Refresher: Disclaimers
A disclaimer is a negative feature that is excluding a certain element.
There are two basic types of disclaimer: “undisclosed” and “disclosed”.
Undisclosed: the subject-matter to be disclaimed cannot be found in the European patent application as originally filed.
Disclosed: it is present in the application as filed, generally as one of the embodiments of the invention.
Undisclosed disclaimers - G 1/03 and G 2/03
Adding a disclaimer without a basis in the application as filed may be allowable under Art. 123(2) EPC only in the following cases:
1) restoring novelty over a disclosure under Art. 54(3);
2) restoring novelty over an accidental anticipation under Art. 54(2);
("An anticipation is accidental if it is so unrelated to and remote from the claimed invention that the person skilled in the art would never have taken it into consideration when making the invention.")
3) removing subject-matter which, under Art. 52 to Art. 57, is excluded from patentability for non-technical reasons. For example, the insertion of "non-human" in order to satisfy the requirements of Art. 53(a) is allowable.
In cases 1) and 2), the disclaimer may not remove more than necessary to restore novelty! (Disclaimers are not allowed if they make a technical contribution or if the limitation is relevant for assessing inventive step.)
A claim containing a disclaimer must meet the clarity and conciseness requirements of Art. 84 EPC.
See more in Guidelines H-V, 4.2.
Another related G decision is G 1/16 which confirms that an undisclosed disclaimer is allowable under Art. 123(2) EPC if the disclaimer fulfils one of the criteria set out in G 1/03.
Disclosed disclaimers - G 2/10
Adding a disclosed disclaimer must also satisfy the requirements of Art. 123(2) EPC.
The question is whether it is permissible to disclaim (negatively) subject-matter disclosed (positively) as an embodiment of the invention in the application as filed.
The test to be applied is whether the subject-matter remaining in the claim after the introduction of the disclaimer is, be it explicitly or implicitly, directly and unambiguously disclosed in the application as filed to the skilled person using its common general knowledge at the date of filing (or the date of priority according to Art. 89), see G 2/10.
For example, when an application as filed discloses an invention in general terms together with a number of specific embodiments, the general teaching of the application will not normally be modified by a disclaimer which excludes one of the disclosed embodiments from the claimed subject-matter. Therefore, a positively disclosed feature can typically be turned around and formulated as a negative disclaimer. (This example was copied from the EPO pre-exam course.)