Types of applications
Patent applications are filed at national patent offices and once granted they protect the invention in the country where it was filed. There are two exceptions however:
A PCT application is filed at a PCT Receiving Office (RO). The PCT procedure makes the filing of a patent application in several country easier as it is initially done in one office in one language. This procedure does not result in an international patent (there is no such thing as an international patent) but the initial search is performed by an International Searching Authority (ISA), which then issues a written opinion on the patentability of the invention. The applicant can then choose to demand a preliminary examination, which is conducted by an International Preliminary Examining Authority (IPEA). The application is then finally referred to the national authorities in the countries where the applicant wishes to apply for a patent and a patent is issues by the national patent authority given that the application is applicable to national law.
An EPC application is filed at the European Patent Office or at a national office in an EPC contracting state. The applications are examined and granted by the EPO but the applicant can choose to validate the granted patent in any of the contracting states.
Country codes on patent documents