The confusion and misunderstanding about “international patents” arises sometimes from the PCT process of pursuing patents. When looking at a PCT application, many people erroneously, but understandably, conclude that it is an application for a patent that will be valid in multiple countries. Indeed on the front page of older PCT applications, there is a heading titled “Designated states” followed by a list of two letter codes. Each of those codes stands for a country (e.g., AU, Australia; CA, Canada; CN, China, and so on) in which the applicant might have considered filing a patent application. There can be as many as about 110 countries listed. However, this list does not mean that the application is a patent, or even will become a patent, in all of these countries.
Through an international treaty (Paris Convention Treaty), a group of countries agreed to not discriminate against each other by affording patent applicants in these countries a one-year period in which to file an application in one of the other countries without losing the benefit of their filing date. The advantage is that any “art” that became known after the original filing date in the home country but before the filing date in another country could not be cited against the application. Thus, for example, if you originally file an application for your invention in Canada, you could wait up to one year before filing the application in Mexico. This would give you time to see if the costs of filing in other countries is justified.
Later, a second treaty (Patent Cooperation Treaty (PCT)) established another route to delay the additional filings in other countries. In this method, an international office was set up (World Intellectual Property Office (WIPO)) to receive and process the applications. But now, the applicant has one year to file at the WIPO office and by designating member countries she preserves her rights and original filing date in those designated countries without having to go to the expense of actually filing in each country. This saves an enormous amount of money! Eventually to obtain a patent in these countries, the application does need to be filed in the national patent offices (the process is called “conversion”), pay fees, have translations done and comply with the regulations of each individual office. Depending on some procedural issues and fee payments, the applicant has 18-30 months from the original filing date (the date the application was filed in the home country) to file in each of these other countries. Given the costs, most applications are not filed in every country designated, and many are filed in only a few countries.