5.1. General principles

A European patent should provide enough information so that a person skilled in the art can understand and put into practice the claimed technical teaching of the invention on the basis of their common general knowledge. According to established case law of the boards of appeal, the disclosure of a patent or patent application should allow a person skilled in the art to successfully perform the claimed invention on the relevant filing date over the whole claimed scope. The disclosure of one embodiment may be sufficient if it allows the desired effect to be obtained without undue burden and with the desired certainty, over the whole claimed scope. In this regard, it is immaterial if some failures occur or some variants are unworkable. The sufficiency of disclosure is a question of fact that must be decided on case-by-case basis. What matters is that, on the relevant date, the average skilled person familiar with the disclosure should be able to perform the claimed invention in line with the inherent technical teaching and produce the claimed subject-matter (T 1173/00, OJ 2004, 16, point 3.2 of the Reasons, which, among other things, summarises the case law, with reference to key decisions, namely T 409/91, points 2 and 3.5 of the Reasons; T 435/91, point 2.2.1 of the Reasons; T 292/85, points 3.1.2 and 3.1.5 of the Reasons; T 612/92, points 12 and 13 of the Reasons).

The applicable case law is also summarised for example in the more recent decisions T 2046/19, T 867/21, T 1298/21, T 548/22 and T 552/22, and T 1977/22 (review and analysis of all landmark decisions).

The patent monopoly should be justified by the invention's technical contribution to the art (T 409/91, OJ 1994, 653; T 435/91, OJ 1995, 188). The need for a fair protection governs both the considerations of the scope of claims and of the requirements for sufficient disclosure (T 292/85, OJ 1989, 275).

Where an applicant did not furnish details of the production process in the description in order to prevent the invention from being copied easily and the missing information could not be supplied from the general knowledge of a person skilled in the art, the invention was held to be insufficiently disclosed (T 219/85, OJ 1986, 376). In ex parte case T 219/85 the invention related to a method for treating a gemstone to provide it with an inscription on one facet. The alleged difference between the method and the prior art giving rise to the different result was expressed simply by the indication "under conditions such". On the other hand, in T 2253/12 the board explained that there was no need for an exhaustive description of generally known technical details to be implemented according to the invention, if such an implementation did not require any undue burden because it was well within the competence of the skilled person (common general knowledge of the skilled person is to be duly taken into account).

Compare this chapter II.C.5. with chapter II.C.7. in the field of biotechnology.

Note that for the chapters below the more recent case law contains numerous decisions that have had to address the interaction between the requirement to disclose at least one way of performing the invention and whether the invention can be performed over its whole scope (for example T 2046/19, T 867/21, T 1298/21, T 548/22 and T 552/22), particularly in light of the technical fields in some cases. This issue of whether the technical field has a bearing on the findings has also been discussed and addressed in the following decisions: T 2773/18; T 500/20; T 1983/19; T 149/21; T 447/22; T 174/21; T 748/19.