Patent claims are usually in the form of a series of numbered expressions following the description of the invention in a patent or patent application, and define, in technical terms, the extent of the protection conferred by a patent or by a patent application, when applicable. They are of the utmost importance both in examination proceedings and in litigation, for instance during infringement actions.
There are two basic types of claims:
- the independent claims , which stand on their own, and
- the dependent claims , which depend on a single claim or on several claims and generally express particular embodiments as fall-back positions. When a claim in one particular category (see below), e.g. a process claim, depends on a claim from a different category, e.g. a product claim, it is not considered to be a dependent claim but an independent claim (at least under the European Patent Convention).
Claims can also be classified in categories, i.e. in terms of what they claim. A claim can refer to
- a physical entity, i.e. a product (or material) or an apparatus (or device, system, article, ...). The claim is then called respectively "product claim" or "apparatus claim"; or
- an activity, i.e. a process (or method) or a use. The claim is then called respectively "process claim" (or method claim) or "use claim".
Patent have not always contained claims. In many European countries, patents did not contain claims before the 1970s. It was then often difficult (and subjective) to decide whether or not a product infringed a patent, since the sole basis to know the extent of protection was the description, in view of the prior art.
Under the European Patent Convention (EPC), a claim must define the matter for which the protection is sought in terms of technical features. These technical features can be either structural (e.g. a nail, a rivet) or functional (e.g. fastening means).
Special types of claims
A so-called omnibus claim is a claim including a reference to the description or the drawings without stating explictly any technical features of the product or process claimed. For instance, they may read for instance " Apparatus as described in the description ".
Omnibus claims are not allowed under the EPC "except when they are absolutely necessary."
A product-by-process claim is a product claim where the product is defined by its process of manufacture, especially in the chemical and pharmaceutical industries. They may read for instance " Product obtained by the process of claim ... ".
According to the European practice, they should be interpreted as meaning " Product obtain able by the process of claim... ". They are only allowable if the product is patentable as such, and if the product cannot be defined in a sufficient manner on its own, i.e. with reference to its composition, structure or other testable parameters, and thus without any reference to the process.
The protection conferred by product-by-process claims should not be confused with the protection conferred to products by pure process claims, when the products are directly obtained by the claimed process of manufacture.
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