5.5.4.1 The claims are construed as a legal document

Also in this Chapter:

• ​​​​​​​5.5.4.2 Presumption against redundancy;
• 5.5.4.3 Omnibus claims;
• 5.5.4.4 Swiss claims;
• 5.5.4.5 Product by process claims;
• 5.5.4.6 Parametric claims;
• 5.5.4.7 ‘For use in’, ‘when used’, and similar wording in claims;
• 5.5.4.8 ‘Comprises‘, ‘includes‘, ‘consists of‘, and ‘contains‘ in claims;
• 5.5.4.9 Reference numerals in claims;
• 5.5.4.10 Relative terms;
• 5.5.4.11 ‘Substantially‘, ‘about‘, and ‘generally’; and
• 5.5.4.12 Appended claims.

Key Legislation:

Patents Act:

• s7 Novelty, inventive step and innovative step  
• s7A Meaning of useful  
• s18 Patentable inventions
• s40 Specifications 
• s41 Specifications: micro-organisms  

Related Chapters: 

• ​​​​​​​5.6.7.1 Claims are Clear and Succinct 
• 5.5.3.6 Description construed as a technical document
• 5.6.4 Citations: Prior art base and construction of prior art
• 5.6.5 Novelty, Whole of Contents, and Secret Use
• 5.6.6 Inventive Step
• 5.6.7 Full Disclosure, Sufficiency, Clarity, Support and Usefulness (s40)
• 5.6.8 Patent Eligible Subject Matter (Manner of Manufacture)

Claims viewed as a legal document

The claims in a patent specification define the legal right to a monopoly. Therefore, they are to be construed as a legal document.​​​​​​​

The claims have a special function in the patent specification as they alone define the monopoly. Consequently, the claims will be scrutinised with as much care as any other document defining a legal right (Decor Corp v Dart Industries 13 IPR 385).

​​​​​​​A standard of clarity which may be adequate for the body of the specification is not necessarily adequate for the claims. General terms of uncertain ambit may be objectionable in the claims, even when they are terms which the addressee might be expected to be able to interpret for purposes of performing the invention (British Celanese Ltd.’s Application [1934] 51 RPC 192 at page 195).

This is because the description has the practical purpose of instructing the person in the art how to perform the invention when able to do so, that is, after the patent has expired, whereas the claims define the monopoly, that is, what must not be infringed during the term of the patent (British United Shoe Machinery Co. Ltd v A. Fussell and Sons Ltd (1908) 25 RPC 631). In the body of the specification, the words used may be adequate to enable the invention to be performed, whereas the same words used in the claims may leave competitors uncertain as to the overall scope of the monopoly (AMP v Utilux (1971) 45 ALJR 123)).

The patentee is expected to understand that their claim defines the monopoly for something new, so the skilled reader can assume the patentee did not intend for old material to be encompassed by the claims. (Virgin Atlantic Airways Ltd v Premium Aircraft Interiors UK Ltd (2010) RPC 8 at page 200).