What are an international patent application (PCT) and an international search report (ISR)?

Stacked paperwork

Legal background – the role of the PCT application

Most inventors and companies (called “applicants” in the patent world) start the process of obtaining patents by filing a patent application in a single jurisdiction, typically where the invention is likely to be sold first. However, many applicants for patents have the ambition of later expanding their sales internationally and this requires a global patent coverage.

For a patent to be granted in any country, it should relate to an invention that is new and inventive. Since applicants publish their own inventions (and if they don’t, the patent offices do), these inventions, strictly speaking, are no longer new and inventive when they wish to sell the product in other countries.

In realizing this issue, countries came together to enact two international agreements – the Paris convention and the Patent Cooperation Treaty (PCT). The purpose of these agreement is to give applicants some time to submit applications in other countries, even after the inventions have been published. The way this is done is by allowing applicants who submit an application to claim priority to an earlier patent application that was submitted for the same invention. When a priority is legally claimed, the later application is considered as if it was submitted together with the earlier application. The ability to claim priority is what makes it possible for applicants to expend their patent protection globally.

The Paris Convention awards applicant the possibility of claiming priority to an application filed up to 12 months ago. The use of the Paris convention is free and any applicant enjoys this right automatically. Almost all the countries in the world are members of the Paris convention and even the ones that are not will normally award the same rights.

However, very few applicants are ready for an international expansion 12 months after their initial application date.

The Patent Cooperation Treaty (PCT) awards more time (typically an additional 18-19 months) for claiming priority. However, to enjoy these rights an applicant must submit (or “file”) an international patent application under the PCT treaty (“PCT application”). This application carries a fee and is normally done by patent attorney firms.

It is important to understand that despite its extremely confusing name, an international application does NOT grant any patent rights. It really is, and should be called, an extension application. The main function of the PCT application is to allow applicants more time to claim priority to its original application. The applicant still has to submit independent applications in each country where patent protection is desired. The main function of the PCT is to give the applicant more time to do so.


PCT applications are called “international patent applications for historical reason. The founders of the PCT were hoping that one day, it will be possible to submit a single international application that will grant worldwide cover, but this never happened (and is unlikely to happen in the future).


The international search report (ISR)

To determine whether a patent meets this criteria, patent examiners in each country conduct a search to identify “prior art” – that is – publications that have already been known when the patent applications was published. The determination of whether a patent application is new and inventive is made by comparing it to the prior art.

Apart from the PCT’s most important role – to allow applicants more time to submit national application and claim priority to an earlier application – the PCT also includes a mandatory patent search. This search is called ISR.

Since PCT applications do not grant patent rights, this search does not lead directly to any patents being granted or refused. It is, however, very important because each and every one of the national examiners in the different countries where the patent will eventually be filed will have access to it. Many of the national patent examiners will use the PCT search as a starting point to their own reports. It is therefore important to review what has been found in this search.

How to read the ISR?

Any publications mentioned in the PCT search report are marked by letters.

X means that the publication is considered to be similar to the claims listed on the right column.

Y means that two or more publications were combined to reach the conclusion that the inventiveness of the claims listed on the right column is not sufficient.

A refers to a publication that serves as background information and is not relevant to your invention. In other words, you can usually ignore A publications.


The written opinion

For most PCT applications, the search is followed by a written opinion of the examiner. This written opinion explains how the search results apply to the invention. It also indicates whether the examiner believes that any of the claims in your invention are new and inventive.

Originally posted 2017-09-25 16:07:43.

Zeev Fisher


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