Article 83 of the European Patent Convention (EPC) relates to the disclosure of the invention under the European Patent Convention. This legal provision prescribes that a European patent application must disclose the invention (which is the subject of the European patent application) in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.
Basic principles To comply with Article 83 EPC, a European patent application must contain sufficient information to allow a person skilled in the art, using his common general knowledge and the information provided in the application, to perceive the technical teaching inherent in the claimed invention and to put it into effect accordingly.Decision G 2/93 of the Boards of Appeal of the European Patent Office dated December 21, 1994, Reasons 4. In other words, the disclosure of the invention must be reproducible without undue burden,Decision T 63/06 of 24 June 2008, reasons 2.2, ".. according to the well established case law of the Boards of Appeal .. the disclosure must be reproducible without undue burden." See also "Reproducibility without undue burden". and this must be true over the whole scope of the claim. "Invention to be performed over whole range claimed"; T 792/00 of 2.7.2002, Reasons 2; T 713/15 of 2.10.2019, reasons 4.4, fourth paragraph: "As a consequence of these findings, the subject-matter of claim 1 of the main request is not sufficiently disclosed over the whole scope of the claim."Decision T 0435/20 of 14.7.2022, reasons 23: "According to the established case law of the Boards of Appeal, a patent complies with the requirement of sufficiency of disclosure if the skilled person, on the basis of the information provided in the patent and taking into account the common general knowledge, is able to perform the invention as claimed in the whole range claimed without undue burden, i.e. with reasonable effort (...)." Further, even if an invention "requires a certain amount of experimentation by the skilled person to carry it out", the invention may still be considered as sufficiently disclosed "as long as this experimentation is not an undue burden on the skilled person".Decision T 0435/20 of 14.7.2022, reasons 60, first sentence.
In the context of assessing sufficiency of disclosure, the EPO considers that, although a claim must be construed with a mind willing to understand, this does not require that a technically broad but clear term be interpreted more narrowly in the light of a limiting feature mentioned only in the description.T 0989/16 (Post translationally modified glycoproteins/LIFE TECHNOLOGIES … of 4.12.2020, reasons 4: "The board follows the established case law that construing a claim with a mind willing to understand does not require that a technically broad term is interpreted more narrowly (see for example decision T 1408/04, reasons 1)."; reasons 4.2, first paragraph: "(...) a limiting feature mentioned in the description only (...) which is missing in the claims cannot be read into them and so inserted merely through interpretation. The only way is to amend the claims to incorporate it."; and reasons 4.2, second paragraph: "Since the method of claim 1 (...) does not comprise any unclear term requiring a further interpretation, there is no reason and no leeway to limit the clear wording of claim 1 to (...)"
The requirement of sufficiency of disclosure must be complied with as from the date of filing because a deficiency in a European patent application as filed, consisting in an insufficient identification of the subject-matter claimed, cannot subsequently be cured without offending against Article 123(2) EPC, which provides that the subject-matter content of a European patent application as filed may not be extended.Decision G 2/93 (cited above), Reasons 10.
An insufficiently clear and complete disclosure of the invention is a ground of opposition, and revocation.
