European Patent Office (EPO) examiners have an approach to assessing device (or apparatus) claims that can seem somewhat alien to those more familiar with practice before other patent offices. We focus here on two issues that can trip up the unwary.

Claim interpretation issues dressed up as prior art issues

Arguably the most common issue that crops up during prosecution of device claims at the EPO is that of examiners presenting what are in practice claim interpretation issues as prior art issues.

At the EPO, many novelty and inventive step objections to device claims are not really prior art issues at all; instead, they are ‘I am interpreting this claim term to cover something that you did not intend it to cover’ issues. The examiner doesn’t make a clarity objection (under Article 84 EPC), because the claim term is ‘clear’ in the strict sense; it’s just that the drafting attorney and the examiner each think it has different boundaries, and the examiner’s broader boundary encompasses the prior art.

Such issues are only rarely spelled out explicitly by the examiner; instead, some reading-between-the-lines of the objection is required.

The issue often arises because the EPO is unusual in (generally) requiring the meaning of claim terms to be clear from the claim itself, without reference to the description. This can result in a rather broad interpretation of claim terms by EPO examiners.

In practice, where there is a claim term that the EPO examiner thinks can be interpreted more broadly than intended, a clarifying amendment is usually the answer. In many cases it is possible to find an amendment that doesn’t make the term narrower than the drafting attorney originally intended it to be. Functional claim limitations can be particularly helpful in such situations.

To avoid claim amendment it will generally be necessary to provide a strong argument explaining why the examiner’s interpretation is wrong, and why the claim term can only be interpreted in the intended way. An argument simply referring to a definition in the description will rarely be successful, because of the EPO’s approach to claim interpretation described above.

Of course, sometimes no amount of reading-between-the-lines can help you understand the examiner’s point of view. In such cases there is really no substitute for picking up the phone and discussing the objection with the examiner.

Added matter and the ‘intermediate generalisation’

Possibly the biggest potential stumbling block that patent applications originating outside of Europe face when being prosecuted in Europe is the issue of added subject matter (Article 123 EPC). This issue has many different guises, but at its core is the maxim that the EPO does not allow the applicant to claim subject matter that was not ‘clearly and unambiguously disclosed’ in the application when it was first filed.

When it comes to device claims, the most common (and most misunderstood) trap for the unwary is the ‘intermediate generalisation’. It is perhaps best explained by considering an example. Your application includes a description of an embodiment which includes Feature A. You want to add Feature A into claim 1, but the examiner says that the embodiment discloses Feature A in combination with Features B, C, D and E, and only features B and C are in claim 1 already. The argument is that your application discloses a combination of Features A-E, and your claim to Features A, B and C is an ‘intermediate generalisation’ since it presents a new combination not disclosed in the application as filed.

Such objections can be overturned if the examiner can be persuaded that Feature A is not “related or inextricably linked” to Features D and E, and the overall disclosure “justifies the generalising isolation” of the feature and its introduction into the claim.

However, it is of course preferable to avoid such objections in the first place. This is most effectively done by including in the application as filed dependent claims or subsidiary statements of invention directed to any features that the applicant might want to ultimately include in an independent claim. A reasonable alternative is to ensure that the embodiments clearly identify those features which can be isolated from others, and/or identify non-essential features of the embodiments. It is often not enough simply to list all the features of the embodiments as ‘optional’; EPO examiners can argue that this type of approach does not satisfy the criteria set out above.


The above outlines just a few ways in which the EPO operates differently to some other patent offices when it comes to the examination of device claims, but of course there are plenty of others! Ultimately, the most important role that your European patent attorney colleague has is to guide you through the EPO process and help you avoid the traps.