“It always seems impossible until it is done”


A patent is a powerful business tool for companies to gain exclusivity over a new product or process, develop a strong market position and earn additional revenues through licensing.

What is a patent?

A patent is an exclusive right granted by the State for an invention that is new, involves an inventive step and is capable of industrial application. In general, an invention is defined as a new and inventive solution to a technical problem in all fields of technology. Inventions may also be protected by utility model registration, if the country concerned provides such type of protection for inventions.


Apart from the technological aspects of an invention, other types of protection in terms of the brand and/or aesthetic features of a product may be acquired through trademark registration and/or industrial design registration respectively.

How is an invention judged to be new or novel?

An invention is new or novel if it does not form part of the prior art. In general, prior art refers to all the relevant technical knowledge available to the public anywhere in the world prior to the first filing date of the relevant patent application. It includes, granted patents, patent applications, non-patent literature of all types and use of invention. Over 80 % of the world’s technical knowledge can now be found in patent documents.

When is an invention considered to “involve an inventive step”?

An invention is considered to involve an inventive step (or to be non-obvious) when, taking into account the prior art, the invention would not have been obvious to a person skilled in the particular field of technology. The non-obviousness requirement is meant to ensure that patents are only granted in respect of truly creative and inventive achievements, and not to developments that a person with ordinary skill in the field could easily deduce from what already exists.

What is meant by “capable of industrial application”?

To be patentable, an invention must be capable of being used for an industrial purpose. An invention cannot be a mere theoretical phenomenon; it must be useful and provide some practical benefit. The term “industrial” is meant here in the broadest sense as anything distinct from purely intellectual or aesthetic activity, and includes, for example, agriculture.

What rights are granted by patents?

A patent grants its owner the right to exclude others from commercially using the invention for a limited period of time, usually 20 years as from the filing date. This includes the right to prevent or stop others from making, using, offering for sale, selling or importing a product or process, based on the patented invention, without the owner’s permission. It is important to note that a patent does not grant its owner the “freedom to use” or the right to exploit the technology covered by the patent, but only the right to exclude others. In fact, patents owned by others may overlap, encompass or complement your own patent. You may, therefore, need to obtain a license to use other people’s inventions in order to commercialize your own patented invention and vice versa. The use and exploitation of technology remain subject to national laws and regulations.


The legal scope of protection shall be determined by the patent claims in the granted patent.

How long does patent protection last?

The current international standard provides for a term of protection of 20 years from the filing date of the application, provided the patent renewal fees or patent maintenance fees are paid on time and no request for invalidation or revocation has been successful during this period.


In some countries, protection may be extended beyond 20 years or a Supplementary Protection Certificate (SPCs) may be granted in very specific circumstances. This is the case, for example, for patents on pharmaceuticals, due to delayed commercialization resulting from time required to obtain marketing approval from the appropriate governmental authorities. SPCs have a limited duration and generally cannot exceed five years.

Where do patents provide exclusive rights?

Patents are territorial rights, which means that an invention is only protected in the countries or regions where patent protection has been obtained. In other words, if you have not been granted a patent with effect in a given country, your invention will not be protected in that country, enabling anybody else to make, use, import or sell your invention in that country.

How do you apply for patent protection abroad or in many territories?

There are three main ways of protecting inventions abroad:


  • The national route – by filing a national patent application with the national patent office of each country of interest, in the prescribed language and paying the required fees under the national law. For instance, for the territory of Bulgaria, applicants should file a Bulgarian Patent Application with the Bulgarian Patent Office (BPO). This path may be very cumbersome and expensive if the number of countries is large.


  • The regional route – when a number of countries are members of a regional patent system, i.e. the member states of the European Patent Convention (EPC), you may apply for protection, with effect in the territories of all or some of these, by filing a single application at the relevant regional office, i.e. by filing a European Patent Application with the European Patent Office (EPO).


  • The international route – provides an opportunity for protecting an invention in any of member states/countries of the Patent Cooperation Treaty (PCT), by filing a single international PCT application. To be eligible to do so, the applicant must be a national or resident of a PCT Contracting State or have a real and effective industrial or commercial presence in one of these countries. This application may be filed either at national or regional patent offices, called Receiving Offices or directly at the World Intellectual Property Office (WIPO) as a Receiving Office in Geneva, Switzerland.



Bulgarian patent shall be granted for inventions in any field of technology, which are new, involve an inventive step and are susceptible of industrial application.

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The basic task of the European Patent Convention (EPC) is to grant patent protection using a single European procedure for the grant of patents on the basis of a single European patent application

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PCT application makes it possible for patent applicants or inventors to file single centralised international application in one patent office (receiving office)

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The basic principle of the patent system is that in return for the exclusive right provided by a patent, the patent applicant or patentee is required to disclose the invention to the public by providing a detailed..


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As a Bulgarian patent attorney with experience in various technological fields, I assist my clients in identifying patentable inventions in all fields of technology and prosecuting them further before the Bulgarian Patent Office..


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As an EQE qualified European Patent Attorney, M.Sc. Konstantin Tahtadjiev has been providing high-quality counseling and representation in patent cases before the European Patent Office (EPO)..


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A granted European Patent does not automatically provide exclusive rights to its proprietor in all of the designated contracting states in the European Patent application…


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Our dedicated team of patent attorneys is ready to assist you by providing a reliable, high-quality and cost-effective European Patent validation and translation service in Bulgaria…


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Filing and prosecuting a PCT application is rather complex and cumbersome process. However, filing a PCT application is very strategic approach for many companies…


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Entering PCT national phase before EPO, the so called EURO-PCT Phase, must take place within 31 months following the priority date of the PCT application. In practice, the EURO-PCT phase is a mixture between PCT and …


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Entering PCT national phase in Bulgaria must take place within 31 months following the priority date of the PCT application. At this point, the PCT application transforms into an independent Bulgarian patent…


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Maintaining your granted patents alive by paying their respective patent renewal fees is a crucial task for your business. Huge patent portfolios experience significant difficulties in monitoring…


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Supplementary protection certificates (SPC) for products and devices enjoying patent protection in Bulgaria shall be granted under the terms and procedure provided…


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In opposition, appeal and revocation proceedings the legal competence coupled with the technical patent qualification counts above all else…


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In the knowledge economy of today, the patent strategy of an innovative enterprise should be a key factor in its business strategy, coupled with the prior art and FTO searches….


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  • Strong market position and competitive advantage
  • A powerful tool to take action against imitators and free riders
  • Easier to enforce
  • Exclusivity over innovative inventions for 20 years
  • Higher profit or returns on investment
  • Additional income from licensing or assigning the patent
  • Access to other technologies through cross-licensing
  • Access to new markets
  • Diminished risks of infringement
  • Enhanced ability to obtain grants and/or raise funds at a reasonable rate of interest
  • Positive image for your enterprise

European Patent Validation Procedure -


Bulgarian and EQE qualified European Patent Attorney with technical and scientific background

We have been in the patent domain for over 35 years and gained considerable experience over time

Our clients say that we are objective, accurate, punctual, exhaustive and reliable

We put great importance on the relationship between costs and benefits for our clients

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