• Filing an application for a European patent for an invention

The application for European patent consists of a request for issuing a European patent; the description of the invention disclosing in detail its technical essence and advantages so that it can be realized by those skilled in the art; at least one or more patent claims defining the scope of the legal protection; technical drawings, if necessary, and an abstract. State fees are due at the initial stage of filing a patent application. Besides, additional fees may also be charged when the patent claims are over 15 in number, as well as for each additional page over 35th in the description.

  • Search and issuance of report. Preliminary opinion on the registerability (patentability) of the invention

The European Search Report is important for the patent procedure. It lists all background documents available to the European Patent Office (EPO) that are relevant to the global assessment of the the main criteria for patentability of the invention: novelty and inventive step, as well as its industrial applicability. The European search report, based on the formulated claims, takes also into account the description and the drawings. In addition to the report, the European Patent Office issues the initial, non-binding opinion on the registerability (patentability) of the invention. It indicates whether the invention filed for a patent (the filed application for a European patent) meets all the requirements of the European Patent Convention. Both documents are sent together to the applicant (or his European patent attorney) to assess the results and decide whether and how to proceed with the procedure for the issuance of a European patent.

  •  Publication of the application for a European patent

The publication of the application for a European patent is made in the Bulletin of the European Patent Office 18 months after its filing. It must contain: the description, the patent claims, all drawings, the abstract and the European search report, provided that it is drawn up in time, but if it is not ready at that time, it is published independently at a later stage.An earlier, accelerated publication is possible at the declared request of the applicant. From the date of the publication of the application for a European patent, a temporary protection of the invention is conferred in the countries designated in it, provided that it meets the requirements of the national (local) legislation, which sets a number of requirements including a translation into the official language of each state and publication of these patent claims. As it is known the claims determine the scope of the sought protection.

  • Filing the request for patent examination, payment of the due fees for the designated countries and the annual patent fees, as well as a response to the preliminary opinion

Within 6 months from the date of publication of the European Search Report, if the applicant wishes to continue with the procedure for granting a European patent, it is necessary a request for an expertise to be submitted, as well as the necessary fees for its implementation to be paid. The fee is formed according to the number of the designated countries. In addition, the applicant is obliged to pay the patent fees for the third and each subsequent patent year in a timely manner. At the presence of remarks in the preliminary opinion on patentability (registerability of the invention) it is necessary in the specified 6 months deadline, to be send a well-grounded response (preferably by a qualified patent attorney) and/or to be made the mandatory correction of the patent claims.

  • Expertise on the merits

The examination in substance of each application for European patent usually starts between 24 and 48 months from the filing of the application. It mainly involves communication with experts from the European Patent Office (EPO), which is in written or verbal form. This is necessary in order the applicant to be given the opportunity to overcome the objections of the expertise and to satisfy the mandatory requirements for registerability (patentability) of the invention, which are: novelty, inventive step and industrial applicability. The applicant, through the authorized patent representative, files his arguments and/or makes the required changes in the description and/or the patent claims of the filed application for a European patent.

  • Issuance of a European patent for invention

Once the examination in substance of the European patent has been completed and a consent with the expertise is reached concerning the patentability (registerability) criteria of the said invention, the European patent application is deemed to have been approved. For the issuance of a European patent, the patent claims have to be translated into the other two official languages of the European Patent Office, as well as to be paid the required fees for: issuing a protection document (certificate) and publication of the registered invention. This is done within 4 months from the notification of the European Patent Office. The due fees are formed on the basis of the number of the patent claims, and for each page of the description over 35 an additional fee is charged. The term for filing an opposition to the issued European patent, which is 9 months, starts from the date of the issuance of the patent. During this period, any third party may lodge an opposition (motivated and justified) against the registrability (patentability) of the issued European patent. Up to that stage, it is necessary the annual fees for maintaining the European patent to be paid to the European Patent Office. The maintenance patent fees in the following years for the term of the European patent shall be paid to the local patent offices (industrial property offices) of the designated countries.

  • Validation of a European patent

In order the issued European patent for an invention to acquire effect on the territory of each country elected by the applicant, it is necessary he (or his authorized patent representative) within 3 months of the publication of the registration, to file a certified translation of the patent claims and/or of the entire patent description, in the relevant language of the said State, and as well to pay the relevant fees for the publication of the registered patent. In some countries it is possible this period to be up to 6 months after the publication of the registration of the European patent. It should be noted that the compliance with these deadlines is of great importance, as non-compliance with these requirements will normally lead to the non-entry into force of the European patent for that country, from the very beginning of the filing an applicator with the European Patent Office (EPO).

  • Annual patent fees

After the registration of the invention, the applicant is obliged to pay the annual patent fees for the maintenance of the European patent for invention. These fees need to be paid on time annually, to the local industrial property offices (national patent offices), in the countries where the European patent is validated (already valid). These fees are usually updated for each subsequent calendar year.

  • Expiration of the term of protection of the patent

The maximum term of protection of the issued European patent for invention is 20 years, starting from the priority date of filing the application. For this purpose, it is necessary the maintenance fees to be paid regularly on time every year. Not complying with this requirement, the European patent will be terminated earlier than expected due to the applicant's failure to pay the due renewal fees. It should be noted that after expiration of the maximum possible period of validity of the registration, which is 20 years, the subject of the European patent for invention becomes available and free for use by any third party.


All stated deadlines are approximate and run from the priority date of filing the application for patent for an invention.

Patent Bureau Plovdiv