3.1.4 Reference to common general knowledge

The priority of a previous application in respect of a claim in a European patent application in accordance with Art. 88 EPC is to be acknowledged only if the skilled person can derive the subject-matter of the claim directly and unambiguously, using common general knowledge, from the previous application as a whole (G 2/98, OJ 2001, 413).

According to earlier decision T 136/95 (OJ 1998, 198), a patent application is a technical document, addressed to the skilled person, not a work intended for the general reader. However, the skilled person is not familiar, unlike in the assessment of inventive step, with all the prior art, but only with those elements of it which form part of his general knowledge, and it is on the basis of this knowledge, or by carrying out simple operations derived from it, that he may infer whether or not there is identity of invention. In the case in question a structural feature claimed in the European application was supported by a general functional feature described in the prior application.

Applying G 2/98 (OJ 2001, 413), the board in T 744/99 held that the application of common general knowledge could only serve to interpret the meaning of a technical disclosure and place it in context; it could not be used to complete an otherwise incomplete technical disclosure. In the case in hand, since the priority document only disclosed a new signal protocol without any disclosure of a suitable receiver, claim 8 of the subsequent application, which was directed to such a receiver, was not entitled to the claimed priority date.

In T 1312/08 the patent proprietor had submitted that the definition of "PU" was correct in the patent in suit but erroneous in the priority document. The board, referring to the established jurisprudence, stated that the reworking of an example and especially of a method which was not a standardised one and was not reported in encyclopaedias, textbooks, dictionaries and handbooks could not be considered to be the application of common general knowledge. The mere fact that it was necessary to carry out a test, which was not part of common general knowledge, in order to find out whether the definition of PU in the priority document was erroneous made it clear that the different definition of PU used in the patent in suit was not derivable directly and unambiguously, using common general knowledge, from the whole content of the priority document. See also T 1579/08.