The subject matter encompassed by a patent claim is usually defined in terms of positive features. Occasionally, however, it may be desirable to define the scope of protection in terms of a negative feature. This is referred to as a ‘disclaimer’.
Disclaimers and their interaction with the European Patent Office’s (EPO) strict approach to added subject matter under Article 123(2) EPC was considered by the EPO Enlarged Board of Appeal in the combined decisions G1/03 and G2/03. These looked at the situation where neither the subject matter to be disclaimed nor a disclaimer as such was disclosed in the application as originally filed. It was determined that these ‘undisclosed disclaimers’ could be allowed in certain circumstances (for example when excluding prior art citable for the purposes of novelty-only under Article 54(3) EPC). G1/03 provided guidance on the form that a disclaimer should take (see the Guidelines for Examination in the EPO, C-VI, 5.3.11).
The law set out in G1/03 and G2/03 for introducing undisclosed disclaimers has been followed in subsequent decisions of the Technical Boards of Appeal. In addition, the Guidelines for Examination in the EPO were amended to state that “disclaimers excluding embodiments that were disclosed in the original application as being part of the invention are considered as undisclosed disclaimers” (see C-III, 4.20).
In view of the above case-law and practice, it seemed clear that the introduction of a disclosed disclaimer – a disclaimer where the subject matter to be disclaimed was explicitly disclosed – would only be allowed in the same limited circumstances in which an undisclosed disclaimer might be permitted.
This practice could lead to a situation where an Applicant would have to narrow the scope of protection by introducing positive features in order to overcome a piece of prior art that disclosed a single embodiment of the invention. The ability to cut out a discreet disclosed embodiment was, it seemed, limited to only certain circumstances.
More recently, a divergence in the approach taken to disclaimers has developed between different Boards of Appeal such that further clarification became necessary (as noted in the Enlarged Board’s decision G1/07).
In decision T1068/07 the Technical Board of Appeal referred the following question to the Enlarged Board of Appeal:
“Does a disclaimer infringe Article 123(2) EPC if its subject-matter was disclosed as an embodiment of the invention in the application as filed?”
On 30 August 2011 the Enlarged Board of Appeal answered this question in decision G2/10. After discussing the different scenarios in which the introduction of a disclaimer might be attempted and considering the amicus curiae briefs, the Enlarged Board answered the referred question as follows:
“1a. An amendment to a claim by the introduction of a disclaimer disclaiming from it subject-matter disclosed in the application as filed infringes A 123(2) if the subject-matter remaining in the claim after the introduction of the disclaimer is not, be it explicitly or implicitly, directly and unambiguously disclosed to the skilled person using common general knowledge, in the application as filed.”
Thus, a positively disclosed feature may be used as the basis for a disclaimer, provided that the remaining subject matter, i.e. the original claim scope minus the disclaimed scope, was itself directly and unambiguously disclosed in the application as filed.
Determining if the remaining subject matter was directly and unambiguously disclosed in the application as filed may prove to be a difficult task in some cases. The Enlarged Board acknowledged this and provided some guidance in a second part to their answer; pointing out that the determination of disclosed subject matter must be determined on a case-by-case basis:
“1b. Determining whether or not that is the case requires a technical assessment of the overall technical circumstances of the individual case under consideration, taking into account the nature and extent of the disclosure in the application as filed, the nature and extent of the disclaimed subject-matter and its relationship with the subject-matter remaining in the claim after the amendment.”
Although the Enlarged Board indicated that existing practices on the introduction of amendments should be applied, there may still be some uncertainty as new procedures are adopted with the intention of ensuring amendments comply with this new case law.
There will be some disappointment that the Enlarged Board did not take this opportunity to provide a ‘one-size-fits-all’ rule that could be applied with more certainty. However, this decision does at least confirm that the possibility remains of using a positively disclosed embodiment as the basis for a disclaimer. G2/10 therefore means that this invaluable tool for establishing the novelty of claims when amending European patent specifications is now at the disposal of all Applicants, providing of course that certain conditions are met.