In order to obtain a granted patent, it is necessary to file a patent application with the relevant Patent Office (e.g. the UK Intellectual Property Office for UK patents, the European Patent Office for European patents, the US Patent and Trademark Office for US patents).
A patent application specifies the applicant(s) for a patent and includes a patent specification which describes the invention and includes claims which set out the scope of protection which the applicant(s) seek.
Most Patent Offices publish patent applications, typically about 18 months after the priority date, and republish the patent specification if and when a patent is granted. This means that if you are viewing a published patent specification it is important to be clear whether you are reading a patent application as first published, or a patent as granted (or even as amended post-grant).
The patent applications procedure varies between territories. In the UK and Europe, and many other territories, patent applications are examined in depth to determine whether they meet the requirements for patentability. However there are countries where patents are examined in less depth or granted after only a formality examination.
An important feature of the patent application procedure is that by international convention, it is possible to file a patent application first in a single territory (e.g. the UK, Europe, the US etc.) and then to file further applications in other territories within one year of the filing date of the first application for the same invention which “claim priority” from the first application. If a later application validly claims priority from the first application then it will be judged for novelty and inventive step as of the filing date of the first application, for subject matter which the applications have in common. This means that it is usually possible to defer the choice of where to seek protection – and the costs of filing patent applications internationally – for a year from the filing of a first application.