The term ‘features’ means the parts of the invention and their relationship to one another. A 'feature' can be a physical component, a chemical substance/composition, or a process step.

Identifying essential features

Consistory clauses

The essential features are often stated in ‘consistory clauses’ following statements such as ‘according to the present invention’, ‘the invention resides in’, ‘the present invention provides’, or similar. The description normally contains a consistory clause, unless it states what the invention is without ambiguity.

Often the main (independent) claims will contain text identical to the consistory clauses. Australian case law indicates that this drafting practice does not automatically mean the claims are supported by the description.

A consistory clause may be a strong indication of the broadest form of the invention, but it is not definitive. The examiner also needs to consider the specification as a whole.

Essential

A statement that a feature is ‘essential’ usually indicates that the feature is part of the invention. However, consideration must be given to other parts of the specification which may indicate that the feature is not actually essential.

Examiners need to determine whether the feature is a core element of the invention, or merely essential for the working of a preferred embodiment.

Preferred

A statement that a feature is ‘preferred’ usually indicates that the feature is not part of the broadest form of the invention. However, after considering the specification as a whole, the examiner may determine that a ‘preferred’ feature is in fact an essential part of the invention.

Relevant case law

What is the Invention?

In Kimberly-Clark Australian Pty Ltd v Arico Trading International Pty Ltd (2001) 207 CLR 1, the High Court (at paragraph 21) discussed the various ways the term “invention” is used in patent law. The High Court noted that there were four possible meanings of the word “invention”:

"They are: 1. The embodiment which is described, and around which the claims are drawn. This is the sense used in the Act: cf. the phrase of s 32, 'the invention so far as claimed in any claim. 2. The subject-matter of a claim - especially that of the broadest claim. 3. The inventive step taken by the inventor. 4. The advance in the art made by the inventor; as (to take Lord Justice Moulton's example) 'he applied electricity for the first time to such-and-such a purpose.' This is likely to be broader and more fundamental than would correspond with any claim."

The High Court indicated it was the first meaning that is used for the purposes of sec 40(2) (full description). This meaning also flows through to fair basis (sec 40(3)), which requires consistency between the described and claimed invention.

"Essential Features" of the Invention

Lockwood v Doric [2004] HCA 58 at paragraph 68 states:

“The comparison which s 40(3) calls for is not analogous to that between a claim and an alleged anticipation or infringement. It is wrong to employ "an over meticulous verbal analysis". It is wrong to seek to isolate in the body of the specification "essential integers" or "essential features" of an alleged invention and to ask whether they correspond with the essential integers of the claim in question”.

As noted in Rehm Pty Ltd v Websters Security Systems (International) Pty Ltd 11 IPR 289:

"The circumstance that something is a requirement for the best method of performing an invention does not make it necessarily a requirement for all claims; likewise, the circumstance that material is part of the description of the invention does not mean that it must be included as an integer of each claim. Rather, the question is whether there is a real and reasonably clear disclosure in the body of the specification of what is then claimed, so that the alleged invention as claimed is broadly, that is to say in a general sense, described in the body of the specification."

5.5.2.4 The invention described

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