As a general rule, an applicant is free to draft a patent claim
in any desired claim language; the same is true for the
accompanying description. However, when an invention manifests in
particular parameters and the invention shall be protected by a
European patent granted under the European Patent Convention, some
particular issues may arise. Five of these issues are discussed in
this paper. Contrary to Hamlet, we must ask not only one question
in this context, but several.
Clarity
Is it usual, or is it not usual: that is the
question.
Although a product may be defined in a claim in various ways,
the Guidelines for Examination in the European Patent Office
(hereinafter: "the Guidelines") state that a product
should only be exceptionally defined by its parameters. In this
context, parameters are considered to be characteristic values,
which may be values of directly measurable properties or may be
defined as more or less complicated mathematical combinations
