Through over a decade of translating written opinions of the Searching Authority on patent applications, one of the common objections we see raised by examiners is that of a patent application lacking clarity.

A patent application must satisfy Patent Cooperation Treaty (PCT) Article 6, which specifies that:

“The claim or claims shall define the matter for which protection is sought. Claims shall be clear and concise. They shall be fully supported by the description.”

Although this rule seems simple enough, it is actually surprising just how many ways in which a set of claims can be made unclear.

Often the applicant will unwittingly assume that broadening the scope of their claims will increase their acceptance and success — ‘casting their net as wide as possible to ensure the best catch’. The applicant will attempt this by including lots of combinations and permutations of the subject matter.

This is often done by using expressions like “in particular”, “preferably” and “and/or”, which actually have no limiting effect on the invention and only reflect optionality (optional features).

When multiple dependent claims are presented, the “and/or” combinations can lead to many permutations of the invention that can even make a prior art search impossible for the examiner or simply “make the claim obscure or difficult to construe” (PCT Guidelines 5.18).

Too many possibilities and alternatives simply lead to a lack of clarity with respect to the claims in their entirety because it is too difficult or impossible to determine the scope of protection. This is one good reason why claims should be drafted “concisely”.

Particular care should be taken to ensure that all the implied combinations are also actually feasible and consistent, i.e. “can fairly be substituted one for another” (PCT Guidelines 5:18). It is common for dependent claims to be invalid for some combinations of “and” and “or” (when “and/or” is used). The applicant should therefore ask themselves whether a claim actually works for just an “and” combination and just an “or” combination of a claim to which it refers back and is dependent on.

In summary, when drafting claims, always ensure that the subject matter is limited and that any alternatives are supported across all the claims. Cares should be taken with words such as “in particular”, “and/or”, “preferably”, “for example” and “such as”. Be wary of the fact that such words or phrases will likely render features that follow them optional and therefore not provide any protection for them (PCT Guidelines 5:40).