The first step in building up patent protection is the filing of a first patent application, a so-called ‘premier depot’ (first filing), obviously before the invention is or will be disclosed. The filing date of the first filing is called the ‘priority date’, and this date will be decisive for the assessment of the novelty of the invention in all countries where a patent application is filed. If desired, the invention may thus be disclosed after this first filing.

The premier depot offers a priority right for each country which is a member of the Union Treaty (almost all countries), which can be used within one year after the priority date (priority year).

When filing a subsequent patent application, in which a patent is applied for, for the same subject, or for a part of that subject, the priority right may be invoked. The priority date then applies to the extent that the invention has been described in the first filing. The subsequent application may be a European patent application, a PCT patent application or even a patent application in the same country as the country where the first filing was filed.

By using the priority system, it is not necessary to immediately apply for patents in all possible countries at an early stage. By filing the premier depot, the possibility to patent the invention ‘worldwide’ is secured for one year. During that priority year, it can be examined:

1. what the economic value of the invention is,
2. in which countries it makes sense to apply for a patent, and
3. to what extent the invention is considered to be novel.