Violation of the generally accepted laws of physics Although the European Patent Convention does not exclude the patenting of "revolutionary" inventions, Decision T 1329/07 of the Technical Board of Appeal 3.4.02 of 11 November 2010, point 2.2.3
Burden of proof in opposition The burden of proof generally lies upon an opponent to establish insufficiency of disclosure.: "The burden of proof generally lies with the opponent to establish that an invention is insufficiently disclosed (...)"; and : "In order to establish insufficiency of disclosure in inter partes proceedings, the burden of proof is upon an opponent to establish, on the balance of probabilities, that a skilled person reading the patent, using his common general knowledge, would be unable to carry out the invention (see decision T 182/89, OJ 1991, 391)" (emphasis in the original).Decision T 63/06 of 24 June 2008, headnote: "The burden of proof generally lies upon an opponent to establish insufficiency of disclosure. (...)".Decision T 1727/12 of 1 February 2016, point 1.1: "A principle intrinsic to EPO proceedings is that the party who raises an objection bears the burden of proving it (see "Case Law of the Boards of Appeal of the EPO", 7th edition, 2013, III.G.5.1.1). The application of this principle to opposition proceedings leads to the conclusion that the burden of proof in respect of the grounds for opposition raised by an opponent lies on the opponent. (...)" However, "when the patent does not give any information of how a feature of the invention can be put into practice" and if the opponent plausibly argues that "common general knowledge would not enable the skilled person to put this feature into practice", the burden of proof can be shifted to the patentee to show that "common general knowledge would indeed enable the skilled person to carry out the invention."Decision T 63/06 of 24 June 2008, headnote: "(...) When the patent does not give any information of how a feature of the invention can be put into practice, only a weak presumption exists that the invention is sufficiently disclosed (...). In such case, the opponent can discharge his burden by plausibly arguing that common general knowledge would not enable the skilled person to put this feature into practice."
Relationship between Articles 83 and 84 EPC Depending upon the circumstances, an ambiguity in the claims (i.e. a lack of clarity under ) may very well lead to an insufficiency objection.Decision T 608/07 of 27 April 2009 of EPO Board of Appeal 3.3.03, Reasons 2.5.2. As held in decision T 608/07 of 27 April 2009 (in opposition appeal proceedings), "[it] should be born in mind that [such an] ambiguity also relates to the scope of the claims, ie Article 84 EPC. Since, however, Article 84 EPC is in itself not a ground of opposition, care has to be taken that an insufficiency objection arising out of an ambiguity is not merely a hidden objection under Article 84 EPC. (...) [For] an insufficiency arising out of ambiguity it is not enough to show that an ambiguity exists, eg at the edges of the claims. It will normally be necessary to show that the ambiguity deprives the person skilled in the art of the promise of the invention. It goes without saying that this delicate balance between Article 83 and 84 EPC has to be assessed on the merits of each individual case."
That a lack of clarity in the claims may, in some cases, result in an insufficient disclosure of the invention has been also pointed out by Board 3.2.05 in decision T 1811/13 of 8 November 2016. The Board explained however that: "(...) in such a case it is not sufficient to establish that a claim lacks clarity, but it is necessary to establish that the application or patent, as the case may be, does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. In other words, it is not sufficient to establish a lack of clarity of the claims for establishing lack of compliance with Article 83 EPC (...); it is necessary to show that the lack of clarity affects the patent as a whole (i.e. not only the claims) and that it is such that the skilled person - who can avail himself of the description and his common general knowledge - is hindered from carrying out the invention (...)."Decision T 1811/13 of 8 November 2016, Reasons 5.1, ninth paragraph.
Implementing regulations, especially Rule 42 EPC specifies the content of the description of a European patent application and constitutes an implementing rule of Article 83 EPC. Rule 42(1)(e) EPC (previously ) notably specifies that "[the] description shall ... describe in detail at least one way of carrying out the invention claimed, using examples where appropriate and referring to the drawings, if any." In that respect, "[the] jurisprudence of the boards of appeal draws a clear distinction between the concepts of "way of carrying out the invention claimed" and "examples" referred to in []. ... the detailed description of one way of carrying out the invention claimed has to be interpreted in the light of Article 83 EPC. It constitutes a condition to be met by the description as a whole and is clearly mandatory. In contrast, the presence of examples would only be indispensable if the description would otherwise not be sufficient to meet this requirement. Hence, the purpose of the "examples" evoked in [Rule 42(1)(e) EPC] appears primarily to be to complete an otherwise incomplete teaching."Decision T 990/07 of 23 February 2010, Reasons 3.2, second paragraph.
References
Further reading
: "Sufficiency of disclosure" : "Lack of support vs. insufficient disclosure" : "Insufficient disclosure of the invention" (in opposition proceedings) : "Sufficiency of disclosure"