Guide to construction

2.33 While the description and claims are to be read together, they serve different functions: the description is intended to convey to the public what the patentee considers is the invention, and the claims set out the monopoly the patentee has chosen to obtain. These are not necessarily the same (First Currency v Mainline [2008] 1 SLR 335, citing Laddie J in Merck & Co. Inc. v Generics (UK) Ltd [2004] RPC 31). To this end, the claims may be narrower than what is disclosed in the specification, but the claim must never be broader than what is supported by the specification.

2.34 Each claim should be read giving the words the meaning and scope which they normally have. However, the everyday meaning of words used in a claim may not be their true meaning when read in the light either of a definition found elsewhere in the specification or of technical knowledge possessed by persons skilled in the art (Fabio Perini SPA v LPC Group plc and others [2010] EWCA Civ 525 and Occlutech GMBH and anr v AGA Medical Corp. and anr [2010] EWCA Civ 702). Therefore, the claim should also be read with an attempt to make technical sense of it; such a reading may involve a departure from the strict, literal meaning of the wording of a claim (see subsection of this Section on “Special meanings”).

2.35 Prior art references may be useful when construing terms used in a specification. For example if the specification identifies a particular feature of the prior art as having a problem that the inventor has overcome, then the terms used in relation to that particular solution may be construed as excluding the prior art feature. However, even where a purposive approach is taken to construing specifications, if a term in a claim is used in a manner that is inconsistent with the meaning given to it when the specification is considered as a whole, then the claim will lack clarity (IGT/Acres Gaming Inc.’s Application [2008] EWHC 568). In such cases the scope of the claim would be rendered unclear to the person skilled in the art. As noted in Glaverbel S A v British Coal Corporation [1995] RPC 255, the claims should be read together with the body of the specification; but if a claim is expressed in clear language, the monopoly sought cannot be extended or cut down by reference to the rest of the specification.

2.36 During examination, Examiners should avoid making the claim say something that it does not say at all, or create ambiguities which do not reasonably exist. Where there is a choice between two meanings of a claim, one should, if possible, reject that meaning which leads to an absurd result in favour of one that works.