Patent lack of novelty, what it is and when a patent can be revoked

For a standard patent to be valid in Australia, the invention it claims must be new. "New" here has a precise legal meaning: the invention, so far as claimed, must be novel when compared with everything that was already publicly available before the claim's priority date. If a single earlier document, or a single earlier act, disclosed the same invention in clear terms, the patent can be revoked for lack of novelty.

This article explains what the novelty requirement involves, the test Australian courts apply when someone challenges a patent on this ground, the perspective from which the question is judged, how revocation actually happens, and the misconceptions that commonly trip up business owners. If you hold a patent, or if a competitor has put a similar product on the market, the difference between a valid and an invalid claim can be worth a great deal of money.

The statutory test for novelty

Section 18(1)(b)(i) of the Patents Act 1990 (Cth) (the Patents Act) makes novelty one of the core requirements of a patentable invention. An invention is a patentable invention only if, when compared with the prior art base as it existed before the priority date of the claim, it is novel. Novelty is assessed claim by claim, and each claim carries its own priority date: generally the date the specification was filed, which can be earlier where an earlier application is relied on.

Section 7(1) of the Patents Act then sets out when an invention is taken to be novel. The invention is novel unless it is not novel in light of any one of the following kinds of information, each of which must be considered separately:

• Single disclosure: prior art information made publicly available in a single document or through doing a single act.
• Related disclosures: prior art information made publicly available in two or more related documents or acts, but only if a person skilled in the relevant art would treat them as a single source of the information.
• Earlier specifications: prior art information contained in a single specification of the kind referred to in the definition of prior art base in Schedule 1 to the Patents Act, which covers earlier-filed patent applications that were published after the priority date.

The key word is "separately". For novelty, the prior art is not accumulated across the whole field. Each candidate disclosure is tested on its own.

The reverse infringement test

The test Australian courts use to decide whether a prior disclosure destroys novelty is known as the reverse infringement test. In Meyers Taylor Pty Ltd v Vicarr Industries Ltd [1977] HCA 19, Aickin J explained that the basic test for anticipation or want of novelty is the same as that for infringement: you ask whether the alleged anticipation would, if the patent were valid, constitute an infringement.

Put another way, the prior disclosure must contain all the essential integers, or features, of the invention as claimed. The comparison is between the single item of prior art and each claim of the patent in suit. If the earlier document discloses every essential integer of the claim, the claim is anticipated and lacks novelty. If even one essential integer is missing from the earlier disclosure, the claim survives on that ground.

The prior disclosure must be clear and complete

Not every hint in the prior art counts. The disclosure must be enough to amount to anticipation. Australian courts have adopted the language of the English Court of Appeal in General Tire & Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 457: if the earlier publication contains a clear description of, or clear instructions to do or make, something that would infringe the claim if carried out after grant, the claim lacks novelty. The invention must be disclosed, not merely foreshadowed. A prior document that is only a signpost on the road to the invention, one that leaves the skilled reader to work the rest out, does not anticipate.

The Federal Court put the same standard in Nicaro Holdings Pty Ltd v Martin Engineering Co (1990) 91 ALR 513: the prior art must disclose all the features of the invention in clear, unequivocal and unmistakable terms, and must enable the notional skilled addressee at once to perceive, understand and practically apply the discovery without further experimentation.

The skilled addressee and common general knowledge

Novelty is not judged from the perspective of the ordinary person. It is judged from the perspective of the person skilled in the relevant art, sometimes called the skilled addressee: the notional person to whom the specification is addressed and who would read it with the common general knowledge of the field. In Root Quality Pty Ltd v Root Control Technologies Pty Ltd [2000] FCA 980, the Federal Court described the skilled addressee as the person whose knowledge determines whether a patent is novel.

Common general knowledge (CGK) is the background knowledge and experience available to everyone in the trade: what the well-informed worker in the field would be taken to know without having to look it up. The High Court described it in Minnesota Mining and Manufacturing Co v Beiersdorf (Australia) Ltd (1980) 144 CLR 253 as the background knowledge and experience available to all in the trade when considering new products or improvements.

The skilled addressee matters in two ways. First, the prior art document is read the way such a person would read it, with their knowledge of the field. Secondly, CGK is central to the separate requirement of inventive step: under section 7(2) of the Patents Act, an invention lacks an inventive step if it would have been obvious to a person skilled in the art in the light of the common general knowledge.

