component variants within the functional definition.
In T 206/83 (OJ 1987, 5), the disclosure of a method that allowed only some members of the claimed class of chemical compositions to be obtained was not deemed sufficient for the purposes of Art. 83 EPC (decision referred to in T 409/91).
The disclosure of an invention is deemed sufficient if the skilled person can obtain substantially all the embodiments falling within the ambit of the claims (T 409/91).
The criteria for determining if the invention is disclosed in a manner sufficiently clear and complete are applicable to any invention, irrespective of the way in which it is defined. Therefore, it is immaterial whether or not the invention is defined by a functional feature (T 435/91, OJ 1995, 188, point 2.2.1 of the Reasons; T 1121/03, point 3.1 of the Reasons; T 2172/15, reiterated more recently in T 1311/22, for example, which also repeats the provisions applicable to functional features, including the interaction between different aspects, particularly with reference to chapter II.A.3.5.).
The peculiarity of the functional definition of a technical feature resides in the fact that it is defined by means of its effect. That mode of definition comprises an indefinite and abstract host of possible alternatives, which is acceptable as long as all alternatives are available and achieve the desired result; it therefore has to be established whether or not the patent discloses a technical concept fit for generalisation which makes the host of variants encompassed by the functional definition available to the skilled person (T 1121/03 (no technical concept fit for generalisation – undue burden in carrying out the invention over the whole scope claimed – research programme) and T 369/05; T 671/05 (several considerations on the use of functional features); T 2128/13; T 552/22; (includes an overview of the case law on functional features), T 1311/22 (reference also made to the concept of technical contribution)).
A functional definition is acceptable if all alternatives are available and achieve the desired result. For functional definitions of a technical feature, it has to be established whether or not the patent application discloses a technical concept fit for generalisation which made the host of variants encompassed by the functional definition available to the skilled person (T 552/22).
The disclosure of one way of performing an invention is only sufficient if it allows the invention to be performed substantially within the whole range claimed. In other words, sufficiency of disclosure presupposes that the skilled person is able to obtain substantially all embodiments falling within the ambit of a claim. This principle applies to any invention irrespective of the way in which it is defined, be it by way of a functional feature or not (T 2172/15). In T 2172/15 contrary to the respondent's (patent proprietor's) view, there was no concept fit for generalisation.
With respect to a claimed process defined in a functional manner, i.e. by its outcome, the board in T 1051/09 concluded that what was lacking was a generalisable teaching applicable within the scope of the claims, i.e. beyond the specific examples.
The board in T 2038/19 (water absorbent resin particles) stated by explicit reference to principles laid down in T 435/91 (functional definition of a component) that it was established case law that the same principle applied when the claim contained a parametric definition and when the subject-matter could not be expressed only in terms of structural feature.
In T 500/20 the board explained that in claimed inventions that did not involve a range of parameter values or compositions but were directed at a concept expressed in terms of generic structural or functional features of an apparatus or of a method, it was not enough to demonstrate insufficiency to conceive of an example that fell within the terms of the claim that did not work because it did not achieve the claimed effect fully or at all so that therefore the invention would not be sufficiently disclosed across the entire breadth of the claim.
The mere fact that a claim is broad is not in itself a ground for not considering the claimed invention to be sufficiently disclosed (T 19/90 (OJ 1990, 476 point 3.3 of the Reasons), see also as example T 2224/08, T 447/22).
In T 817/11 (cured coatings exhibiting surface enrichment), as the definition of components a) to c) was very broad, the subject-matter defined in granted claim 1 encompassed a huge variety of possible combinations. That all possible combinations of components a) to c) according to granted claim 1, in any amount, necessarily led to surface enrichment was neither credible, nor was it ever argued during the proceedings, during which the appellant (patent proprietor) even agreed that such was not the case. Therefore, it had to be assessed whether the patent in suit had disclosed a technical concept fit for generalisation that made available to the skilled person the specific combinations (out of the many possibilities encompassed by the subject-matter of claim 1) that did lead to surface enrichment. In other words, whether the skilled person would find sufficient guidance for an appropriate selection of components a) to c) in order to prepare, with a good chance of success, a cured coating exhibiting surface enrichment. In view of the broad scope of the claimed subject-matter, it was not enough that the patent had provided at least one way of carrying out the invention or that some combinations would achieve the required surface enrichment. The skilled person wanting to prepare a coating according to granted claim 1 was left with the task of performing an elaborate program in order to find out which combination of a) film forming materials, b) particles, c) surface active agent and which preparation conditions should be used. The conclusion was in line with e.g. T 1121/03 and T 369/05 since the patent did not provide a technical concept fit for generalisation over the whole scope of the claims.
In T 1638/11, sufficiency of disclosure was also objected to by the respondents (opponents) alleging that the excessive broadness of the claim which amounted that the description of the patent in suit did not contain a technical concept fit for generalisation. Thus, as in decisions T 1121/03 and T 369/05, the functional definition given in claim 1 was no more than an invitation to perform a research programme. The board did not agree. T 1121/03 and T 369/05 did not apply. The technical concept was illustrated by a large number of possible alternatives which made it fit for generalisation, and this in itself only on the basis of the structural features of claim 1. The ambiguity of the functional feature was rather a question of Art. 84 EPC.
More technical details and more than one example may be necessary in order to support claims of a broad scope (T 612/92, T 694/92, OJ 1997, 408; T 187/93). This must be decided on a case-by-case basis. In T 694/92 the board held that more than one example might be necessary in order to support claims of a broad scope, in cases where the gist of the claimed invention consisted of the achievement of a given technical effect by known techniques in different areas of application (summarise of contribution T 694/92 in T 354/97). See also T 435/91, cited at the beginning of this chapter II.C.5.4 a) ).
In case T 596/11, having regard to the broad scope of the claim, more technical details and more than one example were necessary in order to sufficiently disclose the claimed invention. In decisions T 792/00 and T 617/07 it was made clear that the disclosure of an invention was only sufficient in the sense of Art. 83 EPC if the skilled person could reasonably expect that substantially all embodiments falling under the claimed invention, which the skilled person would envisage on the basis of the corresponding disclosure and the relevant common general knowledge, could be put into practice. This was not the case here. The argument that the skilled person would use their general knowledge to supplement the information contained in the application, and the reference to decisions T 206/83, T 32/85, T 51/87, T 212/88, T 580/88, T 772/89, T 231/92 and T 818/97 was not persuasive. All these decisions refer to general knowledge which is readily available or to cases where a reference is made in the patent in suit to documents which contain the necessary information or references thereto. This was not the case in the current patent specification. Also these decisions state that no undue burden should be put on the skilled person. The board stated there could be no reasonable expectation in the present case that the broadly claimed mineral materials could be properly dissolved in any acidic aqueous solution, at least not within an appropriate time or in a sufficient amount. The step of dissolving a particulate mineral material in an acidic aqueous solution was central to the invention.