When drafting patent applications, the choice of wording, particularly that of the claims, is always highly important. With the correct wording, you can avoid trouble relating to the relevant patent law.
Clear and concise claims
The European Patent Convention, among others, indicates that a patent application should disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art, while another section of the Convention states that the claims should be clear and concise and be supported by the description.
Thus, clarity and a complete description or a description providing support for the claims is mentioned in both sections. The main difference between the sections is that one focuses on the claims, and their clarity and support, while the other focuses on the description, and the support it provides to the claims.
An invention vs. the invention
There exists also another interesting issue, where the above mentioned section mentioning the disclosure of the invention in the description is compared to a further section focusing on the inventive step, or non-obviousness, of the invention.
The former section states that the application shall disclose “the” invention, whereas the latter section mentions “an” invention, and continues by comparing this invention to the state of the art.
Disclosure at the point of drafting
The sufficient disclosure must be included in the description of the application at the point of drafting, after which no new matter or support can be introduced into the application.
However, the inventive step is determined based on the wording of the claims, which can be amended long after the point of drafting the application. For example, an amendment of the claims could have been made in view of a prior art document that became known to the applicant long after the application was filed at the Patent Office. Such an amendment could even be based on a feature that was mentioned in the original application as a type of by-plot.
However, the description in its original form should still provide sufficient support for the invention, as described in the amended claims.