The principles set out there will also apply mutatis mutandis to the opposition procedure. The overriding consideration in this context is the disclosed content of the European patent specification, that is to say what a person skilled in the art is able to infer from the patent claims, description and drawings, if any, without reflection as to inventiveness. Pursuant to Art. 100(b), the patent has to disclose the invention in a manner sufficiently clear and complete for it to be carried out by persons skilled in the art. If the patent specification does not disclose the invention sufficiently clearly to enable it to be carried out in accordance with Art. 100(b), this may be remedied, provided the original documents contained a sufficient disclosure, but subject to the condition that, as required under Art. 123(2), the subject-matter of the European patent does not extend beyond the content of the application as filed and, as required under Art. 123(3), the protection conferred is not extended.
There is normally no deficiency under Art. 100(b) EPC if a feature which is essential for performance of the invention is missing from the claim but is disclosed in the description and/or drawings. However, unduly broad claims may be objected to under Art. 56 (see T 939/92).