A decision by the Court of Milan (R.G. 54450/2012) in January 2015 held that an Italian part of a European patent was invalid for, inter alia, having a lack of essential features in the independent claims.

This article first appeared in World Intellectual Property Review, published by Newton Media Ltd.

The patent concerns a method for cleaning heaters through localised explosions generated through a balloon containing an explosive mixture. According to the reasons for the decision, the independent claims at issue lacked essential features insofar as they failed to specify the type of material that the balloon should be made of to avoid a premature detonation, while the scope of the invention is to ensure that the balloon can withstand high temperature.

This reason for invalidating a patent is noteworthy because it shows that a clarity-related issue may harm an Italian patent, even though clarity is not included in the grounds for patent invalidity set out under article 76 of the Italian Patent Law. Rather, clarity requirements are set out in article 21(4) of the Implementing Regulation of the law.

In this respect, one may wonder whether outside Italy patent clarity qualifies as a means for challenging a granted patent. In Europe, article 138 of the European Patent Convention (EPC) excludes clarity from the grounds for national revocation. Accordingly, under article 100 of the EPC clarity is not a ground of opposition although, under European Patent Office case law (G3/14), clarity can (and should) be checked if amendments carried out during the opposition introduce non-compliance with article 84 of the EPC.

However, elsewhere in the world, clarity-related requirements do constitute a ground for invalidating a patent, before either a court or a patent office. For example, patent definiteness in the US is a ground for challenging a patent before the courts and for patent revocation through post-grant review under 35 USC §112. As another example, in Japan, clarity is a ground for patent revocation before the courts and through the recently re-introduced opposition proceeding.

So, clarity is made available to different extents, depending on the jurisdiction, to those who need to challenge the validity of a patent. However, unlike other important requirements for the grant of a patent, such as novelty, obviousness, sufficiency of disclosure and addition of new subject matter, clarity cannot be easily identifiable in a single requirement. Rather, it includes a number of “clarity-related requirements” that may be grouped into categories of deficiencies to be avoided in the patent

Important requirements
A first category of such requirements includes deficiencies that inhibit a precise identification of the boundaries of the scope of protection, such as vague terms or the use of functional features. This aspect is of particular relevance in the interpretation of the claim during an infringement discussion, but normally does not affect the claim of a granted patent.

Second, there can be inconsistencies between the description and the claims, where the specific examples provided in the description do not justify the extent of generalisation defined by the claims. This situation, where the claims lack support, partially overlaps with the provision of sufficiency of disclosure, which is always a ground for invalidating a patent.

A third category includes situations where the wording of an independent claim fails to reflect the technical achievement attributed to the claim, that is, where the claim lacks essential features. This problem typically arises when a link is established between the independent claim and a specific result, where the claim covers at least one “non-working” embodiment which is unable to achieve such a result, and is particularly tricky, especially in Europe.

Fourth, there might be minor deficiencies, such as lack of antecedent basis and inconsistent use of terms or numbers to indicate features. These deficiencies rarely harm a granted patent.

In light of the above, practitioners may sometimes overlook the relevance that clarity-related issues could have for a patent. Instead, particular care should be taken in checking clarity of the claims, especially at the time of drafting, since clarity problems are usually “built into” the patent text and can be hard to fix at later stages.