Sufficiency of disclosure within the meaning of Art. 83 EPC must be assessed on the basis of the application as a whole – including the description and claims – (see leading decisions T 14/83, OJ 1984, 105; and also T 169/83, OJ 1985, 193) and not of the claims alone (see e.g. T 202/83, T 179/87 of 16 January 1990 date: 1990-01-16, T 435/89, T 82/90, T 126/91). The drawings must be considered as ranking equally with the other elements of the application when considering whether the requirements of Art. 83 EPC (and Art. 84 EPC) have been satisfied (see T 169/83, OJ 1985, 193; T 308/90 and T 818/93).
In T 32/84 (OJ 1986, 9) it was pointed out that the fact that certain elements of an invention essential to its operation were not referred to explicitly either in the claims, or in the relevant portion of the description nor shown in the drawing of the invention as claimed did not necessarily mean that the application did not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art as required by Art. 83 EPC 1973. This decision was cited, inter alia, in T 391/91, T 830/02 and T 25/09.
According to established case law, substantially any embodiment of the invention, as defined in the broadest claim, must be capable of being realised on the basis of the disclosure. This implied in particular that an objection of insufficiency could be raised against the subject-matter of any claim, independent or dependent (R. 29(3) EPC 1973, now R. 43(3) EPC). From a legal point of view it was therefore irrelevant whether or not the feature objected to was essential or to what degree the scope of protection conferred by the patent depended on the claim in question (T 226/85 (OJ 1988, 336), cited in many decisions, for example, T 1011/01 and T 1129/09). The board in ex parte case T 206/13 could not accept the appellant's submissions to the effect that preferred or optional features defined in a claim should be disregarded in the assessment under Art. 83 EPC. According to the established case law the requirement of sufficiency of disclosure defined in Art. 83 EPC was only complied with if the disclosure of the invention allowed the skilled person to perform, without undue burden, essentially all the embodiments covered by the claimed invention. This applied in particular to the specific particular embodiments of an invention defined in dependent claims pursuant to R. 43(3) EPC (T 1011/01) and, by the same token, to any optional feature defined in a claim, since such a feature also constituted, by its very nature, a particular embodiment of the claimed invention, irrespective of whether the optional feature was qualified as being "preferred" or not.
In T 797/14 the board came to the conclusion that the essential element of the claimed invention, namely the coating composition Flurotec (TM), was not of public knowledge and that there was also not enough information available to the skilled person for him to reliably determine the composition or structure of the product. The counterpart of a monopoly by a patent is however the disclosure of the invention, in particular of its essential elements, and not the provision or use of a commercial product whose structure and composition are not public.
Disclosure is insufficient if the skilled person, taking into account the entire teaching of the patent, cannot rework an invention which is defined in the claims in a completely clear and comprehensible manner, unless he disregards a meaningful feature (T 432/10).