How lack of novelty leads to revocation

Section 138 of the Patents Act allows the Minister or any other person to apply to a prescribed court, in practice the Federal Court, for an order revoking a patent. The court may revoke the patent wholly or so far as it relates to a particular claim, and one of the grounds is that the invention is not a patentable invention, which includes lack of novelty.

In practice, revocation for lack of novelty is usually raised as a defence or cross-claim when the patentee sues for infringement. In Meyers Taylor itself, the infringement action was met with a counterclaim for revocation based on an earlier United States patent. The same question can also be tested earlier, when the application is examined by IP Australia or opposed before grant. An applicant for revocation must satisfy the court on the balance of probabilities that the ground is made out, and the patentee is entitled to begin and give evidence in support of the patent.

A worked example: the collapsible crate

Aussie Crate Co, a Melbourne manufacturer, holds a standard patent for a collapsible shipping crate with interlocking corner posts that lock without tools. It sues a competitor, Rapid Logistics, for selling a similar crate. Rapid defends on the basis that the patent should be revoked for lack of novelty, relying on a 2009 United States patent for a collapsible pallet crate that also has interlocking corner posts.

The court applies the reverse infringement test. It construes claim 1 of Aussie Crate's patent and asks whether the 2009 patent, if it were valid, would be infringed by the claimed invention. The 2009 patent shows the corner posts and the collapse mechanism, so most integers are present. But the American specification shows the posts locked with a separate pin, while Aussie Crate's claim requires posts that lock without tools. Because the earlier document does not disclose that essential integer, the claim is not anticipated. The revocation ground fails, and the infringement case proceeds.

Suppose instead the 2009 patent had described posts that snap together by friction without tools, in terms clear enough for a skilled reader to build them at once. The reverse infringement test would then be satisfied: the earlier document discloses every essential integer of claim 1, so the claim lacks novelty and is revoked. The fact that the American crate was never sold in Australia would not save it. An anticipation that exists only on paper can still destroy novelty if it was publicly available before the priority date.

Common misconceptions about patent novelty

Four misconceptions recur in novelty disputes:

• You can mosaic several documents together: The most common error is taking a feature from one old patent and a feature from another, then arguing the combination anticipates the invention. That is not permissible. Aickin J in Minnesota Mining and Manufacturing Co v Beiersdorf (Australia) Ltd described the prohibited mosaic as picking out individual items of information from prior publications and assembling them so that they appear to be a unity, and then alleging that the mosaic reveals the invention. The statutory exception in section 7(1)(b) of the Patents Act only permits combining related documents where a skilled person would treat them as a single source, such as where one document incorporates another by reference.
• "It was obvious, so it lacks novelty": Novelty and inventive step are different requirements, tested differently. Obviousness is about whether the invention would have been obvious to the skilled person in light of the common general knowledge under section 7(2). Novelty is about whether the invention was already disclosed. An invention can be novel yet obvious, or non-obvious yet anticipated.
• Common general knowledge on its own defeats novelty: CGK feeds into inventive step, not novelty. For novelty there must be prior art information made publicly available. General industry knowledge that no one published cannot anticipate a claim.
• The prior art must match the product exactly: The comparison is with the invention as claimed, not with the commercial product, and the prior disclosure is read as a skilled person would read it. It does not need to describe the invention in identical words.

When you need a patent lawyer

Novelty is a technical, evidence-heavy question, and the cost of getting it wrong is high. A patent lawyer or patent attorney can search the prior art properly, construe the claims, and give an opinion on whether a particular document is novelty-destroying before you commit to expensive litigation. If you are the patentee, that opinion tells you whether your patent is worth enforcing. If you are accused of infringement, it tells you whether revocation is a realistic defence.

In litigation, the lawyer's work is largely about evidence. They will identify the relevant prior art, brief expert witnesses who can give evidence about what a skilled addressee would understand, and argue claim construction before the court. They can also advise on whether the specification can be amended to remove a ground of revocation, which may save a patent that would otherwise be lost, but only where the amendment is allowable under the Patents Act.

Check your claims against a single earlier disclosure

The question that decides most novelty disputes is simple to state and hard to answer: is there one document or act, publicly available before the priority date of your claim, that discloses every essential integer of that claim in clear and unmistakable terms? Before you sue for infringement, or before you concede a revocation attack, ask that question about each claim you rely on. If the answer is yes, the claim is at risk. If you cannot answer it with confidence, a validity opinion from a patent lawyer is the cheapest insurance you will buy in the dispute.