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How Could My Patent Claim Possibly Be Any Clearer For The European Patent Office?


As a European patent attorney, I sometimes wonder whether European Patent Office (EPO) practice on patent claim clarity is influenced by a quote attributed to the Greek physician, Hippocrates:

“The chief virtue that language can have is clarity”.

Whilst ensuring that a patent claim is ‘clear’ may indeed be virtuous, it seems unlikely that patent claim clarity is intended to be the chief virtue of a patent when the European Patent Convention (EPC) specifies the main criteria for judging whether a patent shall be granted as follows:

“European patents shall be granted for any inventions, in all fields of technology, provided that they are new, involve an inventive step and are susceptible of industrial application”.

Of course, the EPC includes other requirements that must be met before a patent can be granted. For example, on clarity, the EPC specifies that:

“[t]he claims shall define the matter for which protection is sought. They shall be clear and concise and be supported by the description”.

It is not the intention of the EPC that clarity should represent a significant bar to obtaining a European patent when clarity is not even a legitimate ground for opposing a granted European patent.

However, patent law practitioners will be aware that the EPO can sometimes raise clarity objections that can be difficult to overcome, which is frustrating, particularly when the invention makes a genuine contribution over the art.

It is helpful to gain an understanding of the EPO’s philosophy on clarity, particularly as the EPO’s approach is seen as being stricter than in other jurisdictions. This article explores some of the basic principles of clarity at the EPO.

We must first ask what does it mean for a claim to be ‘clear’?

There is no specific guidance in the EPC. Instead, case law has established the EPO’s present approach towards clarity with which many practitioners in patent law will be familiar. In particular, the claims:

“must be clear in themselves when read by the person skilled in the art, without any reference to the content of the description”.

This means that features and functionality defined by a claim must be fully understandable to the person skilled in the art without referring to the description. Of course, the description shall still provide useful context for the invention.

In some cases, it is possible to address a clarity objection by argumentation alone. As indicated by the case law, such argumentation generally needs to refer to the claims themselves rather than the description.

It can be highly tempting to argue that the person skilled in the art would readily understand an allegedly unclear feature with reference to the description. Unfortunately, such arguments are unlikely to succeed in view of the case law.

In other cases, an amendment is needed to overcome the clarity objection.

For example, a claim may specify functionality such as ‘determining a value based on received data’. Depending on the context of the claim, such functionality is potentially unclear because the claim does not specify how exactly the value is determined based on the data.

One possible solution is to amend the claim to define ‘determining a value by implementing a specified procedure (where the details of the ‘specified procedure’ are explicitly recited in the claim). If the specified procedure covers all the necessary embodiments, the amendment may be acceptable. However, if the specified procedure is specific to a single embodiment to the exclusion of other embodiments, the amendment may be unacceptable to the applicant.

There are some scenarios where added matter concerns makes it very difficult or even impossible to amend a claim in such a way that would overcome a clarity objection.

Compared to many other jurisdictions, the EPO has an incredibly strict approach when reviewing amendments for added matter. This means that whilst there may well be a suitable amendment to resolve a clarity issue, unless there is EPO-level support for the amendment, the EPO’s approach to added matter may prevent such an amendment being made. In some cases, this interplay between clarity and added matter may represent an inescapable trap.

In view of the EPO’s approach to added matter making it potentially difficult to amend a patent application after it has been filed, the best time to think about clarity is during the drafting of a patent application. Some (non-exhaustive) tips to consider when drafting a patent application that will potentially be prosecuted in Europe include:

  1. Taking the time to review and revise the claims in collaboration with the inventors when drafting a patent application, though this may not always be possible due to time constraints.
  2. Seeking constructive feedback from another patent attorney, particularly a European patent attorney if the patent application is being drafted by a non-European patent attorney.
  3. Ensuring that all features defined in the claims are adequately defined in the description to provide support for future amendments, if needed.
  4. Ensuring that the application includes as many broad statements as possible to cover intermediate positions between the broadest claims and the particular embodiments, and these statements should be drafted in such a way to allow individual statements to be extracted in isolation from the description.

Clarity objections are common at the EPO and force patent attorneys to think very carefully and creatively about how to address such objections. Whilst clarity is not intended to be a significant bar to patentability in Europe, applicants may improve the chances of obtaining a European patent with a commercially useful scope of protection if awareness of the problems posed by EPO-style clarity and added matter objections can be taken into consideration during the drafting phase.

This is for general information only and does not constitute legal advice. Should you require advice on this or any other topic then please contact or your usual HLK advisor.

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