PCT – the Patent Co-operation Treaty

Patent protection can be obtained for inventions in over 150 countries via the Patent Co-operation Treaty (PCT).

A PCT application does not result in the grant of a ‘world patent’. Instead, PCT applications extend the deadline for lodging a  patent application in PCT member jurisdictions until  30 or 31 months from the first filed application for the invention.

Advantages of a PCT application

A comprehensive international patent search is conducted and a written opinion on patentability given. This means that the application is examined before the bulk of the costs associated with filing patent applications overseas are incurred. The written opinion is a good, but not perfect, guide to the prospects of securing patent protection in individual countries.


The cost of filing patent applications overseas can be deferred between 30-31 months from the first filed patent application, while maintaining options to obtain patents in many countries.


All countries to which the Patent Co-operation Treaty applies are nominated in the initial application. However, the final decision on where to patent an invention can be deferred until close to the 30 or 31 month deadline for filing in individual countries.

This gives further time to explore the commercial potential of the invention and identify the countries in which protecting the invention is a priority.


A PCT application accompanied by a complete patent specification must be filed at the before the invention has been disclosed publicly anywhere in the world, or (more commonly) within 12 months of first filing an application in respect of the invention. World Intellectual Property Organisation (WIPO) in Geneva administers the PCT.


A comprehensive international search will be conducted within 2-4 months of filing the PCT application. The international search will identify relevant written disclosures (“prior art”) concerning the general subject matter of the invention.

The international search and accompanying written opinion provides a useful indication of the extent to which the invention is novel (and therefore patentable) and whether it would be advisable to adjust the scope of the claims.

Within two months of receiving the search report you may amend the patent claims if necessary, to distinguish the invention from any prior art disclosed by the patent search. No arguments can be made at this time. Accordingly, this procedure is suited to cases where there is a clear amendment that can be made to overcome the prior art and supplementary arguments are not required.

Alternatively, if the search indicates the invention is not particularly novel, then you may decide to abandon the application before committing to the expense of filing patent applications overseas.


Within 22 months of the first filed application (or within 3 months of the date of the search report and written opinion), you have the option of filing a demand requesting examination of the PCT application.

Requesting International Preliminary Examination provides an opportunity to respond to the written opinion by argument in addition to, or instead of, by making amendments. If time permits, the examiner will issue a further written opinion with further objections to which a further response can be filed. In this respect, an International Preliminary Report of Patentability (IPRP) must be established by 28 months from the first filing. The IPRP will either state what objections are outstanding or indicate that in the international examiner believes that the claims are patentable.

When the IPRP is received you will have a strong indication as to the strength of any patent that might be obtained when patent applications are filed in the countries of interest at the end of the PCT process.

This stage is called International Preliminary Examination, because no decision is made by an examiner as to whether or not a patent should be granted. That is left to the examining authority of each country in which you seek protection during the National Phase.


In the National Phase patent applications must be filed in each of the countries where you still want to obtain patent protection. It is at this time that the costs of filing a patent application in each country of interest are incurred. As indicated above, the deadline for filing national phase applications is 30 or 31 months from the first filed application depending on the country.

Once national phase has been entered the application is subject to the examination processes of each country

Alternative or additional to the PCT – Convention applications

If you are only interested in obtaining patent protection in a small number of countries, an alternative to filing a PCT application is to file a convention patent application directly into the country or countries of interest within 12 months of the first filed application.  Such convention applications are also needed for countries that are not members of the PCT.

In most countries, if an overseas application is filed within 12 months of the filing date of first patent application, the Paris Convention states the member countries to the convention will recognize filing date as a the date at which of the invention should be assessed.



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