Crash course on patents: Requirements for patentability

If an invention is considered to be in a permissible field of endeavor, it still must pass a substantive examination before a patent can be granted for it. There are three important requirements that an invention must satisfy: the invention must be novel, the invention must be inventive, and the invention must have industrial applications. When assessing the novelty and inventiveness of an invention, only documents published before the day of filing (or day of filing of the priority application, if there is one) are to be taken into account. These documents are often referred to as "the state of the art" or "the prior art".


The first requirement for any invention is that it is novel in the absolute sense. That is, it was not available to the public in any way before the filing date of the patent, and was not described in any publication before that date either (see When is something prior art against a patent?). Some countries, most notably the USA, have a so-called "grace period". Publications by the inventor during the grace period, which can range to up to one year before the filing of the patent application, are not regarded when determining the novelty of the invention.

The novelty requirement is fairly strict: the complete invention must be described in one single document for that document to be considered novelty-destroying. To take the canonical example, if the invention describes that something is connected to a wall with a nail, and the publication describes the very same system except with the use of a screw instead of a nail, then the invention is novel with respect to that publication.

In some cases, the determination of novelty can get extremely picky. For example, if a publication describes a chemical process involving the use of between 5 and 15% of a specific substance, and the invention lies in the use of exactly 10% of that substance, then the invention is novel because the value of 10% was not mentioned in the publication. On the other hand, if the invention lies in the use of exactly 15% of that substance, then the invention is not novel.

Of course, a skilled person will generally understand that a nail can easily be replaced by a screw or that he could choose, for example, a value of 10% in the method. However, in patent law, is it considered to be a matter of obviousness, and not of novelty. In some cases, this distinction can be very important.


Even if an invention is found to be novel in the strict sense, it may still be unpatentable because it is considered to be obvious to a person skilled in the art. It should be stressed that the term obvious is a legal term of art, and is used in a sense quite different from the ordinary meaning of the word. Further, the legal interpretation of the term obviousness varies from country to country.

In general, it can be said that something is obvious if it can be demonstrated that the literature at the time of the invention contains a suggestion or a hint to apply that measure in a situation in which it was applied in the invention. It is not permitted to use hindsight when assessing obviousness. The invention could lie in the insight that several measures are to be combined, and in hindsight the combination could then appear obvious. But it was only obvious after the inventor made the combination!

So, for example, something is obvious when it is mentioned in a standard text book, or when a document explicitly refers to another document, which other document completely describes the additional measure. It is, however, in general not obvious merely when was in fact described in a publication. It must be demonstrated that the skilled person would be led to that publication and would apply it in a situation as it occurred in the patent.

The European Patent Office has a slightly more strict interpretation of this requirement, and uses the term "inventive step" to stress this. An invention involves an inventive step if it provides a solution to a technical problem which can be found in the state of the art, and this solution is not obvious for a person skilled in the art. If no technical problem can be found, there is no inventive step. How this works in practice is discussed in more detail in When is an invention obvious?.

The requirement for an inventive step is also present in the Patent Cooperation Treaty (PCT) but a footnote remarks that the term "inventive step" may be read as "not being obvious".

Industrial application

The third requirement for patent protection mainly aims to distinguish between aesthetical and scientific inventions. The term "industry" should be interpreted very broadly; it also includes agriculture. It does exclude methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practice on the human or animal body. Perpetual motion machines also fail to meet this requirement.

In the US, the third requirement is referred to as "utility"; however, interpretation and scope of this term is generally the same as that of the industrial application. International patent treaties often use "utility" and "industrial application" as synonyms.

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